{"id":9101,"date":"2025-07-17T14:52:14","date_gmt":"2025-07-17T14:52:14","guid":{"rendered":"https:\/\/www.vipservis.com\/blog\/?p=9101"},"modified":"2025-07-17T14:52:30","modified_gmt":"2025-07-17T14:52:30","slug":"ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi","status":"publish","type":"post","link":"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/","title":{"rendered":"SSH Ba\u011flant\u0131 Problemleri Nas\u0131l \u00c7\u00f6z\u00fcl\u00fcr? Kesin \u00c7\u00f6z\u00fcm Rehberi"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_79_2 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">\u0130\u00e7indekiler<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #ff0f0f;color:#ff0f0f\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #ff0f0f;color:#ff0f0f\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#SSH_Baglanti_Problemleri_Nasil_Cozulur_Kesin_Cozum_Rehberi\" >SSH Ba\u011flant\u0131 Problemleri Nas\u0131l \u00c7\u00f6z\u00fcl\u00fcr? Kesin \u00c7\u00f6z\u00fcm Rehberi<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#1_Giris_SSH_Baglanti_Problemlerine_Genel_Bakis_ve_Onemi\" >1. Giri\u015f: SSH Ba\u011flant\u0131 Problemlerine Genel Bak\u0131\u015f ve \u00d6nemi<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#SSH_Nedir_ve_Neden_Kullanilir\" >SSH Nedir ve Neden Kullan\u0131l\u0131r?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#Sik_Karsilasilan_SSH_Baglanti_Problemleri_ve_Belirtileri\" >S\u0131k Kar\u015f\u0131la\u015f\u0131lan SSH Ba\u011flant\u0131 Problemleri ve Belirtileri<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#2_Temel_Kontroller_ve_Ilk_Adimlar_Sorun_Gidermeye_Baslangic\" >2. Temel Kontroller ve \u0130lk Ad\u0131mlar: Sorun Gidermeye Ba\u015flang\u0131\u00e7<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#3_Kimlik_Dogrulama_Authentication_Problemleri_ve_Cozumleri\" >3. Kimlik Do\u011frulama (Authentication) Problemleri ve \u00c7\u00f6z\u00fcmleri<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#4_Guvenlik_Duvari_Firewall_ve_Ag_Yapilandirmasi_Sorunlari\" >4. G\u00fcvenlik Duvar\u0131 (Firewall) ve A\u011f Yap\u0131land\u0131rmas\u0131 Sorunlar\u0131<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#5_SSH_Sunucu_Yapilandirmasi_Configuration_Sorunlari\" >5. SSH Sunucu Yap\u0131land\u0131rmas\u0131 (Configuration) Sorunlar\u0131<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#6_Ileri_Duzey_Sorun_Giderme_Teknikleri\" >6. \u0130leri D\u00fczey Sorun Giderme Teknikleri<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#7_Ek_Kaynaklar_ve_Yardim_Alma\" >7. Ek Kaynaklar ve Yard\u0131m Alma<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/www.vipservis.com\/blog\/ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi\/#8_Sonuc_SSH_Baglanti_Problemlerini_Onleme_ve_Surekli_Izleme\" >8. Sonu\u00e7: SSH Ba\u011flant\u0131 Problemlerini \u00d6nleme ve S\u00fcrekli \u0130zleme<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1 id=\"ssh-ba-lant-problemleri-nas-l-z-l-r-kesin-z-m-rehberi\"><span class=\"ez-toc-section\" id=\"SSH_Baglanti_Problemleri_Nasil_Cozulur_Kesin_Cozum_Rehberi\"><\/span>SSH Ba\u011flant\u0131 Problemleri Nas\u0131l \u00c7\u00f6z\u00fcl\u00fcr? Kesin \u00c7\u00f6z\u00fcm Rehberi<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<h2 id=\"1-giri-ssh-ba-lant-problemlerine-genel-bak-ve-nemi\"><span class=\"ez-toc-section\" id=\"1_Giris_SSH_Baglanti_Problemlerine_Genel_Bakis_ve_Onemi\"><\/span>1. Giri\u015f: SSH Ba\u011flant\u0131 Problemlerine Genel Bak\u0131\u015f ve \u00d6nemi<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3 id=\"ssh-nedir-ve-neden-kullan-l-r-\"><span class=\"ez-toc-section\" id=\"SSH_Nedir_ve_Neden_Kullanilir\"><\/span>SSH Nedir ve Neden Kullan\u0131l\u0131r?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>G\u00fcvenli Kabuk (Secure Shell), yayg\u0131n olarak SSH olarak bilinen, iki a\u011f cihaz\u0131 aras\u0131nda g\u00fcvenli bir kanal \u00fczerinden ileti\u015fim kurmay\u0131 sa\u011flayan bir a\u011f protokol\u00fcd\u00fcr. SSH, \u00f6zellikle uzaktan eri\u015fim, dosya transferi ve komut \u00e7al\u0131\u015ft\u0131rma gibi i\u015flemler i\u00e7in tasarlanm\u0131\u015ft\u0131r. Geleneksel ileti\u015fim protokollerinin (\u00f6rne\u011fin, Telnet, FTP) aksine, SSH t\u00fcm verileri \u015fifreleyerek yetkisiz eri\u015fimi ve dinlemeyi \u00f6nler. Bu g\u00fcvenlik \u00f6zelli\u011fi, SSH&#8217;yi \u00f6zellikle hassas verilerin ta\u015f\u0131nmas\u0131 ve uzak sistemlerin y\u00f6netimi i\u00e7in vazge\u00e7ilmez k\u0131lar.<\/p>\n<p><strong>SSH&#8217;nin Temel \u0130\u015flevleri:<\/strong><\/p>\n<ul>\n<li><strong>Uzak Eri\u015fim:<\/strong> SSH, bir kullan\u0131c\u0131n\u0131n uzak bir sunucuya veya cihaza g\u00fcvenli bir \u015fekilde ba\u011flanmas\u0131n\u0131 ve sanki yerel bir terminalde \u00e7al\u0131\u015f\u0131yormu\u015f gibi komutlar \u00e7al\u0131\u015ft\u0131rmas\u0131n\u0131 sa\u011flar. Bu, sistem y\u00f6neticilerinin ve geli\u015ftiricilerin sunuculara fiziksel olarak eri\u015fmeden bak\u0131m ve yap\u0131land\u0131rma i\u015flemlerini ger\u00e7ekle\u015ftirmelerini m\u00fcmk\u00fcn k\u0131lar.<\/li>\n<li><strong>Dosya Transferi (SFTP ve SCP):<\/strong> SSH, G\u00fcvenli Dosya Transfer Protokol\u00fc (SFTP) ve G\u00fcvenli Kopya Protokol\u00fc (SCP) gibi protokoller arac\u0131l\u0131\u011f\u0131yla dosyalar\u0131n g\u00fcvenli bir \u015fekilde bir cihazdan di\u011ferine aktar\u0131lmas\u0131n\u0131 sa\u011flar. SFTP, FTP&#8217;nin g\u00fcvenli bir alternatifi olarak, t\u00fcm verileri \u015fifreleyerek hassas dosyalar\u0131n g\u00fcvenli bir \u015fekilde ta\u015f\u0131nmas\u0131n\u0131 garanti eder. SCP ise, dosyalar\u0131 SSH \u00fczerinden kopyalamak i\u00e7in kullan\u0131lan basit bir ara\u00e7t\u0131r.<\/li>\n<li><strong>Port Y\u00f6nlendirme (Port Forwarding):<\/strong> SSH, port y\u00f6nlendirme \u00f6zelli\u011fi sayesinde, a\u011f trafi\u011fini g\u00fcvenli bir t\u00fcnel \u00fczerinden y\u00f6nlendirebilir. Bu, yerel a\u011fdaki bir hizmete, g\u00fcvenlik duvar\u0131 arkas\u0131ndan eri\u015fmeyi veya \u015fifrelenmemi\u015f bir protokol\u00fc (\u00f6rne\u011fin, HTTP) g\u00fcvenli bir \u015fekilde kullanmay\u0131 m\u00fcmk\u00fcn k\u0131lar.<\/li>\n<li><strong>Komut Y\u00fcr\u00fctme:<\/strong> SSH, uzak bir sunucuda komutlar \u00e7al\u0131\u015ft\u0131rmak i\u00e7in kullan\u0131labilir. Bu, sistem y\u00f6neticilerinin ve geli\u015ftiricilerin uzaktan toplu i\u015flemler ger\u00e7ekle\u015ftirmesini, yap\u0131land\u0131rma dosyalar\u0131n\u0131 de\u011fi\u015ftirmesini ve uygulamalar\u0131 y\u00f6netmesini sa\u011flar.<\/li>\n<\/ul>\n<p><strong>SSH&#8217;nin G\u00fcvenlik Mekanizmalar\u0131:<\/strong><\/p>\n<p>SSH, g\u00fcvenli\u011fi sa\u011flamak i\u00e7in \u00e7e\u015fitli \u015fifreleme algoritmalar\u0131 ve kimlik do\u011frulama y\u00f6ntemleri kullan\u0131r. \u0130\u015fte baz\u0131 temel g\u00fcvenlik mekanizmalar\u0131:<\/p>\n<ul>\n<li><strong>\u015eifreleme:<\/strong> SSH, verileri \u015fifrelemek i\u00e7in simetrik \u015fifreleme (\u00f6rne\u011fin, AES, ChaCha20) ve asimetrik \u015fifreleme (\u00f6rne\u011fin, RSA, ECDSA) algoritmalar\u0131n\u0131 kullan\u0131r. Simetrik \u015fifreleme, verileri \u015fifrelemek ve \u00e7\u00f6zmek i\u00e7in ayn\u0131 anahtar\u0131 kullan\u0131rken, asimetrik \u015fifreleme, bir genel anahtar ve bir \u00f6zel anahtar kullan\u0131r.<\/li>\n<li><strong>Kimlik Do\u011frulama:<\/strong> SSH, kullan\u0131c\u0131lar\u0131 ve sunucular\u0131 do\u011frulamak i\u00e7in \u00e7e\u015fitli kimlik do\u011frulama y\u00f6ntemleri sunar. En yayg\u0131n y\u00f6ntemler \u015funlard\u0131r:\n<ul>\n<li><strong>Parola Tabanl\u0131 Kimlik Do\u011frulama:<\/strong> Kullan\u0131c\u0131n\u0131n kullan\u0131c\u0131 ad\u0131 ve parolas\u0131 ile do\u011frulanmas\u0131.<\/li>\n<li><strong>Anahtar Tabanl\u0131 Kimlik Do\u011frulama:<\/strong> Kullan\u0131c\u0131n\u0131n \u00f6zel anahtar\u0131yla do\u011frulanmas\u0131. Bu y\u00f6ntem, paroladan daha g\u00fcvenlidir \u00e7\u00fcnk\u00fc parolalar\u0131n \u00e7al\u0131nmas\u0131 veya tahmin edilmesi daha kolayd\u0131r.<\/li>\n<li><strong>\u00c7ok Fakt\u00f6rl\u00fc Kimlik Do\u011frulama (MFA):<\/strong> Kullan\u0131c\u0131n\u0131n birden fazla kimlik do\u011frulama fakt\u00f6r\u00fc kullanarak do\u011frulanmas\u0131. \u00d6rne\u011fin, parola ve tek kullan\u0131ml\u0131k bir kod (OTP) kullanmak.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Anahtar De\u011fi\u015fimi (Key Exchange):<\/strong> SSH, ba\u011flant\u0131 kurulurken g\u00fcvenli bir \u015fekilde \u015fifreleme anahtarlar\u0131n\u0131 de\u011fi\u015ftirmek i\u00e7in Diffie-Hellman veya Elliptic-Curve Diffie-Hellman gibi anahtar de\u011fi\u015fim algoritmalar\u0131n\u0131 kullan\u0131r. Bu algoritmalar, man-in-the-middle (ortadaki adam) sald\u0131r\u0131lar\u0131n\u0131 \u00f6nler.<\/li>\n<li><strong>B\u00fct\u00fcnl\u00fck Kontrol\u00fc:<\/strong> SSH, verilerin b\u00fct\u00fcnl\u00fc\u011f\u00fcn\u00fc sa\u011flamak i\u00e7in MAC (Message Authentication Code) algoritmalar\u0131n\u0131 kullan\u0131r. MAC algoritmalar\u0131, g\u00f6nderilen verilerin de\u011fi\u015ftirilmedi\u011fini do\u011frular.<\/li>\n<\/ul>\n<p><strong>SSH&#8217;nin Sistem Y\u00f6neticileri ve Geli\u015ftiriciler \u0130\u00e7in \u00d6nemi:<\/strong><\/p>\n<p>SSH, sistem y\u00f6neticileri ve geli\u015ftiriciler i\u00e7in bir\u00e7ok nedenden dolay\u0131 kritik bir ara\u00e7t\u0131r:<\/p>\n<ul>\n<li><strong>G\u00fcvenli Uzaktan Eri\u015fim:<\/strong> SSH, sunuculara ve di\u011fer cihazlara g\u00fcvenli bir \u015fekilde uzaktan eri\u015fmeyi sa\u011flar. Bu, sistem y\u00f6neticilerinin sunuculara fiziksel olarak eri\u015fmeden bak\u0131m ve yap\u0131land\u0131rma i\u015flemlerini ger\u00e7ekle\u015ftirmelerini m\u00fcmk\u00fcn k\u0131lar.<\/li>\n<li><strong>Otomasyon:<\/strong> SSH, komut sat\u0131r\u0131 ara\u00e7lar\u0131 ve betikler arac\u0131l\u0131\u011f\u0131yla uzak sistemlerdeki g\u00f6revleri otomatikle\u015ftirmek i\u00e7in kullan\u0131labilir. Bu, sistem y\u00f6neticilerinin ve geli\u015ftiricilerin zaman\u0131n\u0131 ve \u00e7abas\u0131n\u0131 \u00f6nemli \u00f6l\u00e7\u00fcde azalt\u0131r.<\/li>\n<li><strong>G\u00fcvenli Dosya Transferi:<\/strong> SSH, SFTP ve SCP gibi protokoller arac\u0131l\u0131\u011f\u0131yla dosyalar\u0131n g\u00fcvenli bir \u015fekilde bir cihazdan di\u011ferine aktar\u0131lmas\u0131n\u0131 sa\u011flar. Bu, hassas verilerin g\u00fcvenli bir \u015fekilde ta\u015f\u0131nmas\u0131n\u0131 garanti eder.<\/li>\n<li><strong>G\u00fcvenlik:<\/strong> SSH, t\u00fcm verileri \u015fifreleyerek yetkisiz eri\u015fimi ve dinlemeyi \u00f6nler. Bu, \u00f6zellikle hassas verilerin ta\u015f\u0131nmas\u0131 ve uzak sistemlerin y\u00f6netimi i\u00e7in \u00f6nemlidir.<\/li>\n<li><strong>Esneklik:<\/strong> SSH, \u00e7e\u015fitli i\u015fletim sistemlerinde ve platformlarda kullan\u0131labilir. Bu, sistem y\u00f6neticilerinin ve geli\u015ftiricilerin farkl\u0131 ortamlarda \u00e7al\u0131\u015fmas\u0131n\u0131 kolayla\u015ft\u0131r\u0131r.<\/li>\n<\/ul>\n<p><strong>SSH&#8217;nin Kullan\u0131m Alanlar\u0131:<\/strong><\/p>\n<p>SSH, \u00e7e\u015fitli kullan\u0131m alanlar\u0131na sahiptir. \u0130\u015fte baz\u0131 \u00f6rnekler:<\/p>\n<ul>\n<li><strong>Sunucu Y\u00f6netimi:<\/strong> Sistem y\u00f6neticileri, SSH&#8217;yi sunuculara uzaktan eri\u015fmek, yap\u0131land\u0131rmak ve bak\u0131m yapmak i\u00e7in kullan\u0131r.<\/li>\n<li><strong>Uygulama Da\u011f\u0131t\u0131m\u0131:<\/strong> Geli\u015ftiriciler, SSH&#8217;yi uygulamalar\u0131 uzak sunuculara da\u011f\u0131tmak ve g\u00fcncellemek i\u00e7in kullan\u0131r.<\/li>\n<li><strong>Veritaban\u0131 Y\u00f6netimi:<\/strong> Veritaban\u0131 y\u00f6neticileri, SSH&#8217;yi veritabanlar\u0131na uzaktan eri\u015fmek ve y\u00f6netmek i\u00e7in kullan\u0131r.<\/li>\n<li><strong>A\u011f Y\u00f6netimi:<\/strong> A\u011f y\u00f6neticileri, SSH&#8217;yi a\u011f cihazlar\u0131na uzaktan eri\u015fmek ve yap\u0131land\u0131rmak i\u00e7in kullan\u0131r.<\/li>\n<li><strong>Bulut Bili\u015fim:<\/strong> Bulut sa\u011flay\u0131c\u0131lar\u0131, SSH&#8217;yi sanal makineleri ve di\u011fer bulut kaynaklar\u0131n\u0131 y\u00f6netmek i\u00e7in kullan\u0131r.<\/li>\n<li><strong>DevOps:<\/strong> DevOps m\u00fchendisleri, SSH&#8217;yi s\u00fcrekli entegrasyon ve s\u00fcrekli da\u011f\u0131t\u0131m (CI\/CD) s\u00fcre\u00e7lerinde otomasyon i\u00e7in kullan\u0131r.<\/li>\n<\/ul>\n<p>\u00d6rne\u011fin, bir web sunucusunu y\u00f6neten bir sistem y\u00f6neticisi, SSH kullanarak sunucuya ba\u011flanabilir, yap\u0131land\u0131rma dosyalar\u0131n\u0131 d\u00fczenleyebilir, yaz\u0131l\u0131m g\u00fcncellemelerini y\u00fckleyebilir ve sunucu performans\u0131n\u0131 izleyebilir. Bir geli\u015ftirici, SSH kullanarak yerel makinesinden bir uygulaman\u0131n yeni bir s\u00fcr\u00fcm\u00fcn\u00fc sunucuya da\u011f\u0131tabilir. Bir veritaban\u0131 y\u00f6neticisi, SSH kullanarak veritaban\u0131na ba\u011flanabilir, yedeklemeler alabilir ve sorgular \u00e7al\u0131\u015ft\u0131rabilir.<\/p>\n<p>SSH, modern bili\u015fim altyap\u0131s\u0131n\u0131n temel bir par\u00e7as\u0131d\u0131r ve g\u00fcvenli uzaktan eri\u015fim, dosya transferi ve komut \u00e7al\u0131\u015ft\u0131rma gibi \u00f6nemli i\u015flevler sunar. <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusu, bu nedenle hem sistem y\u00f6neticileri hem de geli\u015ftiriciler i\u00e7in kritik bir \u00f6neme sahiptir.<\/p>\n<h3 id=\"s-k-kar-la-lan-ssh-ba-lant-problemleri-ve-belirtileri\"><span class=\"ez-toc-section\" id=\"Sik_Karsilasilan_SSH_Baglanti_Problemleri_ve_Belirtileri\"><\/span>S\u0131k Kar\u015f\u0131la\u015f\u0131lan SSH Ba\u011flant\u0131 Problemleri ve Belirtileri<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>SSH ba\u011flant\u0131 problemleri, kullan\u0131c\u0131lar\u0131n uzak sunuculara veya cihazlara eri\u015fimini engelleyebilir ve verimlili\u011fi d\u00fc\u015f\u00fcrebilir. Bu problemlerin nedenleri \u00e7e\u015fitli olabilir, ancak genellikle a\u011f yap\u0131land\u0131rmas\u0131, g\u00fcvenlik duvar\u0131 ayarlar\u0131, kimlik do\u011frulama sorunlar\u0131 veya SSH sunucu yap\u0131land\u0131rmas\u0131yla ilgilidir. <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusunun cevab\u0131n\u0131 bulmak i\u00e7in \u00f6ncelikle bu problemleri ve belirtilerini anlamak \u00f6nemlidir.<\/p>\n<p><strong>1. Ba\u011flant\u0131 Zaman A\u015f\u0131m\u0131 (Connection Timeout) Hatalar\u0131:<\/strong><\/p>\n<p>Bu hata, SSH istemcisinin sunucuya ba\u011flanmaya \u00e7al\u0131\u015ft\u0131\u011f\u0131 ancak belirli bir s\u00fcre i\u00e7inde yan\u0131t alamad\u0131\u011f\u0131 durumlarda ortaya \u00e7\u0131kar. Belirtileri \u015funlard\u0131r:<\/p>\n<ul>\n<li>Terminalde &#8220;Connection timed out&#8221; veya &#8220;Ba\u011flant\u0131 zaman a\u015f\u0131m\u0131na u\u011frad\u0131&#8221; gibi bir hata mesaj\u0131 g\u00f6r\u00fcnt\u00fclenir.<\/li>\n<li>SSH istemcisi sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r, ancak ba\u011flant\u0131 bir t\u00fcrl\u00fc kurulamaz.<\/li>\n<\/ul>\n<p><strong>Olas\u0131 Nedenler:<\/strong><\/p>\n<ul>\n<li><strong>A\u011f Ba\u011flant\u0131s\u0131 Sorunlar\u0131:<\/strong> \u0130nternet ba\u011flant\u0131s\u0131 kesilmi\u015f olabilir veya a\u011fda bir sorun olabilir.<\/li>\n<li><strong>Sunucu Eri\u015filemezli\u011fi:<\/strong> Sunucu kapal\u0131 olabilir, bak\u0131mda olabilir veya a\u011fdan eri\u015filemeyebilir.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Engellemesi:<\/strong> G\u00fcvenlik duvar\u0131, SSH trafi\u011fini engelliyor olabilir.<\/li>\n<li><strong>Yanl\u0131\u015f Sunucu Adresi veya Port:<\/strong> Yanl\u0131\u015f bir sunucu adresi veya port numaras\u0131 kullan\u0131l\u0131yor olabilir.<\/li>\n<li><strong>MTU (Maximum Transmission Unit) Sorunlar\u0131:<\/strong> A\u011fda MTU boyutundan daha b\u00fcy\u00fck paketler g\u00f6nderilmeye \u00e7al\u0131\u015f\u0131l\u0131yor olabilir.<\/li>\n<\/ul>\n<p><strong>2. &#8220;Connection Refused&#8221; Hatalar\u0131:<\/strong><\/p>\n<p>Bu hata, SSH sunucusunun ba\u011flant\u0131 iste\u011fini reddetti\u011fi durumlarda ortaya \u00e7\u0131kar. Belirtileri \u015funlard\u0131r:<\/p>\n<ul>\n<li>Terminalde &#8220;Connection refused&#8221; veya &#8220;Ba\u011flant\u0131 reddedildi&#8221; gibi bir hata mesaj\u0131 g\u00f6r\u00fcnt\u00fclenir.<\/li>\n<li>SSH istemcisi sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r, ancak ba\u011flant\u0131 hemen reddedilir.<\/li>\n<\/ul>\n<p><strong>Olas\u0131 Nedenler:<\/strong><\/p>\n<ul>\n<li><strong>SSH Sunucusu \u00c7al\u0131\u015fm\u0131yor:<\/strong> SSH sunucusu ba\u015flat\u0131lmam\u0131\u015f veya durdurulmu\u015f olabilir.<\/li>\n<li><strong>Yanl\u0131\u015f Port Numaras\u0131:<\/strong> Yanl\u0131\u015f bir port numaras\u0131 kullan\u0131l\u0131yor olabilir. SSH sunucusu varsay\u0131lan olarak 22 numaral\u0131 portu kullan\u0131r, ancak bu de\u011fi\u015ftirilmi\u015f olabilir.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Engellemesi:<\/strong> G\u00fcvenlik duvar\u0131, SSH trafi\u011fini engelliyor olabilir.<\/li>\n<li><strong>TCP Wrappers:<\/strong> TCP Wrappers, SSH sunucusuna eri\u015fimi k\u0131s\u0131tl\u0131yor olabilir.<\/li>\n<li><strong><code>ListenAddress<\/code> Yap\u0131land\u0131rmas\u0131:<\/strong> SSH sunucusu, belirli bir IP adresine ba\u011flanmak i\u00e7in yap\u0131land\u0131r\u0131lm\u0131\u015f olabilir ve istemci farkl\u0131 bir adresten ba\u011flanmaya \u00e7al\u0131\u015f\u0131yor olabilir.<\/li>\n<\/ul>\n<p><strong>3. Kimlik Do\u011frulama (Authentication) Sorunlar\u0131 ve Hata Mesajlar\u0131:<\/strong><\/p>\n<p>Bu sorunlar, kullan\u0131c\u0131 ad\u0131n\u0131n, parolan\u0131n veya SSH anahtar\u0131n\u0131n yanl\u0131\u015f olmas\u0131 durumunda ortaya \u00e7\u0131kar. Belirtileri \u015funlard\u0131r:<\/p>\n<ul>\n<li>&#8220;Permission denied (publickey,password)&#8221; veya &#8220;Eri\u015fim engellendi (publickey,password)&#8221; gibi bir hata mesaj\u0131 g\u00f6r\u00fcnt\u00fclenir.<\/li>\n<li>&#8220;Authentication failed&#8221; veya &#8220;Kimlik do\u011frulama ba\u015far\u0131s\u0131z&#8221; gibi bir hata mesaj\u0131 g\u00f6r\u00fcnt\u00fclenir.<\/li>\n<li>&#8220;Too many authentication failures&#8221; veya &#8220;\u00c7ok fazla kimlik do\u011frulama hatas\u0131&#8221; gibi bir hata mesaj\u0131 g\u00f6r\u00fcnt\u00fclenir.<\/li>\n<\/ul>\n<p><strong>Olas\u0131 Nedenler:<\/strong><\/p>\n<ul>\n<li><strong>Yanl\u0131\u015f Kullan\u0131c\u0131 Ad\u0131 veya \u015eifre:<\/strong> Yanl\u0131\u015f bir kullan\u0131c\u0131 ad\u0131 veya \u015fifre kullan\u0131l\u0131yor olabilir.<\/li>\n<li><strong>SSH Anahtar\u0131 Sorunlar\u0131:<\/strong> \u00d6zel anahtar yanl\u0131\u015f yerde olabilir, izinleri yanl\u0131\u015f olabilir veya genel anahtar sunucuda do\u011fru konuma eklenmemi\u015f olabilir.<\/li>\n<li><strong><code>PasswordAuthentication<\/code> Devre D\u0131\u015f\u0131:<\/strong> SSH sunucusunda parola tabanl\u0131 kimlik do\u011frulama devre d\u0131\u015f\u0131 b\u0131rak\u0131lm\u0131\u015f olabilir.<\/li>\n<li><strong><code>PermitRootLogin<\/code> K\u0131s\u0131tlamalar\u0131:<\/strong> SSH sunucusunda root kullan\u0131c\u0131s\u0131n\u0131n do\u011frudan oturum a\u00e7mas\u0131 engellenmi\u015f olabilir.<\/li>\n<li><strong><code>MaxAuthTries<\/code> S\u0131n\u0131r\u0131:<\/strong> SSH sunucusunda \u00e7ok fazla kimlik do\u011frulama denemesi yap\u0131lmas\u0131 engellenmi\u015f olabilir.<\/li>\n<\/ul>\n<p><strong>4. Anahtar De\u011fi\u015fimi (Key Exchange) Hatalar\u0131 ve \u00c7\u00f6z\u00fcmleri:<\/strong><\/p>\n<p>Bu hatalar, SSH istemcisi ve sunucusu aras\u0131nda \u015fifreleme anahtarlar\u0131n\u0131n de\u011fi\u015fimi s\u0131ras\u0131nda ortaya \u00e7\u0131kar. Belirtileri \u015funlard\u0131r:<\/p>\n<ul>\n<li>&#8220;No matching key exchange method found&#8221; veya &#8220;E\u015fle\u015fen anahtar de\u011fi\u015fim y\u00f6ntemi bulunamad\u0131&#8221; gibi bir hata mesaj\u0131 g\u00f6r\u00fcnt\u00fclenir.<\/li>\n<li>&#8220;Unable to negotiate with [sunucu adresi] port [port numaras\u0131]: no matching key exchange method found. Their offer: [algoritmalar]&#8221; gibi bir hata mesaj\u0131 g\u00f6r\u00fcnt\u00fclenir.<\/li>\n<\/ul>\n<p><strong>Olas\u0131 Nedenler:<\/strong><\/p>\n<ul>\n<li><strong>Uyumsuz Algoritmalar:<\/strong> SSH istemcisi ve sunucusu, ortak bir anahtar de\u011fi\u015fim algoritmas\u0131 \u00fczerinde anla\u015fam\u0131yor olabilir.<\/li>\n<li><strong>Eski SSH S\u00fcr\u00fcmleri:<\/strong> Eski SSH s\u00fcr\u00fcmleri, daha yeni algoritmalar\u0131 desteklemiyor olabilir.<\/li>\n<li><strong>G\u00fcvenlik Politikalar\u0131:<\/strong> Sunucuda veya istemcide kat\u0131 g\u00fcvenlik politikalar\u0131 uygulan\u0131yor olabilir.<\/li>\n<\/ul>\n<p><strong>5. Ba\u011flant\u0131 Kopmalar\u0131 ve \u0130stikrars\u0131zl\u0131k Sorunlar\u0131:<\/strong><\/p>\n<p>Bu sorunlar, SSH ba\u011flant\u0131s\u0131n\u0131n aniden kesilmesi veya ba\u011flant\u0131n\u0131n s\u00fcrekli olarak kesintiye u\u011framas\u0131 durumunda ortaya \u00e7\u0131kar. Belirtileri \u015funlard\u0131r:<\/p>\n<ul>\n<li>SSH ba\u011flant\u0131s\u0131 beklenmedik bir \u015fekilde kesilir.<\/li>\n<li>Terminalde &#8220;Broken pipe&#8221; veya &#8220;K\u0131r\u0131k boru&#8221; gibi bir hata mesaj\u0131 g\u00f6r\u00fcnt\u00fclenir.<\/li>\n<li>Ba\u011flant\u0131 s\u00fcrekli olarak kesintiye u\u011frar ve yeniden ba\u011flanmak gerekir.<\/li>\n<\/ul>\n<p><strong>Olas\u0131 Nedenler:<\/strong><\/p>\n<ul>\n<li><strong>A\u011f \u0130stikrars\u0131zl\u0131\u011f\u0131:<\/strong> A\u011f ba\u011flant\u0131s\u0131nda kesintiler veya dalgalanmalar olabilir.<\/li>\n<li><strong>Bo\u015fta Kalma S\u00fcresi A\u015f\u0131m\u0131:<\/strong> SSH sunucusu, belirli bir s\u00fcre boyunca etkinlik olmazsa ba\u011flant\u0131y\u0131 kesiyor olabilir.<\/li>\n<li><strong>MTU Sorunlar\u0131:<\/strong> A\u011fda MTU boyutundan daha b\u00fcy\u00fck paketler g\u00f6nderilmeye \u00e7al\u0131\u015f\u0131l\u0131yor olabilir.<\/li>\n<li><strong>Sunucu Y\u00fck\u00fc:<\/strong> Sunucu a\u015f\u0131r\u0131 y\u00fckl\u00fc olabilir ve ba\u011flant\u0131lar\u0131 d\u00fczg\u00fcn bir \u015fekilde y\u00f6netemiyor olabilir.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 veya A\u011f Cihaz\u0131 Sorunlar\u0131:<\/strong> G\u00fcvenlik duvar\u0131 veya a\u011f cihaz\u0131, SSH ba\u011flant\u0131s\u0131n\u0131 kesiyor olabilir.<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryolar:<\/strong><\/p>\n<ul>\n<li><strong>Senaryo 1:<\/strong> Bir sistem y\u00f6neticisi, bir sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak &#8220;Connection timed out&#8221; hatas\u0131 al\u0131r. Yapt\u0131\u011f\u0131 kontrollerde internet ba\u011flant\u0131s\u0131n\u0131n oldu\u011funu ve sunucunun a\u00e7\u0131k oldu\u011funu g\u00f6r\u00fcr. Ancak, g\u00fcvenlik duvar\u0131 ayarlar\u0131nda SSH portunun (22) kapal\u0131 oldu\u011funu fark eder. G\u00fcvenlik duvar\u0131nda SSH portunu a\u00e7arak sorunu \u00e7\u00f6zer.<\/li>\n<li><strong>Senaryo 2:<\/strong> Bir geli\u015ftirici, bir sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak &#8220;Permission denied (publickey)&#8221; hatas\u0131 al\u0131r. SSH anahtar\u0131n\u0131 kontrol etti\u011finde, \u00f6zel anahtar\u0131n\u0131n do\u011fru yerde oldu\u011funu ve izinlerinin do\u011fru oldu\u011funu g\u00f6r\u00fcr. Ancak, sunucudaki <code>authorized_keys<\/code> dosyas\u0131nda genel anahtar\u0131n\u0131n eksik oldu\u011funu fark eder. Genel anahtar\u0131n\u0131 <code>authorized_keys<\/code> dosyas\u0131na ekleyerek sorunu \u00e7\u00f6zer.<\/li>\n<li><strong>Senaryo 3:<\/strong> Bir kullan\u0131c\u0131, bir sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak ba\u011flant\u0131 s\u00fcrekli olarak kesintiye u\u011frar. A\u011f ba\u011flant\u0131s\u0131n\u0131 kontrol etti\u011finde, ba\u011flant\u0131n\u0131n istikrars\u0131z oldu\u011funu fark eder. A\u011f ba\u011flant\u0131s\u0131n\u0131 d\u00fczelterek sorunu \u00e7\u00f6zer.<\/li>\n<\/ul>\n<p>Bu s\u0131k kar\u015f\u0131la\u015f\u0131lan SSH ba\u011flant\u0131 problemleri ve belirtileri, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken bir ba\u015flang\u0131\u00e7 noktas\u0131 sa\u011flar. Her bir problemin olas\u0131 nedenlerini anlamak, sorunu te\u015fhis etmeyi ve do\u011fru \u00e7\u00f6z\u00fcm\u00fc bulmay\u0131 kolayla\u015ft\u0131r\u0131r. Bir sonraki b\u00f6l\u00fcmde, temel kontroller ve ilk ad\u0131mlar ile sorun gidermeye nas\u0131l ba\u015flanaca\u011f\u0131n\u0131 ele alaca\u011f\u0131z.<\/p>\n<h2 id=\"2-temel-kontroller-ve-i-lk-ad-mlar-sorun-gidermeye-ba-lang-\"><span class=\"ez-toc-section\" id=\"2_Temel_Kontroller_ve_Ilk_Adimlar_Sorun_Gidermeye_Baslangic\"><\/span>2. Temel Kontroller ve \u0130lk Ad\u0131mlar: Sorun Gidermeye Ba\u015flang\u0131\u00e7<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>SSH ba\u011flant\u0131 problemlerini \u00e7\u00f6zmeye ba\u015flamadan \u00f6nce, sorunun kayna\u011f\u0131n\u0131 do\u011fru bir \u015fekilde belirlemek i\u00e7in baz\u0131 temel kontroller yapmak ve ilk ad\u0131mlar\u0131 atmak \u00f6nemlidir. Bu b\u00f6l\u00fcm, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap arayan kullan\u0131c\u0131lara, sorun giderme s\u00fcrecine ba\u015flamalar\u0131 i\u00e7in gerekli bilgileri ve ad\u0131mlar\u0131 sunmaktad\u0131r. Bu ad\u0131mlar, basit a\u011f ba\u011flant\u0131s\u0131 kontrollerinden, SSH sunucusunun durumunu incelemeye kadar geni\u015f bir yelpazeyi kapsamaktad\u0131r.<\/p>\n<p><strong>1. A\u011f Ba\u011flant\u0131s\u0131n\u0131 Kontrol Etmek<\/strong><\/p>\n<p>SSH ba\u011flant\u0131 problemlerinin en yayg\u0131n nedenlerinden biri, a\u011f ba\u011flant\u0131s\u0131 sorunlar\u0131d\u0131r. Sunucuya eri\u015fmeye \u00e7al\u0131\u015f\u0131rken, \u00f6ncelikle kendi a\u011f ba\u011flant\u0131n\u0131z\u0131n sa\u011fl\u0131kl\u0131 oldu\u011fundan emin olman\u0131z gerekir.<\/p>\n<ul>\n<li><strong>\u0130nternet Ba\u011flant\u0131s\u0131n\u0131n Olup Olmad\u0131\u011f\u0131n\u0131 Do\u011frulama:<\/strong>En temel ad\u0131m, internet ba\u011flant\u0131n\u0131z\u0131n aktif olup olmad\u0131\u011f\u0131n\u0131 kontrol etmektir. Bunu yapman\u0131n birka\u00e7 yolu vard\u0131r:\n<ul>\n<li><strong>Web Taray\u0131c\u0131s\u0131:<\/strong> Bir web taray\u0131c\u0131s\u0131 a\u00e7\u0131n ve bilinen bir web sitesine (\u00f6rne\u011fin, google.com, wikipedia.org) eri\u015fmeye \u00e7al\u0131\u015f\u0131n. E\u011fer web sitesi y\u00fckleniyorsa, internet ba\u011flant\u0131n\u0131z b\u00fcy\u00fck olas\u0131l\u0131kla \u00e7al\u0131\u015f\u0131yordur.<\/li>\n<li><strong>Ping Komutu:<\/strong> Komut sat\u0131r\u0131n\u0131 (Windows&#8217;ta Command Prompt, macOS ve Linux&#8217;ta Terminal) a\u00e7\u0131n ve a\u015fa\u011f\u0131daki komutu \u00e7al\u0131\u015ft\u0131r\u0131n:\n<pre><code class=\"lang-bash\"><span class=\"hljs-built_in\">ping<\/span> google.com\r\n<\/code><\/pre>\n<p>E\u011fer ping komutu ba\u015far\u0131l\u0131 bir \u015fekilde yan\u0131t veriyorsa, internet ba\u011flant\u0131n\u0131z \u00e7al\u0131\u015f\u0131yordur. Yan\u0131t alam\u0131yorsan\u0131z, internet ba\u011flant\u0131n\u0131zda bir sorun olabilir.<\/li>\n<li><strong>A\u011f Ba\u011flant\u0131s\u0131 Simgesi:<\/strong> \u0130\u015fletim sisteminizin g\u00f6rev \u00e7ubu\u011fundaki a\u011f ba\u011flant\u0131s\u0131 simgesini kontrol edin. Simge, ba\u011flant\u0131 durumunu g\u00f6sterir. E\u011fer bir hata simgesi (\u00f6rne\u011fin, k\u0131rm\u0131z\u0131 \u00e7arp\u0131) g\u00f6r\u00fcyorsan\u0131z, a\u011f ba\u011flant\u0131n\u0131zda bir sorun olabilir.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Ping Komutu ile Sunucuya Eri\u015filebilirli\u011fi Test Etme:<\/strong>\u0130nternet ba\u011flant\u0131n\u0131z\u0131n \u00e7al\u0131\u015ft\u0131\u011f\u0131ndan emin olduktan sonra, hedef sunucuya eri\u015filebilirli\u011finizi test etmeniz gerekir. Ping komutu, sunucuya bir istek g\u00f6nderir ve sunucudan yan\u0131t bekler. Bu, sunucunun \u00e7evrimi\u00e7i olup olmad\u0131\u011f\u0131n\u0131 ve a\u011f\u0131n\u0131zdan eri\u015filebilir olup olmad\u0131\u011f\u0131n\u0131 kontrol etmenize yard\u0131mc\u0131 olur.\n<p>Komut sat\u0131r\u0131n\u0131 a\u00e7\u0131n ve a\u015fa\u011f\u0131daki komutu \u00e7al\u0131\u015ft\u0131r\u0131n:<\/p>\n<pre><code class=\"lang-bash\">ping <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">sunucu_adresi<\/span>&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;sunucu_adresi&gt;<\/code> yerine, ba\u011flanmaya \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131z sunucunun IP adresini veya alan ad\u0131n\u0131 (\u00f6rne\u011fin, 192.168.1.10 veya example.com) yaz\u0131n.<\/p>\n<p><strong>Ba\u015far\u0131l\u0131 Ping Yan\u0131t\u0131:<\/strong><\/p>\n<p>E\u011fer ping komutu ba\u015far\u0131l\u0131 bir \u015fekilde yan\u0131t veriyorsa, \u015funa benzer bir \u00e7\u0131kt\u0131 g\u00f6receksiniz:<\/p>\n<pre><code>PING example.com (<span class=\"hljs-number\">93.184<\/span><span class=\"hljs-number\">.216<\/span><span class=\"hljs-number\">.34<\/span>) <span class=\"hljs-number\">56<\/span>(<span class=\"hljs-number\">84<\/span>) <span class=\"hljs-keyword\">bytes<\/span> <span class=\"hljs-keyword\">of<\/span> data.\r\n<span class=\"hljs-number\">64<\/span> <span class=\"hljs-keyword\">bytes<\/span> <span class=\"hljs-built_in\">from<\/span> <span class=\"hljs-number\">93.184<\/span><span class=\"hljs-number\">.216<\/span><span class=\"hljs-number\">.34<\/span>: icmp_seq=<span class=\"hljs-number\">1<\/span> ttl=<span class=\"hljs-number\">53<\/span> <span class=\"hljs-built_in\">time<\/span>=<span class=\"hljs-number\">7.21<\/span> ms\r\n<span class=\"hljs-number\">64<\/span> <span class=\"hljs-keyword\">bytes<\/span> <span class=\"hljs-built_in\">from<\/span> <span class=\"hljs-number\">93.184<\/span><span class=\"hljs-number\">.216<\/span><span class=\"hljs-number\">.34<\/span>: icmp_seq=<span class=\"hljs-number\">2<\/span> ttl=<span class=\"hljs-number\">53<\/span> <span class=\"hljs-built_in\">time<\/span>=<span class=\"hljs-number\">7.19<\/span> ms\r\n<span class=\"hljs-number\">64<\/span> <span class=\"hljs-keyword\">bytes<\/span> <span class=\"hljs-built_in\">from<\/span> <span class=\"hljs-number\">93.184<\/span><span class=\"hljs-number\">.216<\/span><span class=\"hljs-number\">.34<\/span>: icmp_seq=<span class=\"hljs-number\">3<\/span> ttl=<span class=\"hljs-number\">53<\/span> <span class=\"hljs-built_in\">time<\/span>=<span class=\"hljs-number\">7.20<\/span> ms\r\n<\/code><\/pre>\n<p>Bu, sunucunun \u00e7evrimi\u00e7i oldu\u011funu ve a\u011f\u0131n\u0131zdan eri\u015filebilir oldu\u011funu g\u00f6sterir. <code>time<\/code> de\u011feri, sunucuya gidi\u015f-d\u00f6n\u00fc\u015f s\u00fcresini (gecikme) g\u00f6sterir.<\/p>\n<p><strong>Ba\u015far\u0131s\u0131z Ping Yan\u0131t\u0131:<\/strong><\/p>\n<p>E\u011fer ping komutu ba\u015far\u0131s\u0131z olursa, \u015funa benzer bir \u00e7\u0131kt\u0131 g\u00f6receksiniz:<\/p>\n<pre><code>Request <span class=\"hljs-keyword\">timeout<\/span> <span class=\"hljs-keyword\">for<\/span> icmp_seq <span class=\"hljs-number\">1<\/span>\r\nRequest <span class=\"hljs-keyword\">timeout<\/span> <span class=\"hljs-keyword\">for<\/span> icmp_seq <span class=\"hljs-number\">2<\/span>\r\nRequest <span class=\"hljs-keyword\">timeout<\/span> <span class=\"hljs-keyword\">for<\/span> icmp_seq <span class=\"hljs-number\">3<\/span>\r\n<\/code><\/pre>\n<p>Veya:<\/p>\n<pre><code>pin<span class=\"hljs-variable\">g:<\/span> cannot <span class=\"hljs-built_in\">resolve<\/span> example.<span class=\"hljs-keyword\">com<\/span>: Unknown host\r\n<\/code><\/pre>\n<p>Bu, sunucunun \u00e7evrimi\u00e7i olmad\u0131\u011f\u0131n\u0131 veya a\u011f\u0131n\u0131zdan eri\u015filemedi\u011fini g\u00f6sterir. Olas\u0131 nedenler \u015funlard\u0131r:<\/p>\n<ul>\n<li><strong>Sunucu Kapal\u0131:<\/strong> Sunucu kapal\u0131 veya bak\u0131mda olabilir.<\/li>\n<li><strong>A\u011f Problemi:<\/strong> Sunucuya giden a\u011f yolunda bir sorun olabilir.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131:<\/strong> Sunucu taraf\u0131nda veya a\u011f\u0131n\u0131zda bir g\u00fcvenlik duvar\u0131, ping isteklerini engelliyor olabilir.<\/li>\n<li><strong>DNS Sorunu:<\/strong> Sunucu ad\u0131n\u0131 IP adresine \u00e7\u00f6z\u00fcmleyemiyor olabilirsiniz (a\u015fa\u011f\u0131daki DNS \u00e7\u00f6z\u00fcmleme sorunlar\u0131 b\u00f6l\u00fcm\u00fcne bak\u0131n).<\/li>\n<\/ul>\n<\/li>\n<li><strong>DNS \u00c7\u00f6z\u00fcmleme Sorunlar\u0131n\u0131 Kontrol Etme:<\/strong>DNS (Domain Name System), alan adlar\u0131n\u0131 (\u00f6rne\u011fin, example.com) IP adreslerine (\u00f6rne\u011fin, 93.184.216.34) d\u00f6n\u00fc\u015ft\u00fcren bir sistemdir. E\u011fer DNS \u00e7\u00f6z\u00fcmleme sorunlar\u0131 ya\u015f\u0131yorsan\u0131z, sunucu ad\u0131na g\u00f6re ba\u011flanmaya \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131zda sorunlarla kar\u015f\u0131la\u015fabilirsiniz.\n<p><strong>DNS Sorunu Belirtileri:<\/strong><\/p>\n<ul>\n<li>Ping komutu, sunucu ad\u0131n\u0131 IP adresine \u00e7\u00f6z\u00fcmleyemiyor ve &#8220;Unknown host&#8221; hatas\u0131 veriyor.<\/li>\n<li>Web taray\u0131c\u0131n\u0131zda bir web sitesine eri\u015fmeye \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131zda, &#8220;Sunucu bulunamad\u0131&#8221; veya benzeri bir hata mesaj\u0131 g\u00f6r\u00fcyorsunuz.<\/li>\n<\/ul>\n<p><strong>DNS Sorunlar\u0131n\u0131 Giderme:<\/strong><\/p>\n<ul>\n<li><strong>DNS Sunucular\u0131n\u0131 Kontrol Etme:<\/strong> \u0130\u015fletim sisteminizin a\u011f ayarlar\u0131nda yap\u0131land\u0131r\u0131lm\u0131\u015f DNS sunucular\u0131n\u0131 kontrol edin. Genellikle, internet servis sa\u011flay\u0131c\u0131n\u0131z (ISP) taraf\u0131ndan sa\u011flanan DNS sunucular\u0131 kullan\u0131l\u0131r. Ancak, Google Public DNS (8.8.8.8 ve 8.8.4.4) veya Cloudflare DNS (1.1.1.1 ve 1.0.0.1) gibi alternatif DNS sunucular\u0131n\u0131 kullanmay\u0131 deneyebilirsiniz.\n<ul>\n<li><strong>Windows:<\/strong> Denetim Masas\u0131 &gt; A\u011f ve \u0130nternet &gt; A\u011f ve Payla\u015f\u0131m Merkezi &gt; Ba\u011fda\u015ft\u0131r\u0131c\u0131 Ayarlar\u0131n\u0131 De\u011fi\u015ftir&#8217;e gidin. Ba\u011flant\u0131n\u0131z\u0131 (\u00f6rne\u011fin, Ethernet veya Wi-Fi) sa\u011f t\u0131klay\u0131n ve \u00d6zellikler&#8217;i se\u00e7in. \u0130nternet Protokol\u00fc S\u00fcr\u00fcm 4 (TCP\/IPv4)&#8217;\u00fc se\u00e7in ve \u00d6zellikler&#8217;e t\u0131klay\u0131n. &#8220;A\u015fa\u011f\u0131daki DNS sunucu adreslerini kullan&#8221; se\u00e7ene\u011fini i\u015faretleyin ve tercih etti\u011finiz DNS sunucu adreslerini girin.<\/li>\n<li><strong>macOS:<\/strong> Sistem Tercihleri &gt; A\u011f&#8217;a gidin. Ba\u011flant\u0131n\u0131z\u0131 se\u00e7in ve \u0130leri D\u00fczey&#8217;e t\u0131klay\u0131n. DNS sekmesine gidin ve DNS sunucu adreslerini ekleyin veya d\u00fczenleyin.<\/li>\n<li><strong>Linux:<\/strong> A\u011f ayarlar\u0131n\u0131z, da\u011f\u0131t\u0131m\u0131n\u0131za ve a\u011f y\u00f6neticinize (\u00f6rne\u011fin, NetworkManager) ba\u011fl\u0131 olarak de\u011fi\u015fir. Genellikle, a\u011f ayarlar\u0131n\u0131z\u0131 yap\u0131land\u0131rmak i\u00e7in bir grafik aray\u00fcz\u00fc veya komut sat\u0131r\u0131 ara\u00e7lar\u0131 kullanabilirsiniz.<\/li>\n<\/ul>\n<\/li>\n<li><strong><code>nslookup<\/code> Komutu:<\/strong> <code>nslookup<\/code> komutu, bir alan ad\u0131n\u0131n IP adresini sorgulaman\u0131za olanak tan\u0131r. Komut sat\u0131r\u0131n\u0131 a\u00e7\u0131n ve a\u015fa\u011f\u0131daki komutu \u00e7al\u0131\u015ft\u0131r\u0131n:\n<pre><code class=\"lang-bash\">nslookup <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">sunucu_adresi<\/span>&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;sunucu_adresi&gt;<\/code> yerine, sorgulamak istedi\u011finiz alan ad\u0131n\u0131 (\u00f6rne\u011fin, example.com) yaz\u0131n.<\/p>\n<p>E\u011fer <code>nslookup<\/code> komutu ba\u015far\u0131l\u0131 bir \u015fekilde yan\u0131t veriyorsa, \u015funa benzer bir \u00e7\u0131kt\u0131 g\u00f6receksiniz:<\/p>\n<pre><code><span class=\"hljs-attribute\">Server<\/span>:  &lt;DNS_sunucusu_adresi&gt;\r\n<span class=\"hljs-attribute\">Address<\/span>:  &lt;DNS_sunucusu_IP_adresi&gt;\r\n\r\n<span class=\"css\"><span class=\"hljs-selector-tag\">Non-authoritative<\/span> <span class=\"hljs-selector-tag\">answer<\/span>:\r\n<span class=\"hljs-selector-tag\">Name<\/span>:    <span class=\"hljs-selector-tag\">example<\/span><span class=\"hljs-selector-class\">.com<\/span>\r\n<span class=\"hljs-selector-tag\">Address<\/span>:  93<span class=\"hljs-selector-class\">.184<\/span><span class=\"hljs-selector-class\">.216<\/span><span class=\"hljs-selector-class\">.34<\/span><\/span>\r\n<\/code><\/pre>\n<p>Bu, DNS \u00e7\u00f6z\u00fcmlemesinin ba\u015far\u0131l\u0131 oldu\u011funu g\u00f6sterir.<\/p>\n<p>E\u011fer <code>nslookup<\/code> komutu ba\u015far\u0131s\u0131z olursa, &#8220;server can&#8217;t find example.com: NXDOMAIN&#8221; veya benzeri bir hata mesaj\u0131 g\u00f6receksiniz. Bu, DNS \u00e7\u00f6z\u00fcmlemesinde bir sorun oldu\u011funu g\u00f6sterir.<\/li>\n<li><strong><code>dig<\/code> Komutu:<\/strong> <code>dig<\/code> komutu, <code>nslookup<\/code> komutuna benzer \u015fekilde DNS sorgular\u0131 yapman\u0131za olanak tan\u0131r, ancak daha ayr\u0131nt\u0131l\u0131 bilgi sa\u011flar. Komut sat\u0131r\u0131n\u0131 a\u00e7\u0131n ve a\u015fa\u011f\u0131daki komutu \u00e7al\u0131\u015ft\u0131r\u0131n:\n<pre><code class=\"lang-bash\"><span class=\"hljs-keyword\">dig<\/span> <span class=\"hljs-symbol\">&lt;sunucu_adresi&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;sunucu_adresi&gt;<\/code> yerine, sorgulamak istedi\u011finiz alan ad\u0131n\u0131 (\u00f6rne\u011fin, example.com) yaz\u0131n.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Yerel A\u011f (LAN) Ba\u011flant\u0131s\u0131n\u0131 Kontrol Etme (E\u011fer Ge\u00e7erliyse):<\/strong>E\u011fer sunucuya yerel a\u011f \u00fczerinden ba\u011flanmaya \u00e7al\u0131\u015f\u0131yorsan\u0131z, yerel a\u011f ba\u011flant\u0131n\u0131z\u0131n d\u00fczg\u00fcn \u00e7al\u0131\u015ft\u0131\u011f\u0131ndan emin olman\u0131z gerekir.\n<ul>\n<li><strong>Kablolu Ba\u011flant\u0131:<\/strong> Ethernet kablosunun hem bilgisayar\u0131n\u0131za hem de a\u011f cihaz\u0131na (\u00f6rne\u011fin, modem, y\u00f6nlendirici) s\u0131k\u0131ca tak\u0131l\u0131 oldu\u011fundan emin olun. Kabloda herhangi bir hasar olup olmad\u0131\u011f\u0131n\u0131 kontrol edin.<\/li>\n<li><strong>Kablosuz Ba\u011flant\u0131:<\/strong> Wi-Fi ba\u011flant\u0131n\u0131z\u0131n aktif ve g\u00fc\u00e7l\u00fc oldu\u011fundan emin olun. Do\u011fru Wi-Fi a\u011f\u0131na ba\u011fl\u0131 oldu\u011funuzu ve \u015fifreyi do\u011fru girdi\u011finizden emin olun.<\/li>\n<li><strong>A\u011f Cihazlar\u0131n\u0131 Yeniden Ba\u015flatma:<\/strong> Modem ve y\u00f6nlendiricinizi yeniden ba\u015flatmay\u0131 deneyin. Bu, baz\u0131 a\u011f sorunlar\u0131n\u0131 \u00e7\u00f6zebilir.<\/li>\n<li><strong>Yerel A\u011fda Ping Testi:<\/strong> Yerel a\u011fdaki ba\u015fka bir cihaza ping atmay\u0131 deneyin. Bu, yerel a\u011f\u0131n\u0131zda bir sorun olup olmad\u0131\u011f\u0131n\u0131 belirlemenize yard\u0131mc\u0131 olabilir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>2. SSH Sunucusunun Durumunu Kontrol Etmek<\/strong><\/p>\n<p>A\u011f ba\u011flant\u0131n\u0131z\u0131n sa\u011fl\u0131kl\u0131 oldu\u011fundan emin olduktan sonra, SSH sunucusunun d\u00fczg\u00fcn \u00e7al\u0131\u015ft\u0131\u011f\u0131ndan emin olman\u0131z gerekir.<\/p>\n<ul>\n<li><strong>SSH Sunucusunun \u00c7al\u0131\u015f\u0131r Durumda Olup Olmad\u0131\u011f\u0131n\u0131 Kontrol Etme (systemctl status sshd):<\/strong>SSH sunucusunun \u00e7al\u0131\u015f\u0131r durumda olup olmad\u0131\u011f\u0131n\u0131 kontrol etmek i\u00e7in, sunucuya ba\u011flanman\u0131z ve a\u015fa\u011f\u0131daki komutu \u00e7al\u0131\u015ft\u0131rman\u0131z gerekir (e\u011fer sunucuya eri\u015fiminiz varsa):\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">systemctl status sshd<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, SSH sunucusunun (sshd) durumunu g\u00f6sterir.<\/p>\n<p><strong>\u00c7al\u0131\u015f\u0131r Durumda:<\/strong><\/p>\n<p>E\u011fer SSH sunucusu \u00e7al\u0131\u015f\u0131yorsa, \u015funa benzer bir \u00e7\u0131kt\u0131 g\u00f6receksiniz:<\/p>\n<pre><code>\u25cf <span class=\"hljs-selector-tag\">ssh<\/span><span class=\"hljs-selector-class\">.service<\/span> <span class=\"hljs-selector-tag\">-<\/span> <span class=\"hljs-selector-tag\">OpenBSD<\/span> <span class=\"hljs-selector-tag\">Secure<\/span> <span class=\"hljs-selector-tag\">Shell<\/span> <span class=\"hljs-selector-tag\">server<\/span>\r\n     <span class=\"hljs-selector-tag\">Loaded<\/span>: <span class=\"hljs-selector-tag\">loaded<\/span> (\/lib\/systemd\/system\/ssh.service; enabled; vendor <span class=\"hljs-attribute\">preset<\/span>: enabled)\r\n     <span class=\"hljs-selector-tag\">Active<\/span>: <span class=\"hljs-selector-tag\">active<\/span> (running) <span class=\"hljs-selector-tag\">since<\/span> <span class=\"hljs-selector-tag\">Sat<\/span> <span class=\"hljs-selector-tag\">2023-10-28<\/span> <span class=\"hljs-selector-tag\">10<\/span><span class=\"hljs-selector-pseudo\">:00<\/span><span class=\"hljs-selector-pseudo\">:00<\/span> <span class=\"hljs-selector-tag\">UTC<\/span>; <span class=\"hljs-selector-tag\">1h<\/span> <span class=\"hljs-selector-tag\">30min<\/span> <span class=\"hljs-selector-tag\">ago<\/span>\r\n       <span class=\"hljs-selector-tag\">Docs<\/span>: <span class=\"hljs-selector-tag\">man<\/span><span class=\"hljs-selector-pseudo\">:sshd(8)<\/span>\r\n             <span class=\"hljs-selector-tag\">man<\/span><span class=\"hljs-selector-pseudo\">:sshd_config(5)<\/span>\r\n   <span class=\"hljs-selector-tag\">Main<\/span> <span class=\"hljs-selector-tag\">PID<\/span>: <span class=\"hljs-selector-tag\">1234<\/span> (sshd)\r\n      <span class=\"hljs-selector-tag\">Tasks<\/span>: <span class=\"hljs-selector-tag\">1<\/span> (<span class=\"hljs-attribute\">limit<\/span>: <span class=\"hljs-number\">4915<\/span>)\r\n     <span class=\"hljs-selector-tag\">CGroup<\/span>: \/<span class=\"hljs-selector-tag\">system<\/span><span class=\"hljs-selector-class\">.slice<\/span>\/<span class=\"hljs-selector-tag\">ssh<\/span><span class=\"hljs-selector-class\">.service<\/span>\r\n             \u2514\u2500<span class=\"hljs-selector-tag\">1234<\/span> \/<span class=\"hljs-selector-tag\">usr<\/span>\/<span class=\"hljs-selector-tag\">sbin<\/span>\/<span class=\"hljs-selector-tag\">sshd<\/span> <span class=\"hljs-selector-tag\">-D<\/span>\r\n<\/code><\/pre>\n<p><code>Active: active (running)<\/code> sat\u0131r\u0131, SSH sunucusunun \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131 g\u00f6sterir.<\/p>\n<p><strong>\u00c7al\u0131\u015fm\u0131yor Durumda:<\/strong><\/p>\n<p>E\u011fer SSH sunucusu \u00e7al\u0131\u015fm\u0131yorsa, \u015funa benzer bir \u00e7\u0131kt\u0131 g\u00f6receksiniz:<\/p>\n<pre><code>\u25cf <span class=\"hljs-selector-tag\">ssh<\/span><span class=\"hljs-selector-class\">.service<\/span> <span class=\"hljs-selector-tag\">-<\/span> <span class=\"hljs-selector-tag\">OpenBSD<\/span> <span class=\"hljs-selector-tag\">Secure<\/span> <span class=\"hljs-selector-tag\">Shell<\/span> <span class=\"hljs-selector-tag\">server<\/span>\r\n     <span class=\"hljs-selector-tag\">Loaded<\/span>: <span class=\"hljs-selector-tag\">loaded<\/span> (\/lib\/systemd\/system\/ssh.service; enabled; vendor <span class=\"hljs-attribute\">preset<\/span>: enabled)\r\n     <span class=\"hljs-selector-tag\">Active<\/span>: <span class=\"hljs-selector-tag\">inactive<\/span> (dead) <span class=\"hljs-selector-tag\">since<\/span> <span class=\"hljs-selector-tag\">Sat<\/span> <span class=\"hljs-selector-tag\">2023-10-28<\/span> <span class=\"hljs-selector-tag\">08<\/span><span class=\"hljs-selector-pseudo\">:30<\/span><span class=\"hljs-selector-pseudo\">:00<\/span> <span class=\"hljs-selector-tag\">UTC<\/span>; <span class=\"hljs-selector-tag\">3h<\/span> <span class=\"hljs-selector-tag\">0min<\/span> <span class=\"hljs-selector-tag\">ago<\/span>\r\n       <span class=\"hljs-selector-tag\">Docs<\/span>: <span class=\"hljs-selector-tag\">man<\/span><span class=\"hljs-selector-pseudo\">:sshd(8)<\/span>\r\n             <span class=\"hljs-selector-tag\">man<\/span><span class=\"hljs-selector-pseudo\">:sshd_config(5)<\/span>\r\n<\/code><\/pre>\n<p><code>Active: inactive (dead)<\/code> sat\u0131r\u0131, SSH sunucusunun \u00e7al\u0131\u015fmad\u0131\u011f\u0131n\u0131 g\u00f6sterir.<\/p>\n<p>E\u011fer SSH sunucusu \u00e7al\u0131\u015fm\u0131yorsa, a\u015fa\u011f\u0131daki komutla ba\u015flatabilirsiniz:<\/p>\n<pre><code class=\"lang-bash\">sudo systemctl <span class=\"hljs-literal\">start<\/span> sshd\r\n<\/code><\/pre>\n<p>Ve ba\u015flat\u0131ld\u0131ktan sonra, durumunu tekrar kontrol edin.<\/li>\n<li><strong>SSH Sunucu G\u00fcnl\u00fcklerini (Logs) \u0130nceleyerek Hata Mesajlar\u0131n\u0131 Belirleme:<\/strong>SSH sunucusunun g\u00fcnl\u00fckleri, ba\u011flant\u0131 sorunlar\u0131n\u0131n nedenlerini belirlemenize yard\u0131mc\u0131 olabilir. G\u00fcnl\u00fckler, sunucu taraf\u0131nda kaydedilen olaylar\u0131 ve hatalar\u0131 i\u00e7erir.\n<p><strong>G\u00fcnl\u00fck Dosyalar\u0131n\u0131n Konumu:<\/strong><\/p>\n<p>SSH sunucu g\u00fcnl\u00fcklerinin konumu, i\u015fletim sistemine ve yap\u0131land\u0131rmaya ba\u011fl\u0131 olarak de\u011fi\u015fir. \u0130\u015fte baz\u0131 yayg\u0131n konumlar:<\/p>\n<ul>\n<li><strong>Debian\/Ubuntu:<\/strong> <code>\/var\/log\/auth.log<\/code> veya <code>\/var\/log\/syslog<\/code><\/li>\n<li><strong>CentOS\/RHEL:<\/strong> <code>\/var\/log\/secure<\/code><\/li>\n<li><strong>macOS:<\/strong> <code>\/var\/log\/system.log<\/code> (Konsol uygulamas\u0131 arac\u0131l\u0131\u011f\u0131yla g\u00f6r\u00fcnt\u00fclenebilir)<\/li>\n<\/ul>\n<p><strong>G\u00fcnl\u00fckleri \u0130nceleme:<\/strong><\/p>\n<p>G\u00fcnl\u00fckleri incelemek i\u00e7in, komut sat\u0131r\u0131n\u0131 a\u00e7\u0131n ve <code>cat<\/code>, <code>less<\/code>, <code>grep<\/code> gibi komutlar\u0131 kullanabilirsiniz. \u00d6rne\u011fin, <code>\/var\/log\/auth.log<\/code> dosyas\u0131n\u0131 incelemek i\u00e7in a\u015fa\u011f\u0131daki komutu kullanabilirsiniz:<\/p>\n<pre><code class=\"lang-bash\">sudo <span class=\"hljs-keyword\">cat<\/span> \/<span class=\"hljs-keyword\">var<\/span>\/<span class=\"hljs-keyword\">log<\/span>\/auth.<span class=\"hljs-keyword\">log<\/span> | less\r\n<\/code><\/pre>\n<p>Bu komut, g\u00fcnl\u00fck dosyas\u0131n\u0131n i\u00e7eri\u011fini g\u00f6r\u00fcnt\u00fcler ve <code>less<\/code> komutuyla sayfalar aras\u0131nda gezinebilirsiniz.<\/p>\n<p><strong>Hata Mesajlar\u0131n\u0131 Arama:<\/strong><\/p>\n<p>G\u00fcnl\u00fcklerde hata mesajlar\u0131n\u0131 aramak i\u00e7in <code>grep<\/code> komutunu kullanabilirsiniz. \u00d6rne\u011fin, &#8220;Failed password&#8221; (Ba\u015far\u0131s\u0131z parola) hatalar\u0131n\u0131 aramak i\u00e7in a\u015fa\u011f\u0131daki komutu kullanabilirsiniz:<\/p>\n<pre><code class=\"lang-bash\">sudo grep <span class=\"hljs-string\">\"Failed password\"<\/span> \/<span class=\"hljs-built_in\">var<\/span>\/<span class=\"hljs-keyword\">log<\/span>\/auth.<span class=\"hljs-keyword\">log<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, g\u00fcnl\u00fck dosyas\u0131nda &#8220;Failed password&#8221; ifadesini i\u00e7eren sat\u0131rlar\u0131 g\u00f6r\u00fcnt\u00fcler. Bu, kimlik do\u011frulama sorunlar\u0131n\u0131 belirlemenize yard\u0131mc\u0131 olabilir.<\/p>\n<p><strong>\u00d6nemli G\u00fcnl\u00fck Mesajlar\u0131:<\/strong><\/p>\n<p>\u0130\u015fte SSH sunucu g\u00fcnl\u00fcklerinde s\u0131k\u00e7a kar\u015f\u0131la\u015f\u0131lan baz\u0131 \u00f6nemli mesajlar:<\/p>\n<ul>\n<li><strong>Failed password:<\/strong> Ba\u015far\u0131s\u0131z parola denemesi.<\/li>\n<li><strong>Invalid user:<\/strong> Ge\u00e7ersiz kullan\u0131c\u0131 ad\u0131.<\/li>\n<li><strong>Connection closed by:<\/strong> Ba\u011flant\u0131 kapat\u0131ld\u0131.<\/li>\n<li><strong>Accepted publickey for:<\/strong> Ba\u015far\u0131l\u0131 anahtar tabanl\u0131 kimlik do\u011frulama.<\/li>\n<li><strong>Disconnected from invalid user:<\/strong> Ge\u00e7ersiz kullan\u0131c\u0131dan ba\u011flant\u0131 kesildi.<\/li>\n<li><strong>Received disconnect from:<\/strong> Uzak taraftan ba\u011flant\u0131 kesildi.<\/li>\n<li><strong>Did not receive identification string:<\/strong> \u0130stemciden kimlik bilgisi al\u0131namad\u0131.<\/li>\n<\/ul>\n<p>Bu mesajlar\u0131 inceleyerek, ba\u011flant\u0131 sorunlar\u0131n\u0131n nedenlerini belirleyebilir ve uygun \u00e7\u00f6z\u00fcmleri uygulayabilirsiniz.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 (Firewall) Ayarlar\u0131n\u0131 Kontrol Etme (ufw, iptables):<\/strong>G\u00fcvenlik duvar\u0131, a\u011f trafi\u011fini filtreleyen ve yetkisiz eri\u015fimi engelleyen bir g\u00fcvenlik mekanizmas\u0131d\u0131r. E\u011fer g\u00fcvenlik duvar\u0131 SSH trafi\u011fini engelliyorsa, ba\u011flant\u0131 sorunlar\u0131 ya\u015fayabilirsiniz.\n<p><strong>G\u00fcvenlik Duvar\u0131 Kontrol\u00fc:<\/strong><\/p>\n<p>G\u00fcvenlik duvar\u0131n\u0131n SSH trafi\u011fini engelleyip engellemedi\u011fini kontrol etmek i\u00e7in, g\u00fcvenlik duvar\u0131 yap\u0131land\u0131rman\u0131z\u0131 incelemeniz gerekir.<\/p>\n<p><strong>UFW (Uncomplicated Firewall):<\/strong><\/p>\n<p>UFW, Ubuntu ve Debian gibi sistemlerde yayg\u0131n olarak kullan\u0131lan kullan\u0131c\u0131 dostu bir g\u00fcvenlik duvar\u0131 arac\u0131d\u0131r. UFW&#8217;nin durumunu kontrol etmek i\u00e7in a\u015fa\u011f\u0131daki komutu kullanabilirsiniz:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo ufw status<\/span>\r\n<\/code><\/pre>\n<p>E\u011fer UFW aktifse, \u015funa benzer bir \u00e7\u0131kt\u0131 g\u00f6receksiniz:<\/p>\n<pre><code><span class=\"hljs-attribute\">Status<\/span>: active\r\n\r\n<span class=\"brainfuck\"><span class=\"hljs-comment\">To<\/span>                         <span class=\"hljs-comment\">Action<\/span>      <span class=\"hljs-comment\">From<\/span>\r\n<span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span>                         <span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span>      <span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span>\r\n<span class=\"hljs-comment\">22\/tcp<\/span>                     <span class=\"hljs-comment\">ALLOW<\/span>       <span class=\"hljs-comment\">Anywhere<\/span>\r\n<span class=\"hljs-comment\">22<\/span>                         <span class=\"hljs-comment\">ALLOW<\/span>       <span class=\"hljs-comment\">Anywhere<\/span><\/span>\r\n<\/code><\/pre>\n<p>Bu, 22 numaral\u0131 port \u00fczerinden SSH trafi\u011fine izin verildi\u011fini g\u00f6sterir. E\u011fer SSH trafi\u011fine izin verilmiyorsa, a\u015fa\u011f\u0131daki komutla izin verebilirsiniz:<\/p>\n<pre><code class=\"lang-bash\">sudo ufw allow 22\/tcp\r\nsudo ufw <span class=\"hljs-built_in\">enable<\/span>\r\n<\/code><\/pre>\n<p><strong>iptables:<\/strong><\/p>\n<p>iptables, Linux sistemlerde kullan\u0131lan daha karma\u015f\u0131k bir g\u00fcvenlik duvar\u0131 arac\u0131d\u0131r. iptables kurallar\u0131n\u0131 g\u00f6r\u00fcnt\u00fclemek i\u00e7in a\u015fa\u011f\u0131daki komutu kullanabilirsiniz:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo iptables -L<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, iptables kurallar\u0131n\u0131n bir listesini g\u00f6r\u00fcnt\u00fcler. SSH trafi\u011fini eng<\/li>\n<\/ul>\n<p>elliyen bir kural olup olmad\u0131\u011f\u0131n\u0131 kontrol edin. E\u011fer engelliyorsa, uygun bir kural ekleyerek SSH trafi\u011fine izin verebilirsiniz.<\/p>\n<p><strong>\u00d6rnek Senaryolar:<\/strong><\/p>\n<ul>\n<li><strong>Senaryo 1:<\/strong> Bir kullan\u0131c\u0131, sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak ba\u011flant\u0131 zaman a\u015f\u0131m\u0131na u\u011frar. Ping komutuyla sunucuya eri\u015filebildi\u011fini do\u011frular. Ard\u0131ndan, SSH sunucusunun durumunu kontrol eder ve sunucunun \u00e7al\u0131\u015fmad\u0131\u011f\u0131n\u0131 fark eder. <code>sudo systemctl start sshd<\/code> komutuyla sunucuyu ba\u015flat\u0131r ve ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/li>\n<li><strong>Senaryo 2:<\/strong> Bir sistem y\u00f6neticisi, bir sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak &#8220;Connection refused&#8221; hatas\u0131 al\u0131r. SSH sunucusunun \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131 do\u011frular. Ard\u0131ndan, <code>\/var\/log\/auth.log<\/code> dosyas\u0131n\u0131 inceler ve &#8220;Too many authentication failures&#8221; hatalar\u0131n\u0131 g\u00f6r\u00fcr. Bu, bir brute-force sald\u0131r\u0131s\u0131 giri\u015fimini g\u00f6sterir. Fail2ban gibi bir ara\u00e7 kullanarak sald\u0131r\u0131y\u0131 engeller ve ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/li>\n<li><strong>Senaryo 3:<\/strong> Bir geli\u015ftirici, bir sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak ba\u011flant\u0131 zaman a\u015f\u0131m\u0131na u\u011frar. Ping komutuyla sunucuya eri\u015filebildi\u011fini do\u011frular. Ard\u0131ndan, <code>sudo ufw status<\/code> komutuyla g\u00fcvenlik duvar\u0131 durumunu kontrol eder ve SSH trafi\u011finin engellendi\u011fini fark eder. <code>sudo ufw allow 22\/tcp<\/code> komutuyla SSH trafi\u011fine izin verir ve ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/li>\n<\/ul>\n<p>Bu temel kontroller ve ilk ad\u0131mlar, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap arayan kullan\u0131c\u0131lar i\u00e7in \u00f6nemli bir ba\u015flang\u0131\u00e7 noktas\u0131d\u0131r. A\u011f ba\u011flant\u0131s\u0131n\u0131n ve SSH sunucusunun durumunu kontrol etmek, sorunun kayna\u011f\u0131n\u0131 belirlemenize ve do\u011fru \u00e7\u00f6z\u00fcm\u00fc bulman\u0131za yard\u0131mc\u0131 olacakt\u0131r. Bir sonraki b\u00f6l\u00fcmde, kimlik do\u011frulama sorunlar\u0131 ve \u00e7\u00f6z\u00fcmlerini ele alaca\u011f\u0131z.<\/p>\n<h2 id=\"3-kimlik-do-rulama-authentication-problemleri-ve-z-mleri\"><span class=\"ez-toc-section\" id=\"3_Kimlik_Dogrulama_Authentication_Problemleri_ve_Cozumleri\"><\/span>3. Kimlik Do\u011frulama (Authentication) Problemleri ve \u00c7\u00f6z\u00fcmleri<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Kimlik do\u011frulama (authentication) problemleri, SSH ba\u011flant\u0131 sorunlar\u0131n\u0131n en s\u0131k kar\u015f\u0131la\u015f\u0131lan ve sinir bozucu olanlar\u0131ndan biridir. Bu problemler, yanl\u0131\u015f kullan\u0131c\u0131 ad\u0131 veya \u015fifre kullan\u0131m\u0131ndan, hatal\u0131 SSH anahtar\u0131 konfig\u00fcrasyonlar\u0131na kadar \u00e7e\u015fitli nedenlerden kaynaklanabilir. Bu b\u00f6l\u00fcm, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap arayan ve kimlik do\u011frulama sorunlar\u0131 ya\u015fayan kullan\u0131c\u0131lara kapsaml\u0131 bir rehber sunmaktad\u0131r. Kimlik do\u011frulama y\u00f6ntemlerini, olas\u0131 sorunlar\u0131 ve ad\u0131m ad\u0131m \u00e7\u00f6z\u00fcm \u00f6nerilerini detayl\u0131 bir \u015fekilde inceleyece\u011fiz.<\/p>\n<p><strong>Kimlik Do\u011frulama Y\u00f6ntemleri: Genel Bir Bak\u0131\u015f<\/strong><\/p>\n<p>SSH, kullan\u0131c\u0131lar\u0131n kimli\u011fini do\u011frulamak i\u00e7in \u00e7e\u015fitli y\u00f6ntemler sunar. Bu y\u00f6ntemler, g\u00fcvenlik seviyeleri ve kullan\u0131m kolayl\u0131\u011f\u0131 a\u00e7\u0131s\u0131ndan farkl\u0131l\u0131k g\u00f6sterir. En yayg\u0131n kullan\u0131lan kimlik do\u011frulama y\u00f6ntemleri \u015funlard\u0131r:<\/p>\n<ul>\n<li><strong>Parola Tabanl\u0131 Kimlik Do\u011frulama:<\/strong> En basit ve en yayg\u0131n kullan\u0131lan y\u00f6ntemdir. Kullan\u0131c\u0131, kullan\u0131c\u0131 ad\u0131 ve \u015fifre kombinasyonu ile oturum a\u00e7ar.<\/li>\n<li><strong>SSH Anahtar\u0131 Tabanl\u0131 Kimlik Do\u011frulama:<\/strong> Daha g\u00fcvenli bir y\u00f6ntemdir. Kullan\u0131c\u0131, bir \u00f6zel anahtar (private key) ve bir genel anahtar (public key) \u00e7ifti kullan\u0131r. \u00d6zel anahtar, kullan\u0131c\u0131n\u0131n bilgisayar\u0131nda saklan\u0131r ve genel anahtar, sunucuda <code>authorized_keys<\/code> dosyas\u0131na eklenir.<\/li>\n<li><strong>\u00c7ok Fakt\u00f6rl\u00fc Kimlik Do\u011frulama (MFA):<\/strong> En g\u00fcvenli y\u00f6ntemdir. Kullan\u0131c\u0131, birden fazla kimlik do\u011frulama fakt\u00f6r\u00fc (\u00f6rne\u011fin, parola ve tek kullan\u0131ml\u0131k kod) kullanarak oturum a\u00e7ar.<\/li>\n<\/ul>\n<p><strong>Parola Tabanl\u0131 Kimlik Do\u011frulama Sorunlar\u0131 ve \u00c7\u00f6z\u00fcmleri<\/strong><\/p>\n<p>Parola tabanl\u0131 kimlik do\u011frulama, kullan\u0131m kolayl\u0131\u011f\u0131 nedeniyle pop\u00fcler olsa da, g\u00fcvenlik a\u00e7\u0131klar\u0131 nedeniyle riskli olabilir. Brute-force sald\u0131r\u0131lar\u0131, parola tahmin etme y\u00f6ntemleri ve kimlik av\u0131 sald\u0131r\u0131lar\u0131, parola tabanl\u0131 kimlik do\u011frulaman\u0131n zay\u0131f noktalar\u0131d\u0131r. <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken, parola tabanl\u0131 kimlik do\u011frulama sorunlar\u0131n\u0131 anlamak ve gidermek \u00f6nemlidir.<\/p>\n<ul>\n<li><strong>Yanl\u0131\u015f Kullan\u0131c\u0131 Ad\u0131 veya \u015eifre Sorunlar\u0131:<\/strong>En basit ve en s\u0131k kar\u015f\u0131la\u015f\u0131lan sorun, yanl\u0131\u015f kullan\u0131c\u0131 ad\u0131 veya \u015fifre girmektir. Bu, yaz\u0131m hatalar\u0131ndan, Caps Lock tu\u015funun a\u00e7\u0131k unutulmas\u0131ndan veya yanl\u0131\u015f \u015fifre hat\u0131rlamaktan kaynaklanabilir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong>Kullan\u0131c\u0131 Ad\u0131n\u0131 Do\u011frulama:<\/strong> Kullan\u0131c\u0131 ad\u0131n\u0131n do\u011fru yaz\u0131ld\u0131\u011f\u0131ndan emin olun. B\u00fcy\u00fck\/k\u00fc\u00e7\u00fck harf duyarl\u0131l\u0131\u011f\u0131n\u0131 kontrol edin.<\/li>\n<li><strong>\u015eifreyi Do\u011frulama:<\/strong> \u015eifrenin do\u011fru yaz\u0131ld\u0131\u011f\u0131ndan emin olun. Caps Lock tu\u015funun kapal\u0131 oldu\u011fundan emin olun.<\/li>\n<li><strong>\u015eifre S\u0131f\u0131rlama:<\/strong> E\u011fer \u015fifreyi unuttuysan\u0131z, \u015fifre s\u0131f\u0131rlama y\u00f6ntemlerini kullan\u0131n. Sunucuya eri\u015fiminiz varsa, a\u015fa\u011f\u0131daki ad\u0131mlar\u0131 izleyebilirsiniz:\n<ul>\n<li><strong>Sunucuda \u015eifre S\u0131f\u0131rlama:<\/strong> Sunucuya ba\u011flan\u0131n (e\u011fer m\u00fcmk\u00fcnse ba\u015fka bir kullan\u0131c\u0131 ile) ve a\u015fa\u011f\u0131daki komutu kullanarak \u015fifreyi s\u0131f\u0131rlay\u0131n:\n<pre><code class=\"lang-bash\">sudo passwd <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">kullanici_adi<\/span>&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;kullanici_adi&gt;<\/code> yerine, \u015fifresini s\u0131f\u0131rlamak istedi\u011finiz kullan\u0131c\u0131n\u0131n ad\u0131n\u0131 yaz\u0131n. Komut, sizden yeni bir \u015fifre girmenizi isteyecektir.<\/li>\n<li><strong>Kurtarma Modu:<\/strong> E\u011fer sunucuya eri\u015fiminiz yoksa, kurtarma modunu kullanarak \u015fifreyi s\u0131f\u0131rlayabilirsiniz. Bu y\u00f6ntem, sunucunun fiziksel eri\u015fimini veya bir kurtarma diskini gerektirebilir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong><code>PasswordAuthentication<\/code> Devre D\u0131\u015f\u0131:<\/strong>G\u00fcvenlik nedeniyle, baz\u0131 sistem y\u00f6neticileri SSH sunucusunda parola tabanl\u0131 kimlik do\u011frulamay\u0131 devre d\u0131\u015f\u0131 b\u0131rak\u0131r. Bu durumda, kullan\u0131c\u0131lar\u0131n SSH anahtar\u0131 tabanl\u0131 kimlik do\u011frulama kullanmas\u0131 gerekir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong><code>sshd_config<\/code> Dosyas\u0131n\u0131 Kontrol Etme:<\/strong> Sunucuya eri\u015fiminiz varsa, SSH sunucu yap\u0131land\u0131rma dosyas\u0131n\u0131 (<code>sshd_config<\/code>) kontrol edin ve <code>PasswordAuthentication<\/code> se\u00e7ene\u011finin de\u011ferini kontrol edin.\n<pre><code class=\"lang-bash\">sudo nano <span class=\"hljs-regexp\">\/etc\/<\/span>ssh<span class=\"hljs-regexp\">\/sshd_config<\/span>\r\n<\/code><\/pre>\n<p>Dosyada a\u015fa\u011f\u0131daki sat\u0131r\u0131 aray\u0131n:<\/p>\n<pre><code><span class=\"hljs-attribute\">PasswordAuthentication<\/span> <span class=\"hljs-literal\">no<\/span>\r\n<\/code><\/pre>\n<p>E\u011fer <code>PasswordAuthentication no<\/code> ise, parola tabanl\u0131 kimlik do\u011frulama devre d\u0131\u015f\u0131d\u0131r. E\u011fer etkinle\u015ftirmek istiyorsan\u0131z, <code>yes<\/code> olarak de\u011fi\u015ftirin:<\/p>\n<pre><code><span class=\"hljs-attribute\">PasswordAuthentication<\/span> <span class=\"hljs-literal\">yes<\/span>\r\n<\/code><\/pre>\n<p>De\u011fi\u015fiklikleri kaydettikten sonra, SSH servisini yeniden ba\u015flat\u0131n:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo systemctl restart sshd<\/span>\r\n<\/code><\/pre>\n<p><strong>Uyar\u0131:<\/strong> Parola tabanl\u0131 kimlik do\u011frulamay\u0131 etkinle\u015ftirmek, sunucunuzun g\u00fcvenli\u011fini azaltabilir. Bu nedenle, dikkatli olun ve g\u00fcvenlik \u00f6nlemlerinizi g\u00f6zden ge\u00e7irin.<\/li>\n<li><strong>SSH Anahtar\u0131 Tabanl\u0131 Kimlik Do\u011frulama:<\/strong> Parola tabanl\u0131 kimlik do\u011frulama devre d\u0131\u015f\u0131ysa, SSH anahtar\u0131 tabanl\u0131 kimlik do\u011frulama kullanman\u0131z gerekir (a\u015fa\u011f\u0131daki b\u00f6l\u00fcme bak\u0131n).<\/li>\n<\/ul>\n<\/li>\n<li><strong><code>PermitRootLogin<\/code> K\u0131s\u0131tlamalar\u0131:<\/strong>G\u00fcvenlik nedeniyle, baz\u0131 sistem y\u00f6neticileri root kullan\u0131c\u0131s\u0131n\u0131n do\u011frudan SSH \u00fczerinden oturum a\u00e7mas\u0131n\u0131 engeller. Bu durumda, kullan\u0131c\u0131lar\u0131n \u00f6nce normal bir kullan\u0131c\u0131 ile oturum a\u00e7mas\u0131 ve ard\u0131ndan <code>sudo<\/code> komutunu kullanarak root yetkilerine y\u00fckseltmesi gerekir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong><code>sshd_config<\/code> Dosyas\u0131n\u0131 Kontrol Etme:<\/strong> Sunucuya eri\u015fiminiz varsa, SSH sunucu yap\u0131land\u0131rma dosyas\u0131n\u0131 (<code>sshd_config<\/code>) kontrol edin ve <code>PermitRootLogin<\/code> se\u00e7ene\u011finin de\u011ferini kontrol edin.\n<pre><code class=\"lang-bash\">sudo nano <span class=\"hljs-regexp\">\/etc\/<\/span>ssh<span class=\"hljs-regexp\">\/sshd_config<\/span>\r\n<\/code><\/pre>\n<p>Dosyada a\u015fa\u011f\u0131daki sat\u0131r\u0131 aray\u0131n:<\/p>\n<pre><code><span class=\"hljs-attribute\">PermitRootLogin<\/span> <span class=\"hljs-literal\">no<\/span>\r\n<\/code><\/pre>\n<p>E\u011fer <code>PermitRootLogin no<\/code> ise, root kullan\u0131c\u0131s\u0131n\u0131n do\u011frudan oturum a\u00e7mas\u0131 engellenmi\u015ftir. E\u011fer etkinle\u015ftirmek istiyorsan\u0131z, <code>yes<\/code> olarak de\u011fi\u015ftirin:<\/p>\n<pre><code><span class=\"hljs-attribute\">PermitRootLogin<\/span> <span class=\"hljs-literal\">yes<\/span>\r\n<\/code><\/pre>\n<p>De\u011fi\u015fiklikleri kaydettikten sonra, SSH servisini yeniden ba\u015flat\u0131n:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo systemctl restart sshd<\/span>\r\n<\/code><\/pre>\n<p><strong>Uyar\u0131:<\/strong> Root kullan\u0131c\u0131s\u0131n\u0131n do\u011frudan oturum a\u00e7mas\u0131na izin vermek, sunucunuzun g\u00fcvenli\u011fini azaltabilir. Bu nedenle, dikkatli olun ve g\u00fcvenlik \u00f6nlemlerinizi g\u00f6zden ge\u00e7irin.<\/li>\n<li><strong>Normal Kullan\u0131c\u0131 ile Oturum A\u00e7ma:<\/strong> Root kullan\u0131c\u0131s\u0131 ile do\u011frudan oturum a\u00e7mak yerine, normal bir kullan\u0131c\u0131 ile oturum a\u00e7\u0131n ve ard\u0131ndan <code>sudo<\/code> komutunu kullanarak root yetkilerine y\u00fckseltin:\n<pre><code class=\"lang-bash\">ssh <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">normal_kullanici_adi<\/span>&gt;<\/span>@<span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">sunucu_adresi<\/span>&gt;<\/span>\r\nsudo su -\r\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong><code>MaxAuthTries<\/code> S\u0131n\u0131r\u0131:<\/strong>SSH sunucusu, brute-force sald\u0131r\u0131lar\u0131n\u0131 \u00f6nlemek i\u00e7in, belirli bir s\u00fcre i\u00e7inde izin verilen maksimum kimlik do\u011frulama denemesi say\u0131s\u0131n\u0131 s\u0131n\u0131rlar. E\u011fer \u00e7ok fazla yanl\u0131\u015f parola denemesi yaparsan\u0131z, ba\u011flant\u0131n\u0131z engellenebilir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong><code>sshd_config<\/code> Dosyas\u0131n\u0131 Kontrol Etme:<\/strong> Sunucuya eri\u015fiminiz varsa, SSH sunucu yap\u0131land\u0131rma dosyas\u0131n\u0131 (<code>sshd_config<\/code>) kontrol edin ve <code>MaxAuthTries<\/code> se\u00e7ene\u011finin de\u011ferini kontrol edin.\n<pre><code class=\"lang-bash\">sudo nano <span class=\"hljs-regexp\">\/etc\/<\/span>ssh<span class=\"hljs-regexp\">\/sshd_config<\/span>\r\n<\/code><\/pre>\n<p>Dosyada a\u015fa\u011f\u0131daki sat\u0131r\u0131 aray\u0131n:<\/p>\n<pre><code>MaxAuthTries <span class=\"hljs-number\">6<\/span>\r\n<\/code><\/pre>\n<p>Bu, izin verilen maksimum kimlik do\u011frulama denemesi say\u0131s\u0131n\u0131n 6 oldu\u011funu g\u00f6sterir. E\u011fer bu say\u0131y\u0131 art\u0131rmak istiyorsan\u0131z, de\u011feri de\u011fi\u015ftirin:<\/p>\n<pre><code>MaxAuthTries <span class=\"hljs-number\">10<\/span>\r\n<\/code><\/pre>\n<p>De\u011fi\u015fiklikleri kaydettikten sonra, SSH servisini yeniden ba\u015flat\u0131n:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo systemctl restart sshd<\/span>\r\n<\/code><\/pre>\n<p><strong>Uyar\u0131:<\/strong> <code>MaxAuthTries<\/code> de\u011ferini \u00e7ok y\u00fcksek ayarlamak, sunucunuzu brute-force sald\u0131r\u0131lar\u0131na kar\u015f\u0131 daha savunmas\u0131z hale getirebilir.<\/li>\n<li><strong>Bekleme:<\/strong> E\u011fer ba\u011flant\u0131n\u0131z engellendiyse, bir s\u00fcre bekleyin ve tekrar deneyin. Engelleme s\u00fcresi, sunucu yap\u0131land\u0131rmas\u0131na ba\u011fl\u0131 olarak de\u011fi\u015febilir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>SSH Anahtar\u0131 Tabanl\u0131 Kimlik Do\u011frulama Sorunlar\u0131 ve \u00c7\u00f6z\u00fcmleri<\/strong><\/p>\n<p>SSH anahtar\u0131 tabanl\u0131 kimlik do\u011frulama, paroladan daha g\u00fcvenli bir y\u00f6ntemdir. Ancak, anahtar konfig\u00fcrasyonunda hatalar yap\u0131lmas\u0131 durumunda ba\u011flant\u0131 sorunlar\u0131na yol a\u00e7abilir. <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken, SSH anahtar\u0131 tabanl\u0131 kimlik do\u011frulama sorunlar\u0131n\u0131 anlamak ve gidermek \u00f6nemlidir.<\/p>\n<ul>\n<li><strong>\u00d6zel Anahtar\u0131n Do\u011fru Konumda ve \u0130zinlerde Olmad\u0131\u011f\u0131ndan Emin Olma (.ssh dizini):<\/strong>\u00d6zel anahtar, kullan\u0131c\u0131n\u0131n bilgisayar\u0131nda saklan\u0131r ve do\u011fru konumda ve izinlerde olmas\u0131 gerekir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong>.ssh Dizini:<\/strong> \u00d6zel anahtar\u0131n, kullan\u0131c\u0131n\u0131n ana dizinindeki <code>.ssh<\/code> dizininde bulundu\u011fundan emin olun. E\u011fer <code>.ssh<\/code> dizini yoksa, olu\u015fturun:\n<pre><code class=\"lang-bash\">mkdir ~\/<span class=\"hljs-selector-class\">.ssh<\/span>\r\nchmod <span class=\"hljs-number\">700<\/span> ~\/.ssh\r\n<\/code><\/pre>\n<\/li>\n<li><strong>\u00d6zel Anahtar Dosyas\u0131:<\/strong> \u00d6zel anahtar dosyas\u0131n\u0131n <code>.ssh<\/code> dizininde bulundu\u011fundan ve do\u011fru adland\u0131r\u0131ld\u0131\u011f\u0131ndan emin olun (\u00f6rne\u011fin, <code>id_rsa<\/code>).<\/li>\n<li><strong>\u0130zinler:<\/strong> \u00d6zel anahtar dosyas\u0131n\u0131n izinlerinin do\u011fru ayarland\u0131\u011f\u0131ndan emin olun. \u0130zinler, sadece kullan\u0131c\u0131n\u0131n okuma ve yazma eri\u015fimine sahip olmas\u0131n\u0131 sa\u011flamal\u0131d\u0131r:\n<pre><code class=\"lang-bash\">chmod <span class=\"hljs-number\">600<\/span> ~<span class=\"hljs-regexp\">\/.ssh\/i<\/span>d_rsa\r\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>Genel Anahtar\u0131n (Public Key) Sunucuda Do\u011fru Konuma Eklendi\u011finden Emin Olma (authorized_keys dosyas\u0131):<\/strong>Genel anahtar, sunucuda <code>authorized_keys<\/code> dosyas\u0131na eklenir. Bu dosya, hangi \u00f6zel anahtarlara sahip kullan\u0131c\u0131lar\u0131n sunucuya eri\u015febilece\u011fini belirtir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong>authorized_keys Dosyas\u0131:<\/strong> Genel anahtar\u0131n, sunucudaki kullan\u0131c\u0131n\u0131n ana dizinindeki <code>.ssh<\/code> dizininde bulunan <code>authorized_keys<\/code> dosyas\u0131na eklendi\u011finden emin olun. E\u011fer <code>authorized_keys<\/code> dosyas\u0131 yoksa, olu\u015fturun:\n<pre><code class=\"lang-bash\">touch ~<span class=\"hljs-regexp\">\/.ssh\/<\/span>authorized_keys\r\nchmod <span class=\"hljs-number\">600<\/span> ~<span class=\"hljs-regexp\">\/.ssh\/<\/span>authorized_keys\r\n<\/code><\/pre>\n<\/li>\n<li><strong>Genel Anahtar \u0130\u00e7eri\u011fi:<\/strong> Genel anahtar\u0131n i\u00e7eri\u011finin do\u011fru oldu\u011fundan ve <code>authorized_keys<\/code> dosyas\u0131na do\u011fru bir \u015fekilde kopyaland\u0131\u011f\u0131ndan emin olun. Kopyalama s\u0131ras\u0131nda olu\u015fabilecek hatalar\u0131 \u00f6nlemek i\u00e7in, <code>ssh-copy-id<\/code> komutunu kullanabilirsiniz:\n<pre><code class=\"lang-bash\">ssh-<span class=\"hljs-keyword\">copy<\/span>-id <span class=\"hljs-symbol\">&lt;kullanici_adi&gt;<\/span>@<span class=\"hljs-symbol\">&lt;sunucu_adresi&gt;<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, genel anahtar\u0131n\u0131z\u0131 sunucudaki <code>authorized_keys<\/code> dosyas\u0131na otomatik olarak kopyalar.<\/li>\n<li><strong>\u00c7ift T\u0131rnak \u0130\u00e7inde Bo\u015fluk:<\/strong> Genel anahtar\u0131n i\u00e7eri\u011fi <code>authorized_keys<\/code> dosyas\u0131na eklenirken, \u00e7ift t\u0131rnak veya ba\u015fka bir karakter eklenmedi\u011finden emin olun. Her anahtar ayr\u0131 bir sat\u0131rda olmal\u0131d\u0131r.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Anahtar \u0130zinlerini (chmod 600, chmod 700) Kontrol Etme:<\/strong><code>.ssh<\/code> dizininin ve <code>authorized_keys<\/code> dosyas\u0131n\u0131n izinlerinin do\u011fru ayarlanmas\u0131, g\u00fcvenlik ve i\u015flevsellik a\u00e7\u0131s\u0131ndan \u00f6nemlidir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong>.ssh Dizini \u0130zinleri:<\/strong> <code>.ssh<\/code> dizininin izinlerinin <code>700<\/code> olarak ayarland\u0131\u011f\u0131ndan emin olun:\n<pre><code class=\"lang-bash\">chmod <span class=\"hljs-number\">700<\/span> ~\/.ssh\r\n<\/code><\/pre>\n<p>Bu, sadece kullan\u0131c\u0131n\u0131n dizine okuma, yazma ve \u00e7al\u0131\u015ft\u0131rma eri\u015fimine sahip olmas\u0131n\u0131 sa\u011flar.<\/li>\n<li><strong>authorized_keys Dosyas\u0131 \u0130zinleri:<\/strong> <code>authorized_keys<\/code> dosyas\u0131n\u0131n izinlerinin <code>600<\/code> olarak ayarland\u0131\u011f\u0131ndan emin olun:\n<pre><code class=\"lang-bash\">chmod <span class=\"hljs-number\">600<\/span> ~<span class=\"hljs-regexp\">\/.ssh\/<\/span>authorized_keys\r\n<\/code><\/pre>\n<p>Bu, sadece kullan\u0131c\u0131n\u0131n dosyaya okuma ve yazma eri\u015fimine sahip olmas\u0131n\u0131 sa\u011flar.<\/li>\n<\/ul>\n<\/li>\n<li><strong><code>ssh-agent<\/code> Kullanarak Anahtar\u0131 Y\u00f6netme:<\/strong><code>ssh-agent<\/code>, \u00f6zel anahtarlar\u0131n\u0131z\u0131 bellekte tutan ve her SSH ba\u011flant\u0131s\u0131 i\u00e7in \u015fifre girmek zorunda kalmaman\u0131z\u0131 sa\u011flayan bir ara\u00e7t\u0131r.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong><code>ssh-agent<\/code>&#8216;\u0131 Ba\u015flatma:<\/strong> <code>ssh-agent<\/code>&#8216;\u0131 ba\u015flatmak i\u00e7in a\u015fa\u011f\u0131daki komutu kullan\u0131n:\n<pre><code class=\"lang-bash\"><span class=\"hljs-built_in\">eval<\/span> $(ssh-agent <span class=\"hljs-_\">-s<\/span>)\r\n<\/code><\/pre>\n<\/li>\n<li><strong>Anahtar\u0131 Ekleme:<\/strong> \u00d6zel anahtar\u0131n\u0131z\u0131 <code>ssh-agent<\/code>&#8216;a eklemek i\u00e7in a\u015fa\u011f\u0131daki komutu kullan\u0131n:\n<pre><code class=\"lang-bash\">ssh-<span class=\"hljs-keyword\">add<\/span><span class=\"bash\"> ~\/.ssh\/id_rsa<\/span>\r\n<\/code><\/pre>\n<p>E\u011fer \u00f6zel anahtar\u0131n\u0131z \u015fifrelenmi\u015fse, \u015fifrenizi girmeniz istenecektir.<\/li>\n<li><strong><code>ssh-agent<\/code>&#8216;\u0131 Otomatik Ba\u015flatma:<\/strong> <code>ssh-agent<\/code>&#8216;\u0131n her oturumda otomatik olarak ba\u015flamas\u0131 i\u00e7in, <code>.bashrc<\/code> veya <code>.zshrc<\/code> gibi kabuk yap\u0131land\u0131rma dosyan\u0131za a\u015fa\u011f\u0131daki sat\u0131rlar\u0131 ekleyin:\n<pre><code class=\"lang-bash\"><span class=\"hljs-keyword\">if<\/span> [ -z <span class=\"hljs-string\">\"<span class=\"hljs-variable\">$SSH_AUTH_SOCK<\/span>\"<\/span> ]; <span class=\"hljs-keyword\">then<\/span>\r\n    <span class=\"hljs-built_in\">eval<\/span> $(ssh-agent <span class=\"hljs-_\">-s<\/span>)\r\n<span class=\"hljs-keyword\">fi<\/span>\r\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>\u00c7ok Fakt\u00f6rl\u00fc Kimlik Do\u011frulama (MFA) Sorunlar\u0131 ve \u00c7\u00f6z\u00fcmleri<\/strong><\/p>\n<p>\u00c7ok fakt\u00f6rl\u00fc kimlik do\u011frulama (MFA), parolaya ek olarak, kullan\u0131c\u0131n\u0131n kimli\u011fini do\u011frulamak i\u00e7in ba\u015fka bir fakt\u00f6r (\u00f6rne\u011fin, tek kullan\u0131ml\u0131k kod, biyometrik veri) kullan\u0131r. Bu, g\u00fcvenlik seviyesini \u00f6nemli \u00f6l\u00e7\u00fcde art\u0131r\u0131r. Ancak, MFA konfig\u00fcrasyonunda hatalar yap\u0131lmas\u0131 durumunda ba\u011flant\u0131 sorunlar\u0131na yol a\u00e7abilir. <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken, MFA sorunlar\u0131n\u0131 anlamak ve gidermek \u00f6nemlidir.<\/p>\n<ul>\n<li><strong>Yanl\u0131\u015f Tek Kullan\u0131ml\u0131k Kod (OTP):<\/strong>MFA&#8217;da en yayg\u0131n kullan\u0131lan fakt\u00f6rlerden biri, tek kullan\u0131ml\u0131k koddur (OTP). OTP, bir uygulama (\u00f6rne\u011fin, Google Authenticator, Authy) veya SMS arac\u0131l\u0131\u011f\u0131yla \u00fcretilir ve s\u0131n\u0131rl\u0131 bir s\u00fcre i\u00e7in ge\u00e7erlidir. Yanl\u0131\u015f OTP girilmesi durumunda ba\u011flant\u0131 sorunu ya\u015fan\u0131r.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong>Do\u011fru OTP:<\/strong> OTP&#8217;nin do\u011fru girildi\u011finden emin olun. Yaz\u0131m hatalar\u0131n\u0131 kontrol edin.<\/li>\n<li><strong>Zaman Senkronizasyonu:<\/strong> OTP&#8217;nin \u00fcretildi\u011fi cihaz\u0131n (\u00f6rne\u011fin, telefon) saatinin do\u011fru ayarland\u0131\u011f\u0131ndan emin olun. Zaman senkronizasyonu sorunlar\u0131, yanl\u0131\u015f OTP \u00fcretimine yol a\u00e7abilir.<\/li>\n<li><strong>OTP Uygulamas\u0131:<\/strong> OTP uygulamas\u0131n\u0131n g\u00fcncel oldu\u011fundan emin olun.<\/li>\n<li><strong>Yedek Kodlar:<\/strong> MFA kurulumu s\u0131ras\u0131nda \u00fcretilen yedek kodlar\u0131 kullanmay\u0131 deneyin. Yedek kodlar, OTP&#8217;ye eri\u015fiminiz olmad\u0131\u011f\u0131nda kullan\u0131labilir.<\/li>\n<\/ul>\n<\/li>\n<li><strong>MFA Yap\u0131land\u0131rma Sorunlar\u0131:<\/strong>MFA&#8217;n\u0131n do\u011fru yap\u0131land\u0131r\u0131lmamas\u0131 durumunda, ba\u011flant\u0131 sorunlar\u0131 ya\u015fanabilir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong>PAM (Pluggable Authentication Modules) Yap\u0131land\u0131rmas\u0131:<\/strong> MFA&#8217;n\u0131n PAM arac\u0131l\u0131\u011f\u0131yla do\u011fru yap\u0131land\u0131r\u0131ld\u0131\u011f\u0131ndan emin olun. PAM, kimlik do\u011frulama y\u00f6ntemlerini y\u00f6netmek i\u00e7in kullan\u0131lan bir sistemdir. PAM yap\u0131land\u0131rma dosyalar\u0131 genellikle <code>\/etc\/pam.d\/<\/code> dizininde bulunur.<\/li>\n<li><strong><code>sshd_config<\/code> Dosyas\u0131:<\/strong> SSH sunucu yap\u0131land\u0131rma dosyas\u0131nda (<code>sshd_config<\/code>), MFA&#8217;n\u0131n etkinle\u015ftirildi\u011finden ve do\u011fru yap\u0131land\u0131r\u0131ld\u0131\u011f\u0131ndan emin olun.<\/li>\n<li><strong>MFA Sa\u011flay\u0131c\u0131s\u0131:<\/strong> Kulland\u0131\u011f\u0131n\u0131z MFA sa\u011flay\u0131c\u0131s\u0131n\u0131n (\u00f6rne\u011fin, Google Authenticator, Authy) dok\u00fcmantasyonunu inceleyin ve do\u011fru yap\u0131land\u0131rma ad\u0131mlar\u0131n\u0131 izleyin.<\/li>\n<\/ul>\n<\/li>\n<li><strong>MFA&#8217;y\u0131 Devre D\u0131\u015f\u0131 B\u0131rakma (Son \u00c7are):<\/strong>E\u011fer MFA ile ilgili sorunlar\u0131 \u00e7\u00f6zemiyorsan\u0131z ve sunucuya eri\u015fiminiz yoksa, MFA&#8217;y\u0131 devre d\u0131\u015f\u0131 b\u0131rakmak zorunda kalabilirsiniz. Bu, g\u00fcvenlik seviyesini d\u00fc\u015f\u00fcrece\u011fi i\u00e7in son \u00e7are olarak d\u00fc\u015f\u00fcn\u00fclmelidir.\n<p><strong>\u00c7\u00f6z\u00fcm:<\/strong><\/p>\n<ul>\n<li><strong>Sunucuya Eri\u015fim:<\/strong> Sunucuya ba\u015fka bir kullan\u0131c\u0131 ile veya kurtarma modunda eri\u015fim sa\u011flay\u0131n.<\/li>\n<li><strong>PAM Yap\u0131land\u0131rmas\u0131:<\/strong> PAM yap\u0131land\u0131rma dosyalar\u0131ndan MFA ile ilgili sat\u0131rlar\u0131 kald\u0131r\u0131n veya yorum sat\u0131r\u0131na al\u0131n.<\/li>\n<li><strong><code>sshd_config<\/code> Dosyas\u0131:<\/strong> SSH sunucu yap\u0131land\u0131rma dosyas\u0131nda MFA ile ilgili sat\u0131rlar\u0131 kald\u0131r\u0131n veya yorum sat\u0131r\u0131na al\u0131n.<\/li>\n<li><strong>SSH Servisini Yeniden Ba\u015flatma:<\/strong> SSH servisini yeniden ba\u015flat\u0131n.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryolar:<\/strong><\/p>\n<ul>\n<li><strong>Senaryo 1:<\/strong> Bir kullan\u0131c\u0131, sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak &#8220;Permission denied (publickey,password)&#8221; hatas\u0131 al\u0131r. Kullan\u0131c\u0131 ad\u0131n\u0131n ve \u015fifrenin do\u011fru oldu\u011fundan emindir. Ancak, <code>ssh-agent<\/code>&#8216;\u0131 ba\u015flatmad\u0131\u011f\u0131 i\u00e7in \u00f6zel anahtar\u0131n\u0131 belle\u011fe y\u00fcklememi\u015ftir. <code>eval $(ssh-agent -s)<\/code> ve <code>ssh-add ~\/.ssh\/id_rsa<\/code> komutlar\u0131n\u0131 kullanarak \u00f6zel anahtar\u0131n\u0131 belle\u011fe y\u00fckler ve ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/li>\n<li><strong>Senaryo 2:<\/strong> Bir sistem y\u00f6neticisi, bir sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak &#8220;Authentication failed&#8221; hatas\u0131 al\u0131r. SSH sunucusunda parola tabanl\u0131 kimlik do\u011frulaman\u0131n devre d\u0131\u015f\u0131 b\u0131rak\u0131ld\u0131\u011f\u0131n\u0131 ve sadece SSH anahtar\u0131 tabanl\u0131 kimlik do\u011frulaman\u0131n etkin oldu\u011funu fark eder. Ancak, genel anahtar\u0131 sunucudaki <code>authorized_keys<\/code> dosyas\u0131na do\u011fru bir \u015fekilde kopyalamam\u0131\u015ft\u0131r. <code>ssh-copy-id &lt;kullanici_adi&gt;@&lt;sunucu_adresi&gt;<\/code> komutunu kullanarak genel anahtar\u0131n\u0131 sunucudaki <code>authorized_keys<\/code> dosyas\u0131na kopyalar ve ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/li>\n<li><strong>Senaryo 3:<\/strong> Bir geli\u015ftirici, bir sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak &#8220;Invalid authentication response&#8221; hatas\u0131 al\u0131r. MFA&#8217;n\u0131n etkin oldu\u011funu ve OTP&#8217;nin yanl\u0131\u015f oldu\u011funu fark eder. Telefonunun saatinin yanl\u0131\u015f ayarland\u0131\u011f\u0131n\u0131 fark eder ve saati d\u00fczeltir. Ard\u0131ndan, do\u011fru OTP&#8217;yi girerek ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/li>\n<\/ul>\n<p>Bu b\u00f6l\u00fcm, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap arayan kullan\u0131c\u0131lara kimlik do\u011frulama sorunlar\u0131n\u0131 anlamalar\u0131 ve gidermeleri i\u00e7in kapsaml\u0131 bir rehber sunmaktad\u0131r. Parola tabanl\u0131 kimlik do\u011frulama, SSH anahtar\u0131 tabanl\u0131 kimlik do\u011frulama ve \u00e7ok fakt\u00f6rl\u00fc kimlik do\u011frulama y\u00f6ntemlerini, olas\u0131 sorunlar\u0131 ve ad\u0131m ad\u0131m \u00e7\u00f6z\u00fcm \u00f6nerilerini detayl\u0131 bir \u015fekilde inceledik. Kimlik do\u011frulama sorunlar\u0131n\u0131 \u00e7\u00f6zmek, SSH ba\u011flant\u0131 sorunlar\u0131n\u0131n b\u00fcy\u00fck bir b\u00f6l\u00fcm\u00fcn\u00fc \u00e7\u00f6zmenize yard\u0131mc\u0131 olacakt\u0131r.<\/p>\n<h2 id=\"4-g-venlik-duvar-firewall-ve-a-yap-land-rmas-sorunlar-\"><span class=\"ez-toc-section\" id=\"4_Guvenlik_Duvari_Firewall_ve_Ag_Yapilandirmasi_Sorunlari\"><\/span>4. G\u00fcvenlik Duvar\u0131 (Firewall) ve A\u011f Yap\u0131land\u0131rmas\u0131 Sorunlar\u0131<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>G\u00fcvenlik duvarlar\u0131 (firewall) ve a\u011f yap\u0131land\u0131rmas\u0131, SSH ba\u011flant\u0131 problemlerinin \u00f6nemli bir b\u00f6l\u00fcm\u00fcn\u00fc olu\u015fturur. Bir g\u00fcvenlik duvar\u0131, a\u011f trafi\u011fini filtreleyerek yetkisiz eri\u015fimi engeller ve sunucunuzu k\u00f6t\u00fc ama\u00e7l\u0131 sald\u0131r\u0131lardan korur. Ancak, yanl\u0131\u015f yap\u0131land\u0131r\u0131lm\u0131\u015f bir g\u00fcvenlik duvar\u0131, SSH ba\u011flant\u0131lar\u0131n\u0131 engelleyebilir ve eri\u015fim sorunlar\u0131na yol a\u00e7abilir. Benzer \u015fekilde, hatal\u0131 a\u011f yap\u0131land\u0131rmas\u0131 da SSH ba\u011flant\u0131lar\u0131n\u0131 kesintiye u\u011fratabilir. Bu b\u00f6l\u00fcmde, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna odaklanarak g\u00fcvenlik duvar\u0131 ve a\u011f yap\u0131land\u0131rmas\u0131 ile ilgili sorunlar\u0131 ve \u00e7\u00f6z\u00fcm yollar\u0131n\u0131 detayl\u0131 bir \u015fekilde inceleyece\u011fiz.<\/p>\n<p><strong>G\u00fcvenlik Duvar\u0131 Kavram\u0131 ve \u00d6nemi<\/strong><\/p>\n<p>G\u00fcvenlik duvar\u0131, bir a\u011f veya sistem ile d\u0131\u015f d\u00fcnya aras\u0131ndaki trafi\u011fi kontrol eden bir g\u00fcvenlik sistemidir. Temel amac\u0131, yetkisiz eri\u015fimi engellemek ve k\u00f6t\u00fc ama\u00e7l\u0131 yaz\u0131l\u0131mlar\u0131n sisteme bula\u015fmas\u0131n\u0131 \u00f6nlemektir. G\u00fcvenlik duvarlar\u0131, \u00f6nceden tan\u0131mlanm\u0131\u015f kurallara g\u00f6re trafi\u011fi filtreler ve belirli portlar \u00fczerinden gelen veya giden ba\u011flant\u0131lar\u0131 engelleyebilir veya izin verebilir.<\/p>\n<p><strong>G\u00fcvenlik Duvar\u0131 T\u00fcrleri:<\/strong><\/p>\n<ul>\n<li><strong>Donan\u0131m G\u00fcvenlik Duvarlar\u0131:<\/strong> Genellikle bir a\u011f\u0131n giri\u015f noktas\u0131nda bulunan fiziksel cihazlard\u0131r. Daha karma\u015f\u0131k ve g\u00fc\u00e7l\u00fc g\u00fcvenlik \u00f6zellikleri sunarlar.<\/li>\n<li><strong>Yaz\u0131l\u0131m G\u00fcvenlik Duvarlar\u0131:<\/strong> \u0130\u015fletim sistemleri \u00fczerinde \u00e7al\u0131\u015fan yaz\u0131l\u0131m uygulamalar\u0131d\u0131r. Daha basit ve kullan\u0131m\u0131 kolayd\u0131rlar.<\/li>\n<\/ul>\n<p><strong>Yayg\u0131n G\u00fcvenlik Duvar\u0131 Yaz\u0131l\u0131mlar\u0131:<\/strong><\/p>\n<ul>\n<li><strong>iptables (Linux):<\/strong> Linux sistemlerde kullan\u0131lan, komut sat\u0131r\u0131 tabanl\u0131 bir g\u00fcvenlik duvar\u0131 arac\u0131d\u0131r. \u00c7ok esnektir ve geni\u015f bir yelpazede kural tan\u0131mlama olana\u011f\u0131 sunar.<\/li>\n<li><strong>UFW (Uncomplicated Firewall &#8211; Linux):<\/strong> iptables&#8217;\u0131n daha kullan\u0131c\u0131 dostu bir aray\u00fcz\u00fcd\u00fcr. Ubuntu ve Debian gibi da\u011f\u0131t\u0131mlarda yayg\u0131n olarak kullan\u0131l\u0131r.<\/li>\n<li><strong>firewalld (Linux):<\/strong> CentOS, Fedora ve RHEL gibi da\u011f\u0131t\u0131mlarda kullan\u0131lan, dinamik bir g\u00fcvenlik duvar\u0131 y\u00f6netim arac\u0131d\u0131r.<\/li>\n<li><strong>Windows Defender Firewall (Windows):<\/strong> Windows i\u015fletim sistemlerinde yerle\u015fik olarak bulunan bir g\u00fcvenlik duvar\u0131d\u0131r.<\/li>\n<li><strong>pf (Packet Filter &#8211; BSD):<\/strong> FreeBSD, OpenBSD ve NetBSD gibi BSD tabanl\u0131 sistemlerde kullan\u0131lan bir g\u00fcvenlik duvar\u0131d\u0131r.<\/li>\n<\/ul>\n<p><strong>G\u00fcvenlik Duvar\u0131 Ayarlar\u0131n\u0131 Kontrol Etme<\/strong><\/p>\n<p><strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken, ilk ad\u0131m g\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131 kontrol etmektir. SSH trafi\u011finin engellenip engellenmedi\u011fini belirlemek i\u00e7in g\u00fcvenlik duvar\u0131 yap\u0131land\u0131rman\u0131z\u0131 incelemeniz gerekir.<\/p>\n<p><strong>1. UFW (Uncomplicated Firewall) ile G\u00fcvenlik Duvar\u0131 Ayarlar\u0131n\u0131 Kontrol Etme (Linux)<\/strong><\/p>\n<p>UFW, Ubuntu ve Debian gibi sistemlerde yayg\u0131n olarak kullan\u0131lan, kullan\u0131c\u0131 dostu bir g\u00fcvenlik duvar\u0131 arac\u0131d\u0131r.<\/p>\n<ul>\n<li><strong>UFW Durumunu Kontrol Etme:<\/strong>UFW&#8217;nin aktif olup olmad\u0131\u011f\u0131n\u0131 ve mevcut kurallar\u0131 g\u00f6rmek i\u00e7in a\u015fa\u011f\u0131daki komutu kullan\u0131n:\n<pre><code class=\"lang-bash\">sudo ufw <span class=\"hljs-built_in\">status<\/span> <span class=\"hljs-built_in\">verbose<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, UFW&#8217;nin durumunu, varsay\u0131lan politikalar\u0131n\u0131 ve etkin kurallar\u0131n\u0131 g\u00f6sterir.<\/p>\n<p><strong>\u00d6rnek \u00c7\u0131kt\u0131:<\/strong><\/p>\n<pre><code>Status: active\r\nLogging: <span class=\"hljs-keyword\">on<\/span> (low)\r\n<span class=\"hljs-keyword\">Default<\/span>: deny (incoming), allow (outgoing), disabled (routed)\r\n<span class=\"hljs-keyword\">New<\/span> profiles: <span class=\"hljs-keyword\">skip<\/span>\r\n\r\n<span class=\"hljs-keyword\">To<\/span>                         Action      <span class=\"hljs-keyword\">From<\/span>\r\n--                         ------      ----\r\n<span class=\"hljs-number\">22<\/span>\/tcp                     ALLOW <span class=\"hljs-keyword\">IN<\/span>    Anywhere\r\n<span class=\"hljs-number\">22<\/span>                         ALLOW <span class=\"hljs-keyword\">IN<\/span>    Anywhere\r\n<span class=\"hljs-number\">80<\/span>\/tcp                     ALLOW <span class=\"hljs-keyword\">IN<\/span>    Anywhere\r\n<span class=\"hljs-number\">443<\/span>\/tcp                    ALLOW <span class=\"hljs-keyword\">IN<\/span>    Anywhere\r\n<span class=\"hljs-number\">22<\/span>\/tcp (v6)                ALLOW <span class=\"hljs-keyword\">IN<\/span>    Anywhere (v6)\r\n<span class=\"hljs-number\">22<\/span> (v6)                    ALLOW <span class=\"hljs-keyword\">IN<\/span>    Anywhere (v6)\r\n<span class=\"hljs-number\">80<\/span>\/tcp (v6)                ALLOW <span class=\"hljs-keyword\">IN<\/span>    Anywhere (v6)\r\n<span class=\"hljs-number\">443<\/span>\/tcp (v6)               ALLOW <span class=\"hljs-keyword\">IN<\/span>    Anywhere (v6)\r\n<\/code><\/pre>\n<p>Bu \u00e7\u0131kt\u0131, UFW&#8217;nin aktif oldu\u011funu, gelen ba\u011flant\u0131lar\u0131n varsay\u0131lan olarak engellendi\u011fini (deny incoming) ve 22 (SSH), 80 (HTTP) ve 443 (HTTPS) portlar\u0131na izin verildi\u011fini g\u00f6sterir.<\/li>\n<li><strong>SSH Trafi\u011fine \u0130zin Verme:<\/strong>E\u011fer UFW&#8217;de SSH trafi\u011fine izin verilmiyorsa, a\u015fa\u011f\u0131daki komutlar\u0131 kullanarak izin verebilirsiniz:\n<ul>\n<li><strong>Port 22&#8217;ye \u0130zin Verme (TCP):<\/strong>\n<pre><code class=\"lang-bash\">sudo ufw allow <span class=\"hljs-number\">22<\/span>\/tcp\r\n<\/code><\/pre>\n<\/li>\n<li><strong>SSH Servisine \u0130zin Verme (UFW Profilini Kullanarak):<\/strong>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo ufw allow ssh<\/span>\r\n<\/code><\/pre>\n<\/li>\n<li><strong>Belirli Bir IP Adresinden Gelen SSH Trafi\u011fine \u0130zin Verme:<\/strong>\n<pre><code class=\"lang-bash\">sudo ufw allow <span class=\"hljs-keyword\">from<\/span> <span class=\"hljs-variable\">&lt;IP_adresi&gt;<\/span> <span class=\"hljs-keyword\">to<\/span> <span class=\"hljs-literal\">any<\/span> <span class=\"hljs-keyword\">port<\/span> <span class=\"hljs-number\">22<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;IP_adresi&gt;<\/code> yerine, izin vermek istedi\u011finiz IP adresini yaz\u0131n (\u00f6rne\u011fin, 192.168.1.100).<\/li>\n<li><strong>Belirli Bir A\u011fdan Gelen SSH Trafi\u011fine \u0130zin Verme:<\/strong>\n<pre><code class=\"lang-bash\">sudo ufw allow <span class=\"hljs-keyword\">from<\/span> <span class=\"hljs-variable\">&lt;a\u011f_adresi&gt;<\/span>\/<span class=\"hljs-variable\">&lt;alt_a\u011f_maskesi&gt;<\/span> <span class=\"hljs-keyword\">to<\/span> <span class=\"hljs-literal\">any<\/span> <span class=\"hljs-keyword\">port<\/span> <span class=\"hljs-number\">22<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;a\u011f_adresi&gt;\/&lt;alt_a\u011f_maskesi&gt;<\/code> yerine, izin vermek istedi\u011finiz a\u011f adresini ve alt a\u011f maskesini yaz\u0131n (\u00f6rne\u011fin, 192.168.1.0\/24).<\/li>\n<\/ul>\n<\/li>\n<li><strong>UFW&#8217;yi Etkinle\u015ftirme ve Yeniden Y\u00fckleme:<\/strong>Kurallar\u0131 ekledikten veya de\u011fi\u015ftirdikten sonra, UFW&#8217;yi etkinle\u015ftirmeniz veya yeniden y\u00fcklemeniz gerekir:\n<pre><code class=\"lang-bash\">sudo ufw <span class=\"hljs-built_in\">enable<\/span>\r\n<\/code><\/pre>\n<p>veya<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo ufw reload<\/span>\r\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<p><strong>2. iptables ile G\u00fcvenlik Duvar\u0131 Ayarlar\u0131n\u0131 Kontrol Etme (Linux)<\/strong><\/p>\n<p>iptables, Linux sistemlerde kullan\u0131lan, komut sat\u0131r\u0131 tabanl\u0131 bir g\u00fcvenlik duvar\u0131 arac\u0131d\u0131r. Daha karma\u015f\u0131k ve esnektir, ancak UFW&#8217;ye g\u00f6re kullan\u0131m\u0131 daha zordur.<\/p>\n<ul>\n<li><strong>iptables Kurallar\u0131n\u0131 G\u00f6r\u00fcnt\u00fcleme:<\/strong>iptables kurallar\u0131n\u0131 g\u00f6r\u00fcnt\u00fclemek i\u00e7in a\u015fa\u011f\u0131daki komutu kullan\u0131n:\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo iptables -L<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, iptables&#8217;\u0131n farkl\u0131 zincirlerindeki (INPUT, OUTPUT, FORWARD) kurallar\u0131n bir listesini g\u00f6r\u00fcnt\u00fcler.<\/p>\n<p><strong>\u00d6rnek \u00c7\u0131kt\u0131:<\/strong><\/p>\n<pre><code>Chain INPUT (policy ACCEPT)\r\ntarget     prot <span class=\"hljs-keyword\">opt<\/span> <span class=\"hljs-keyword\">source<\/span>               destination\r\nACCEPT     tcp  --  anywhere             anywhere             tcp <span class=\"hljs-keyword\">dp<\/span><span class=\"hljs-variable\">t:ssh<\/span>\r\nACCEPT     tcp  --  anywhere             anywhere             tcp <span class=\"hljs-keyword\">dp<\/span><span class=\"hljs-variable\">t:http<\/span>\r\nACCEPT     tcp  --  anywhere             anywhere             tcp <span class=\"hljs-keyword\">dp<\/span><span class=\"hljs-variable\">t:https<\/span>\r\n\r\nChain FORWARD (policy ACCEPT)\r\ntarget     prot <span class=\"hljs-keyword\">opt<\/span> <span class=\"hljs-keyword\">source<\/span>               destination\r\n\r\nChain OUTPUT (policy ACCEPT)\r\ntarget     prot <span class=\"hljs-keyword\">opt<\/span> <span class=\"hljs-keyword\">source<\/span>               destination\r\n<\/code><\/pre>\n<p>Bu \u00e7\u0131kt\u0131, INPUT zincirinde SSH (tcp dpt:ssh), HTTP (tcp dpt:http) ve HTTPS (tcp dpt:https) trafi\u011fine izin verildi\u011fini g\u00f6sterir.<\/li>\n<li><strong>SSH Trafi\u011fine \u0130zin Verme:<\/strong>E\u011fer iptables&#8217;da SSH trafi\u011fine izin verilmiyorsa, a\u015fa\u011f\u0131daki komutlar\u0131 kullanarak izin verebilirsiniz:\n<ul>\n<li><strong>Port 22&#8217;ye \u0130zin Verme (TCP):<\/strong>\n<pre><code class=\"lang-bash\">sudo iptables -A INPUT -<span class=\"hljs-selector-tag\">p<\/span> tcp --dport <span class=\"hljs-number\">22<\/span> -j ACCEPT\r\n<\/code><\/pre>\n<\/li>\n<li><strong>Belirli Bir IP Adresinden Gelen SSH Trafi\u011fine \u0130zin Verme:<\/strong>\n<pre><code class=\"lang-bash\">sudo iptables -A INPUT -<span class=\"hljs-selector-tag\">p<\/span> tcp --dport <span class=\"hljs-number\">22<\/span> -s &lt;IP_adresi&gt; -j ACCEPT\r\n<\/code><\/pre>\n<p><code>&lt;IP_adresi&gt;<\/code> yerine, izin vermek istedi\u011finiz IP adresini yaz\u0131n (\u00f6rne\u011fin, 192.168.1.100).<\/li>\n<li><strong>Belirli Bir A\u011fdan Gelen SSH Trafi\u011fine \u0130zin Verme:<\/strong>\n<pre><code class=\"lang-bash\">sudo iptables -A INPUT -p tcp <span class=\"hljs-comment\">--dport 22 -s &lt;a\u011f_adresi&gt;\/&lt;alt_a\u011f_maskesi&gt; -j ACCEPT<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;a\u011f_adresi&gt;\/&lt;alt_a\u011f_maskesi&gt;<\/code> yerine, izin vermek istedi\u011finiz a\u011f adresini ve alt a\u011f maskesini yaz\u0131n (\u00f6rne\u011fin, 192.168.1.0\/24).<\/li>\n<\/ul>\n<\/li>\n<li><strong>iptables Kurallar\u0131n\u0131 Kaydetme:<\/strong>iptables kurallar\u0131, sistem yeniden ba\u015flat\u0131ld\u0131\u011f\u0131nda kaybolabilir. Kurallar\u0131n kal\u0131c\u0131 olmas\u0131 i\u00e7in, a\u015fa\u011f\u0131daki komutlar\u0131 kullanarak kaydedebilirsiniz:\n<ul>\n<li><strong>Debian\/Ubuntu:<\/strong>\n<pre><code class=\"lang-bash\">sudo apt-get install iptables-<span class=\"hljs-keyword\">persistent<\/span>\r\nsudo netfilter-<span class=\"hljs-keyword\">persistent<\/span> save\r\n<\/code><\/pre>\n<\/li>\n<li><strong>CentOS\/RHEL:<\/strong>\n<pre><code class=\"lang-bash\">sudo yum <span class=\"hljs-keyword\">install<\/span> iptables-services\r\nsudo service iptables <span class=\"hljs-keyword\">save<\/span>\r\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>3. firewalld ile G\u00fcvenlik Duvar\u0131 Ayarlar\u0131n\u0131 Kontrol Etme (Linux)<\/strong><\/p>\n<p>firewalld, CentOS, Fedora ve RHEL gibi da\u011f\u0131t\u0131mlarda kullan\u0131lan, dinamik bir g\u00fcvenlik duvar\u0131 y\u00f6netim arac\u0131d\u0131r. B\u00f6lgeler (zones) kavram\u0131n\u0131 kullanarak a\u011f aray\u00fczlerine farkl\u0131 g\u00fcvenlik seviyeleri ataman\u0131za olanak tan\u0131r.<\/p>\n<ul>\n<li><strong>firewalld Durumunu Kontrol Etme:<\/strong>firewalld&#8217;nin aktif olup olmad\u0131\u011f\u0131n\u0131 ve mevcut kurallar\u0131 g\u00f6rmek i\u00e7in a\u015fa\u011f\u0131daki komutu kullan\u0131n:\n<pre><code class=\"lang-bash\">sudo firewall-<span class=\"hljs-keyword\">cmd<\/span><span class=\"bash\"> --state\r\n<\/span>sudo firewall-<span class=\"hljs-keyword\">cmd<\/span><span class=\"bash\"> --list-all<\/span>\r\n<\/code><\/pre>\n<p><code>sudo firewall-cmd --state<\/code> komutu, firewalld&#8217;nin durumunu (running veya not running) g\u00f6sterir. <code>sudo firewall-cmd --list-all<\/code> komutu, varsay\u0131lan b\u00f6lgenin (genellikle public) ayarlar\u0131n\u0131, etkin servisleri ve portlar\u0131 g\u00f6sterir.<\/p>\n<p><strong>\u00d6rnek \u00c7\u0131kt\u0131:<\/strong><\/p>\n<pre><code>firewalld <span class=\"hljs-keyword\">is<\/span> running\r\npublic (active)\r\n  targe<span class=\"hljs-variable\">t:<\/span> default\r\n  icmp-block-inversion: <span class=\"hljs-keyword\">no<\/span>\r\n  interface<span class=\"hljs-variable\">s:<\/span> eth0\r\n  <span class=\"hljs-keyword\">source<\/span><span class=\"hljs-variable\">s:<\/span>\r\n  service<span class=\"hljs-variable\">s:<\/span> dhcpv6-client http https ssh\r\n  port<span class=\"hljs-variable\">s:<\/span>\r\n  protocol<span class=\"hljs-variable\">s:<\/span>\r\n  masquerade: <span class=\"hljs-keyword\">no<\/span>\r\n  forward-port<span class=\"hljs-variable\">s:<\/span>\r\n  <span class=\"hljs-keyword\">source<\/span>-port<span class=\"hljs-variable\">s:<\/span>\r\n  icmp-block<span class=\"hljs-variable\">s:<\/span>\r\n  rich rule<span class=\"hljs-variable\">s:<\/span>\r\n<\/code><\/pre>\n<p>Bu \u00e7\u0131kt\u0131, firewalld&#8217;nin \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131, public b\u00f6lgesinin etkin oldu\u011funu ve eth0 aray\u00fcz\u00fcne atand\u0131\u011f\u0131n\u0131, SSH servisine izin verildi\u011fini g\u00f6sterir.<\/li>\n<li><strong>SSH Servisine \u0130zin Verme:<\/strong>E\u011fer firewalld&#8217;de SSH servisine izin verilmiyorsa, a\u015fa\u011f\u0131daki komutlar\u0131 kullanarak izin verebilirsiniz:\n<ul>\n<li><strong>SSH Servisine \u0130zin Verme (Kal\u0131c\u0131):<\/strong>\n<pre><code class=\"lang-bash\"><span class=\"hljs-comment\">sudo<\/span> <span class=\"hljs-comment\">firewall<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-comment\">cmd<\/span> <span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-comment\">permanent<\/span> <span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-comment\">add<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-comment\">service=ssh<\/span>\r\n<\/code><\/pre>\n<\/li>\n<li><strong>Port 22&#8217;ye \u0130zin Verme (TCP, Kal\u0131c\u0131):<\/strong>\n<pre><code class=\"lang-bash\"><span class=\"hljs-comment\">sudo<\/span> <span class=\"hljs-comment\">firewall<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-comment\">cmd<\/span> <span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-comment\">permanent<\/span> <span class=\"hljs-literal\">-<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-comment\">add<\/span><span class=\"hljs-literal\">-<\/span><span class=\"hljs-comment\">port=22\/tcp<\/span>\r\n<\/code><\/pre>\n<\/li>\n<li><strong>Belirli Bir IP Adresinden Gelen SSH Trafi\u011fine \u0130zin Verme (Kal\u0131c\u0131):<\/strong>\n<pre><code class=\"lang-bash\">sudo firewall-cmd --permanent --add-rich-rule='<span class=\"hljs-keyword\">rule<\/span> family=<span class=\"hljs-string\">\"ipv4\"<\/span> source address=<span class=\"hljs-string\">\"&lt;IP_adresi&gt;\"<\/span> <span class=\"hljs-keyword\">port<\/span> <span class=\"hljs-keyword\">port<\/span>=<span class=\"hljs-string\">\"22\"<\/span> protocol=<span class=\"hljs-string\">\"tcp\"<\/span> accept'\r\n<\/code><\/pre>\n<p><code>&lt;IP_adresi&gt;<\/code> yerine, izin vermek istedi\u011finiz IP adresini yaz\u0131n (\u00f6rne\u011fin, 192.168.1.100).<\/li>\n<li><strong>Belirli Bir A\u011fdan Gelen SSH Trafi\u011fine \u0130zin Verme (Kal\u0131c\u0131):<\/strong>\n<pre><code class=\"lang-bash\">sudo firewall-cmd --permanent --add-rich-rule='<span class=\"hljs-keyword\">rule<\/span> family=<span class=\"hljs-string\">\"ipv4\"<\/span> source address=<span class=\"hljs-string\">\"&lt;a\u011f_adresi&gt;\/&lt;alt_a\u011f_maskesi&gt;\"<\/span> <span class=\"hljs-keyword\">port<\/span> <span class=\"hljs-keyword\">port<\/span>=<span class=\"hljs-string\">\"22\"<\/span> protocol=<span class=\"hljs-string\">\"tcp\"<\/span> accept'\r\n<\/code><\/pre>\n<p><code>&lt;a\u011f_adresi&gt;\/&lt;alt_a\u011f_maskesi&gt;<\/code> yerine, izin vermek istedi\u011finiz a\u011f adresini ve alt a\u011f maskesini yaz\u0131n (\u00f6rne\u011fin, 192.168.1.0\/24).<\/li>\n<\/ul>\n<\/li>\n<li><strong>firewalld&#8217;yi Yeniden Y\u00fckleme:<\/strong>Kurallar\u0131 ekledikten veya de\u011fi\u015ftirdikten sonra, firewalld&#8217;yi yeniden y\u00fcklemeniz gerekir:\n<pre><code class=\"lang-bash\">sudo firewall-<span class=\"hljs-keyword\">cmd<\/span><span class=\"bash\"> --reload<\/span>\r\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<p><strong>4. Windows Defender Firewall ile G\u00fcvenlik Duvar\u0131 Ayarlar\u0131n\u0131 Kontrol Etme (Windows)<\/strong><\/p>\n<p>Windows Defender Firewall, Windows i\u015fletim sistemlerinde yerle\u015fik olarak bulunan bir g\u00fcvenlik duvar\u0131d\u0131r.<\/p>\n<ul>\n<li><strong>Windows Defender Firewall&#8217;u A\u00e7ma:<\/strong>Denetim Masas\u0131 &gt; Sistem ve G\u00fcvenlik &gt; Windows Defender G\u00fcvenlik Duvar\u0131&#8217;na gidin.<\/li>\n<li><strong>Gelen Kurallar\u0131 G\u00f6r\u00fcnt\u00fcleme:<\/strong>Sol taraftaki men\u00fcden &#8220;Geli\u015fmi\u015f ayarlar&#8221;\u0131 t\u0131klay\u0131n. &#8220;Gelen Kurallar\u0131&#8221; b\u00f6l\u00fcm\u00fcne gidin.<\/li>\n<li><strong>SSH Trafi\u011fine \u0130zin Verme:<\/strong>E\u011fer SSH trafi\u011fine izin veren bir kural yoksa, yeni bir kural olu\u015fturun:\n<ol>\n<li>Sa\u011f taraftaki men\u00fcden &#8220;Yeni Kural&#8230;&#8221;&#8216;i t\u0131klay\u0131n.<\/li>\n<li>&#8220;Port&#8221; se\u00e7ene\u011fini se\u00e7in ve &#8220;\u0130leri&#8221;yi t\u0131klay\u0131n.<\/li>\n<li>&#8220;Belirli yerel portlar&#8221; se\u00e7ene\u011fini se\u00e7in ve &#8220;22&#8221; yaz\u0131n. &#8220;\u0130leri&#8221;yi t\u0131klay\u0131n.<\/li>\n<li>&#8220;Ba\u011flant\u0131ya izin ver&#8221; se\u00e7ene\u011fini se\u00e7in ve &#8220;\u0130leri&#8221;yi t\u0131klay\u0131n.<\/li>\n<li>Hangi profiller i\u00e7in (Etki Alan\u0131, \u00d6zel, Genel) kural\u0131n ge\u00e7erli olaca\u011f\u0131n\u0131 se\u00e7in ve &#8220;\u0130leri&#8221;yi t\u0131klay\u0131n.<\/li>\n<li>Kurala bir ad verin (\u00f6rne\u011fin, &#8220;SSH \u0130zin Ver&#8221;) ve &#8220;Son&#8221;u t\u0131klay\u0131n.<\/li>\n<\/ol>\n<\/li>\n<\/ul>\n<p><strong>Bulut Platformlar\u0131ndaki (AWS, Azure, GCP) G\u00fcvenlik Gruplar\u0131n\u0131 Kontrol Etme<\/strong><\/p>\n<p>Bulut platformlar\u0131 (AWS, Azure, GCP), sanal makineleri (VM) ve di\u011fer bulut kaynaklar\u0131n\u0131 korumak i\u00e7in g\u00fcvenlik gruplar\u0131 (security groups) veya a\u011f g\u00fcvenlik gruplar\u0131 (network security groups) gibi sanal g\u00fcvenlik duvarlar\u0131 sunar. <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken, bulut platformlar\u0131ndaki g\u00fcvenlik gruplar\u0131n\u0131n do\u011fru yap\u0131land\u0131r\u0131ld\u0131\u011f\u0131ndan emin olmak \u00f6nemlidir.<\/p>\n<ul>\n<li><strong>AWS G\u00fcvenlik Gruplar\u0131:<\/strong>AWS&#8217;de, g\u00fcvenlik gruplar\u0131 EC2 \u00f6rneklerini korumak i\u00e7in kullan\u0131l\u0131r. Her g\u00fcvenlik grubu, gelen ve giden trafi\u011fe izin veren veya engelleyen bir dizi kural i\u00e7erir.\n<ul>\n<li><strong>G\u00fcvenlik Grubunu Kontrol Etme:<\/strong> AWS Management Console&#8217;da EC2 &gt; G\u00fcvenlik Gruplar\u0131&#8217;na gidin. \u0130lgili g\u00fcvenlik grubunu se\u00e7in ve &#8220;Gelen Kurallar&#8221; ve &#8220;Giden Kurallar&#8221; sekmelerini inceleyin.<\/li>\n<li><strong>SSH Trafi\u011fine \u0130zin Verme:<\/strong> Gelen kurallarda, 22 numaral\u0131 port \u00fczerinden TCP trafi\u011fine izin veren bir kural\u0131n oldu\u011fundan emin olun. E\u011fer yoksa, yeni bir kural ekleyin:\n<ul>\n<li>&#8220;Gelen Kurallar\u0131&#8221; sekmesinde &#8220;Kural Ekle&#8221;yi t\u0131klay\u0131n.<\/li>\n<li>&#8220;T\u00fcr&#8221; olarak &#8220;SSH&#8221; se\u00e7in.<\/li>\n<li>&#8220;Kaynak&#8221; olarak &#8220;\u00d6zel&#8221; veya &#8220;Her Yerden (0.0.0.0\/0)&#8221; se\u00e7in (g\u00fcvenlik gereksinimlerinize ba\u011fl\u0131 olarak).<\/li>\n<li>&#8220;Kaydet&#8221;i t\u0131klay\u0131n.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>Azure A\u011f G\u00fcvenlik Gruplar\u0131:<\/strong>Azure&#8217;da, a\u011f g\u00fcvenlik gruplar\u0131 (NSG), sanal a\u011flar\u0131 ve alt a\u011flar\u0131 korumak i\u00e7in kullan\u0131l\u0131r. NSG&#8217;ler, gelen ve giden trafi\u011fe izin veren veya engelleyen bir dizi kural i\u00e7erir.\n<ul>\n<li><strong>A\u011f G\u00fcvenlik Grubunu Kontrol Etme:<\/strong> Azure Portal&#8217;da Sanal Makineler &gt; A\u011f &gt; A\u011f G\u00fcvenlik Grubu&#8217;na gidin. \u0130lgili a\u011f g\u00fcvenlik grubunu se\u00e7in ve &#8220;Gelen g\u00fcvenlik kurallar\u0131&#8221; ve &#8220;Giden g\u00fcvenlik kurallar\u0131&#8221; sekmelerini inceleyin.<\/li>\n<li><strong>SSH Trafi\u011fine \u0130zin Verme:<\/strong> Gelen g\u00fcvenlik kurallar\u0131nda, 22 numaral\u0131 port \u00fczerinden TCP trafi\u011fine izin veren bir kural\u0131n oldu\u011fundan emin olun. E\u011fer yoksa, yeni bir kural ekleyin:\n<ul>\n<li>&#8220;Gelen g\u00fcvenlik kurallar\u0131&#8221; sekmesinde &#8220;Ekle&#8221;yi t\u0131klay\u0131n.<\/li>\n<li>&#8220;Kaynak&#8221; olarak &#8220;Herhangi biri&#8221; veya &#8220;IP adresleri&#8221; se\u00e7in (g\u00fcvenlik gereksinimlerinize ba\u011fl\u0131 olarak).<\/li>\n<li>&#8220;Kaynak port aral\u0131klar\u0131&#8221; olarak &#8220;*&#8221; yaz\u0131n.<\/li>\n<li>&#8220;Hedef&#8221; olarak &#8220;Herhangi biri&#8221; se\u00e7in.<\/li>\n<li>&#8220;Hedef port aral\u0131klar\u0131&#8221; olarak &#8220;22&#8221; yaz\u0131n.<\/li>\n<li>&#8220;Protokol&#8221; olarak &#8220;TCP&#8221; se\u00e7in.<\/li>\n<li>&#8220;Eylem&#8221; olarak &#8220;\u0130zin Ver&#8221; se\u00e7in.<\/li>\n<li>&#8220;\u00d6ncelik&#8221; i\u00e7in benzersiz bir de\u011fer girin.<\/li>\n<li>&#8220;Ad&#8221; i\u00e7in bir ad verin (\u00f6rne\u011fin, &#8220;SSH \u0130zin Ver&#8221;).<\/li>\n<li>&#8220;Ekle&#8221;yi t\u0131klay\u0131n.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>GCP G\u00fcvenlik Duvar\u0131 Kurallar\u0131:<\/strong>GCP&#8217;de, g\u00fcvenlik duvar\u0131 kurallar\u0131 sanal makineleri (VM) korumak i\u00e7in kullan\u0131l\u0131r. Her g\u00fcvenlik duvar\u0131 kural\u0131, gelen ve giden trafi\u011fe izin veren veya engelleyen bir dizi \u00f6zellik i\u00e7erir.\n<ul>\n<li><strong>G\u00fcvenlik Duvar\u0131 Kurallar\u0131n\u0131 Kontrol Etme:<\/strong> GCP Console&#8217;da VPC a\u011f\u0131 &gt; G\u00fcvenlik Duvar\u0131 kurallar\u0131&#8217;na gidin. \u0130lgili g\u00fcvenlik duvar\u0131 kural\u0131n\u0131 se\u00e7in ve \u00f6zelliklerini inceleyin.<\/li>\n<li><strong>SSH Trafi\u011fine \u0130zin Verme:<\/strong> Gelen trafik kurallar\u0131nda, 22 numaral\u0131 port \u00fczerinden TCP trafi\u011fine izin veren bir kural\u0131n oldu\u011fundan emin olun. E\u011fer yoksa, yeni bir kural ekleyin:\n<ul>\n<li>&#8220;G\u00fcvenlik duvar\u0131 kural\u0131 olu\u015ftur&#8221;u t\u0131klay\u0131n.<\/li>\n<li>&#8220;Ad&#8221; i\u00e7in bir ad verin (\u00f6rne\u011fin, &#8220;allow-ssh&#8221;).<\/li>\n<li>&#8220;A\u011f&#8221; olarak ilgili VPC a\u011f\u0131n\u0131 se\u00e7in.<\/li>\n<li>&#8220;\u00d6ncelik&#8221; i\u00e7in bir de\u011fer girin.<\/li>\n<li>&#8220;Trafik y\u00f6n\u00fc&#8221; olarak &#8220;Gelen&#8221; se\u00e7in.<\/li>\n<li>&#8220;Eylem e\u015fle\u015firse&#8221; olarak &#8220;\u0130zin ver&#8221; se\u00e7in.<\/li>\n<li>&#8220;Hedefler&#8221; olarak &#8220;A\u011fdaki t\u00fcm \u00f6rnekler&#8221; veya &#8220;Belirtilen hedef etiketleri&#8221; se\u00e7in (gereksinimlerinize ba\u011fl\u0131 olarak).<\/li>\n<li>&#8220;Kaynak filtre&#8221; olarak &#8220;IP aral\u0131klar\u0131&#8221; se\u00e7in ve &#8220;0.0.0.0\/0&#8221; yaz\u0131n (veya daha k\u0131s\u0131tl\u0131 bir IP aral\u0131\u011f\u0131 belirtin).<\/li>\n<li>&#8220;Protokoller ve portlar&#8221; b\u00f6l\u00fcm\u00fcnde &#8220;tcp&#8221; se\u00e7in ve &#8220;22&#8221; yaz\u0131n.<\/li>\n<li>&#8220;Olu\u015ftur&#8221;u t\u0131klay\u0131n.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>A\u011f Yap\u0131land\u0131rmas\u0131 Sorunlar\u0131 ve \u00c7\u00f6z\u00fcmleri<\/strong><\/p>\n<p>G\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131n do\u011fru yap\u0131land\u0131r\u0131ld\u0131\u011f\u0131ndan emin olduktan sonra, a\u011f yap\u0131land\u0131rmas\u0131 sorunlar\u0131n\u0131 incelemek \u00f6nemlidir. <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken, a\u011f yap\u0131land\u0131rmas\u0131n\u0131n do\u011fru oldu\u011fundan emin olmak, ba\u011flant\u0131 sorunlar\u0131n\u0131n b\u00fcy\u00fck bir b\u00f6l\u00fcm\u00fcn\u00fc ortadan kald\u0131rabilir.<\/p>\n<ul>\n<li><strong>NAT (Network Address Translation) Yap\u0131land\u0131rmas\u0131n\u0131 Kontrol Etme:<\/strong>NAT, \u00f6zel IP adreslerini genel IP adreslerine d\u00f6n\u00fc\u015ft\u00fcren bir a\u011f teknolojisidir. E\u011fer sunucunuz bir NAT cihaz\u0131n\u0131n (\u00f6rne\u011fin, evdeki bir y\u00f6nlendirici) arkas\u0131ndaysa, SSH trafi\u011finin do\u011fru \u015fekilde y\u00f6nlendirildi\u011finden emin olman\u0131z gerekir.\n<ul>\n<li><strong>Port Y\u00f6nlendirme (Port Forwarding) Ayarlar\u0131n\u0131 Kontrol Etme:<\/strong> Y\u00f6nlendiricinizin ayarlar\u0131nda, 22 numaral\u0131 port \u00fczerinden gelen TCP trafi\u011finin sunucunuzun \u00f6zel IP adresine y\u00f6nlendirildi\u011finden emin olun. Port y\u00f6nlendirme ayarlar\u0131 genellikle y\u00f6nlendiricinin web aray\u00fcz\u00fcnde &#8220;Port Y\u00f6nlendirme&#8221; veya &#8220;NAT&#8221; b\u00f6l\u00fcm\u00fcnde bulunur.<\/li>\n<li><strong>\u00c7ift NAT:<\/strong> \u00c7ift NAT, iki NAT cihaz\u0131n\u0131n art arda kullan\u0131lmas\u0131d\u0131r. Bu, ba\u011flant\u0131 sorunlar\u0131na yol a\u00e7abilir. E\u011fer \u00e7ift NAT kullan\u0131yorsan\u0131z, bir NAT cihaz\u0131n\u0131 k\u00f6pr\u00fc moduna (bridge mode) almay\u0131 veya DMZ (Demilitarized Zone) yap\u0131land\u0131rmas\u0131n\u0131 kullanmay\u0131 deneyebilirsiniz.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Port Y\u00f6nlendirme (Port Forwarding) Ayarlar\u0131n\u0131 Kontrol Etme:<\/strong>Port y\u00f6nlendirme, belirli bir port \u00fczerinden gelen trafi\u011fi belirli bir cihaza veya servise y\u00f6nlendirme i\u015flemidir. SSH ba\u011flant\u0131lar\u0131 i\u00e7in, 22 numaral\u0131 portun do\u011fru \u015fekilde y\u00f6nlendirildi\u011finden emin olmak \u00f6nemlidir.\n<ul>\n<li><strong>Y\u00f6nlendirici Ayarlar\u0131:<\/strong> Y\u00f6nlendiricinizin web aray\u00fcz\u00fcnde, 22 numaral\u0131 port \u00fczerinden gelen TCP trafi\u011finin sunucunuzun \u00f6zel IP adresine y\u00f6nlendirildi\u011finden emin olun.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Ayarlar\u0131:<\/strong> Hem y\u00f6nlendiricinizin g\u00fcvenlik duvar\u0131nda hem de sunucunuzdaki g\u00fcvenlik duvar\u0131nda, 22 numaral\u0131 port \u00fczerinden gelen trafi\u011fe izin verildi\u011finden emin olun.<\/li>\n<\/ul>\n<\/li>\n<li><strong>VPN (Virtual Private Network) Ba\u011flant\u0131 Sorunlar\u0131n\u0131 Giderme:<\/strong>VPN, internet \u00fczerinden g\u00fcvenli bir ba\u011flant\u0131 olu\u015fturman\u0131z\u0131 sa\u011flayan bir teknolojidir. E\u011fer bir VPN kullan\u0131yorsan\u0131z, VPN ba\u011flant\u0131s\u0131n\u0131n d\u00fczg\u00fcn \u00e7al\u0131\u015ft\u0131\u011f\u0131ndan ve SSH trafi\u011finin VPN \u00fczerinden do\u011fru \u015fekilde y\u00f6nlendirildi\u011finden emin olman\u0131z gerekir.\n<ul>\n<li><strong>VPN Ba\u011flant\u0131s\u0131n\u0131 Kontrol Etme:<\/strong> VPN ba\u011flant\u0131n\u0131z\u0131n aktif ve kararl\u0131 oldu\u011fundan emin olun. VPN istemcisinin do\u011fru yap\u0131land\u0131r\u0131ld\u0131\u011f\u0131ndan ve do\u011fru sunucuya ba\u011fland\u0131\u011f\u0131ndan emin olun.<\/li>\n<li><strong>VPN G\u00fcvenlik Duvar\u0131 Ayarlar\u0131:<\/strong> VPN sa\u011flay\u0131c\u0131n\u0131z\u0131n g\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131n SSH trafi\u011fini engellemedi\u011finden emin olun. Baz\u0131 VPN sa\u011flay\u0131c\u0131lar\u0131, belirli portlar\u0131 veya protokolleri engelleyebilir.<\/li>\n<li><strong>VPN Y\u00f6nlendirme Ayarlar\u0131:<\/strong> VPN istemcinizin, SSH trafi\u011fini VPN t\u00fcneli \u00fczerinden y\u00f6nlendirdi\u011finden emin olun. Baz\u0131 VPN istemcileri, trafi\u011fi varsay\u0131lan a\u011f ge\u00e7idi \u00fczerinden y\u00f6nlendirebilir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryolar:<\/strong><\/p>\n<ul>\n<li><strong>Senaryo 1:<\/strong> Bir kullan\u0131c\u0131, evinden sunucusuna ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak ba\u011flant\u0131 zaman a\u015f\u0131m\u0131na u\u011frar. \u0130nternet ba\u011flant\u0131s\u0131n\u0131 ve sunucunun a\u00e7\u0131k oldu\u011funu do\u011frular. Ancak, y\u00f6nlendiricinin port y\u00f6nlendirme ayarlar\u0131nda 22 numaral\u0131 portun y\u00f6nlendirilmedi\u011fini fark eder. Y\u00f6nlendiricide port y\u00f6nlendirme ayarlar\u0131n\u0131 yap\u0131land\u0131rarak sorunu \u00e7\u00f6zer.<\/li>\n<li><strong>Senaryo 2:<\/strong> Bir sistem y\u00f6neticisi, AWS&#8217;deki bir EC2 \u00f6rne\u011fine ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak ba\u011flant\u0131 reddedilir. G\u00fcvenlik grubu ayarlar\u0131n\u0131 kontrol eder ve gelen kurallarda SSH trafi\u011fine izin veren bir kural\u0131n olmad\u0131\u011f\u0131n\u0131 fark eder. Gelen kurallara SSH trafi\u011fine izin veren bir kural ekleyerek sorunu \u00e7\u00f6zer.<\/li>\n<li><strong>Senaryo 3:<\/strong> Bir geli\u015ftirici, bir VPN kullanarak sunucusuna ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak ba\u011flant\u0131 s\u00fcrekli olarak kesintiye u\u011frar. VPN ba\u011flant\u0131s\u0131n\u0131 kontrol eder ve ba\u011flant\u0131n\u0131n istikrars\u0131z oldu\u011funu fark eder. Farkl\u0131 bir VPN sunucusuna ba\u011flanmay\u0131 veya VPN protokol\u00fcn\u00fc de\u011fi\u015ftirmeyi dener ve ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/li>\n<\/ul>\n<p>Bu b\u00f6l\u00fcm, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap arayan kullan\u0131c\u0131lara g\u00fcvenlik duvar\u0131 ve a\u011f yap\u0131land\u0131rmas\u0131 ile ilgili sorunlar\u0131 anlamalar\u0131 ve gidermeleri i\u00e7in kapsaml\u0131 bir rehber sunmaktad\u0131r. G\u00fcvenlik duvar\u0131 t\u00fcrlerini, yayg\u0131n g\u00fcvenlik duvar\u0131 yaz\u0131l\u0131mlar\u0131n\u0131, bulut platformlar\u0131ndaki g\u00fcvenlik gruplar\u0131n\u0131, NAT yap\u0131land\u0131rmas\u0131n\u0131, port y\u00f6nlendirmeyi ve VPN ba\u011flant\u0131 sorunlar\u0131n\u0131 detayl\u0131 bir \u015fekilde inceledik. Bu bilgileri kullanarak, SSH ba\u011flant\u0131 sorunlar\u0131n\u0131n \u00f6nemli bir b\u00f6l\u00fcm\u00fcn\u00fc \u00e7\u00f6zebilir ve sunucunuza g\u00fcvenli bir \u015fekilde eri\u015febilirsiniz.<\/p>\n<h2 id=\"5-ssh-sunucu-yap-land-rmas-configuration-sorunlar-\"><span class=\"ez-toc-section\" id=\"5_SSH_Sunucu_Yapilandirmasi_Configuration_Sorunlari\"><\/span>5. SSH Sunucu Yap\u0131land\u0131rmas\u0131 (Configuration) Sorunlar\u0131<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>SSH ba\u011flant\u0131 problemleri s\u00f6z konusu oldu\u011funda, genellikle g\u00f6z ard\u0131 edilen ancak kritik bir alan da SSH sunucusunun yap\u0131land\u0131rmas\u0131d\u0131r. Sunucu taraf\u0131ndaki yanl\u0131\u015f veya hatal\u0131 yap\u0131land\u0131rmalar, istemci ba\u011flant\u0131lar\u0131n\u0131n ba\u015far\u0131s\u0131z olmas\u0131na, kimlik do\u011frulama sorunlar\u0131na veya beklenmedik ba\u011flant\u0131 kopmalar\u0131na yol a\u00e7abilir. Bu b\u00f6l\u00fcmde, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna odaklanarak, SSH sunucu yap\u0131land\u0131rmas\u0131yla ilgili sorunlar\u0131 ve bu sorunlar\u0131n nas\u0131l giderilece\u011fini detayl\u0131 bir \u015fekilde inceleyece\u011fiz. Amac\u0131m\u0131z, SSH sunucusunun yap\u0131land\u0131rmas\u0131n\u0131 derinlemesine anlaman\u0131za ve olas\u0131 sorunlar\u0131 etkili bir \u015fekilde te\u015fhis edip \u00e7\u00f6zmenize yard\u0131mc\u0131 olmakt\u0131r.<\/p>\n<p><strong>SSH Sunucu Yap\u0131land\u0131rma Dosyas\u0131 (sshd_config) ve \u00d6nemi<\/strong><\/p>\n<p>SSH sunucusunun davran\u0131\u015f\u0131n\u0131 kontrol eden ana yap\u0131land\u0131rma dosyas\u0131 <code>sshd_config<\/code> dosyas\u0131d\u0131r. Bu dosya, SSH sunucusunun hangi portu dinleyece\u011finden, hangi kimlik do\u011frulama y\u00f6ntemlerini kullanaca\u011f\u0131na, hangi \u015fifreleme algoritmalar\u0131n\u0131 destekleyece\u011fine ve daha bir\u00e7ok \u00f6nemli ayara kadar bir\u00e7ok parametreyi i\u00e7erir. <code>sshd_config<\/code> dosyas\u0131 genellikle <code>\/etc\/ssh\/<\/code> dizininde bulunur.<\/p>\n<p><strong><code>sshd_config<\/code> Dosyas\u0131n\u0131 \u0130nceleme ve D\u00fczenleme<\/strong><\/p>\n<p><code>sshd_config<\/code> dosyas\u0131n\u0131 incelemek ve d\u00fczenlemek i\u00e7in bir metin d\u00fczenleyici kullanman\u0131z gerekir. <code>nano<\/code>, <code>vim<\/code> veya <code>emacs<\/code> gibi komut sat\u0131r\u0131 metin d\u00fczenleyicileri veya daha grafiksel bir aray\u00fcz sunan bir metin d\u00fczenleyici kullanabilirsiniz. Dosyay\u0131 d\u00fczenlemeden \u00f6nce, her zaman bir yedek kopyas\u0131n\u0131 alman\u0131z \u00f6nerilir.<\/p>\n<pre><code class=\"lang-bash\">sudo cp <span class=\"hljs-regexp\">\/etc\/<\/span>ssh<span class=\"hljs-regexp\">\/sshd_config \/<\/span>etc<span class=\"hljs-regexp\">\/ssh\/<\/span>sshd_config.backup\r\nsudo nano <span class=\"hljs-regexp\">\/etc\/<\/span>ssh<span class=\"hljs-regexp\">\/sshd_config<\/span>\r\n<\/code><\/pre>\n<p><strong>\u00d6nemli <code>sshd_config<\/code> Parametreleri ve Anlamlar\u0131<\/strong><\/p>\n<p>A\u015fa\u011f\u0131da, <code>sshd_config<\/code> dosyas\u0131nda s\u0131k\u00e7a kar\u015f\u0131la\u015f\u0131lan ve SSH ba\u011flant\u0131 problemlerine neden olabilecek baz\u0131 \u00f6nemli parametreler ve anlamlar\u0131 yer almaktad\u0131r:<\/p>\n<table>\n<thead>\n<tr>\n<th>Parametre<\/th>\n<th>A\u00e7\u0131klama<\/th>\n<th>Olas\u0131 Sorunlar ve \u00c7\u00f6z\u00fcmleri<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><code>Port<\/code><\/td>\n<td>SSH sunucusunun dinleyece\u011fi port numaras\u0131n\u0131 belirtir. Varsay\u0131lan de\u011fer 22&#8217;dir.<\/td>\n<td><strong>Sorun:<\/strong> Yanl\u0131\u015f port numaras\u0131 belirtilmi\u015fse, istemciler sunucuya ba\u011flanamaz. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Do\u011fru port numaras\u0131n\u0131 (<code>Port 22<\/code> veya yap\u0131land\u0131r\u0131lm\u0131\u015fsa farkl\u0131 bir port) <code>sshd_config<\/code> dosyas\u0131na girin ve SSH servisini yeniden ba\u015flat\u0131n. G\u00fcvenlik duvar\u0131 ayarlar\u0131nda da bu yeni portun a\u00e7\u0131k oldu\u011fundan emin olun.<\/td>\n<\/tr>\n<tr>\n<td><code>ListenAddress<\/code><\/td>\n<td>SSH sunucusunun dinleyece\u011fi IP adreslerini belirtir. Birden fazla IP adresi belirtilebilir.<\/td>\n<td><strong>Sorun:<\/strong> Yanl\u0131\u015f IP adresi belirtilmi\u015fse, sunucu sadece belirli IP adreslerinden gelen ba\u011flant\u0131lar\u0131 kabul eder. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Sunucunun t\u00fcm IP adreslerinden gelen ba\u011flant\u0131lar\u0131 kabul etmesini istiyorsan\u0131z, <code>ListenAddress 0.0.0.0<\/code> veya <code>ListenAddress ::<\/code> (IPv6 i\u00e7in) kullan\u0131n. Belirli bir IP adresi belirtmek istiyorsan\u0131z, do\u011fru IP adresini girdi\u011finizden emin olun.<\/td>\n<\/tr>\n<tr>\n<td><code>PermitRootLogin<\/code><\/td>\n<td>Root kullan\u0131c\u0131s\u0131n\u0131n do\u011frudan SSH \u00fczerinden oturum a\u00e7\u0131p a\u00e7amayaca\u011f\u0131n\u0131 belirtir. De\u011ferler <code>yes<\/code>, <code>no<\/code> veya <code>prohibit-password<\/code> olabilir. <code>prohibit-password<\/code>, parola tabanl\u0131 kimlik do\u011frulamay\u0131 engeller, ancak anahtar tabanl\u0131 kimlik do\u011frulamaya izin verir.<\/td>\n<td><strong>Sorun:<\/strong> <code>PermitRootLogin no<\/code> olarak ayarlanm\u0131\u015fsa, root kullan\u0131c\u0131s\u0131 do\u011frudan oturum a\u00e7amaz. <strong>\u00c7\u00f6z\u00fcm:<\/strong> G\u00fcvenlik nedenleriyle <code>PermitRootLogin no<\/code> olarak b\u0131rak\u0131lmas\u0131 \u00f6nerilir. Root yetkilerine ihtiya\u00e7 duyulmas\u0131 halinde, normal bir kullan\u0131c\u0131 ile oturum a\u00e7\u0131p <code>sudo su -<\/code> komutu ile root yetkilerine y\u00fckseltin.<\/td>\n<\/tr>\n<tr>\n<td><code>PasswordAuthentication<\/code><\/td>\n<td>Parola tabanl\u0131 kimlik do\u011frulaman\u0131n etkin olup olmad\u0131\u011f\u0131n\u0131 belirtir. De\u011ferler <code>yes<\/code> veya <code>no<\/code> olabilir.<\/td>\n<td><strong>Sorun:<\/strong> <code>PasswordAuthentication no<\/code> olarak ayarlanm\u0131\u015fsa, parola tabanl\u0131 kimlik do\u011frulama kullan\u0131lamaz. <strong>\u00c7\u00f6z\u00fcm:<\/strong> G\u00fcvenlik nedenleriyle <code>PasswordAuthentication no<\/code> olarak ayarlanmas\u0131 ve anahtar tabanl\u0131 kimlik do\u011frulaman\u0131n kullan\u0131lmas\u0131 \u00f6nerilir. Parola tabanl\u0131 kimlik do\u011frulamaya ihtiya\u00e7 duyulmas\u0131 halinde <code>PasswordAuthentication yes<\/code> olarak ayarlay\u0131n (ancak g\u00fcvenlik risklerini g\u00f6z \u00f6n\u00fcnde bulundurun).<\/td>\n<\/tr>\n<tr>\n<td><code>AllowUsers<\/code><\/td>\n<td>SSH \u00fczerinden oturum a\u00e7mas\u0131na izin verilen kullan\u0131c\u0131 adlar\u0131n\u0131 belirtir. Birden fazla kullan\u0131c\u0131 ad\u0131 bo\u015flukla ayr\u0131larak belirtilebilir.<\/td>\n<td><strong>Sorun:<\/strong> Kullan\u0131c\u0131 ad\u0131 <code>AllowUsers<\/code> listesinde yer alm\u0131yorsa, oturum a\u00e7amaz. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Kullan\u0131c\u0131n\u0131n ad\u0131n\u0131 <code>AllowUsers<\/code> listesine ekleyin.<\/td>\n<\/tr>\n<tr>\n<td><code>DenyUsers<\/code><\/td>\n<td>SSH \u00fczerinden oturum a\u00e7mas\u0131 engellenen kullan\u0131c\u0131 adlar\u0131n\u0131 belirtir. Birden fazla kullan\u0131c\u0131 ad\u0131 bo\u015flukla ayr\u0131larak belirtilebilir.<\/td>\n<td><strong>Sorun:<\/strong> Kullan\u0131c\u0131 ad\u0131 <code>DenyUsers<\/code> listesinde yer al\u0131yorsa, oturum a\u00e7amaz. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Kullan\u0131c\u0131n\u0131n ad\u0131n\u0131 <code>DenyUsers<\/code> listesinden kald\u0131r\u0131n.<\/td>\n<\/tr>\n<tr>\n<td><code>AllowGroups<\/code><\/td>\n<td>SSH \u00fczerinden oturum a\u00e7mas\u0131na izin verilen grup adlar\u0131n\u0131 belirtir. Birden fazla grup ad\u0131 bo\u015flukla ayr\u0131larak belirtilebilir.<\/td>\n<td><strong>Sorun:<\/strong> Kullan\u0131c\u0131n\u0131n ait oldu\u011fu grup <code>AllowGroups<\/code> listesinde yer alm\u0131yorsa, oturum a\u00e7amaz. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Kullan\u0131c\u0131n\u0131n ait oldu\u011fu grubu <code>AllowGroups<\/code> listesine ekleyin.<\/td>\n<\/tr>\n<tr>\n<td><code>DenyGroups<\/code><\/td>\n<td>SSH \u00fczerinden oturum a\u00e7mas\u0131 engellenen grup adlar\u0131n\u0131 belirtir. Birden fazla grup ad\u0131 bo\u015flukla ayr\u0131larak belirtilebilir.<\/td>\n<td><strong>Sorun:<\/strong> Kullan\u0131c\u0131n\u0131n ait oldu\u011fu grup <code>DenyGroups<\/code> listesinde yer al\u0131yorsa, oturum a\u00e7amaz. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Kullan\u0131c\u0131n\u0131n ait oldu\u011fu grubu <code>DenyGroups<\/code> listesinden kald\u0131r\u0131n.<\/td>\n<\/tr>\n<tr>\n<td><code>PubkeyAuthentication<\/code><\/td>\n<td>Anahtar tabanl\u0131 kimlik do\u011frulaman\u0131n etkin olup olmad\u0131\u011f\u0131n\u0131 belirtir. De\u011ferler <code>yes<\/code> veya <code>no<\/code> olabilir.<\/td>\n<td><strong>Sorun:<\/strong> <code>PubkeyAuthentication no<\/code> olarak ayarlanm\u0131\u015fsa, anahtar tabanl\u0131 kimlik do\u011frulama kullan\u0131lamaz. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>PubkeyAuthentication yes<\/code> olarak ayarlay\u0131n ve kullan\u0131c\u0131n\u0131n genel anahtar\u0131n\u0131n <code>authorized_keys<\/code> dosyas\u0131na do\u011fru \u015fekilde eklendi\u011finden emin olun.<\/td>\n<\/tr>\n<tr>\n<td><code>AuthorizedKeysFile<\/code><\/td>\n<td>Kullan\u0131c\u0131lar\u0131n genel anahtarlar\u0131n\u0131n sakland\u0131\u011f\u0131 <code>authorized_keys<\/code> dosyas\u0131n\u0131n konumunu belirtir. Varsay\u0131lan de\u011fer <code>.ssh\/authorized_keys<\/code>&#8216;dir.<\/td>\n<td><strong>Sorun:<\/strong> <code>AuthorizedKeysFile<\/code> yanl\u0131\u015f bir konumu g\u00f6steriyorsa, SSH sunucusu genel anahtarlar\u0131 bulamaz ve anahtar tabanl\u0131 kimlik do\u011frulama ba\u015far\u0131s\u0131z olur. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>AuthorizedKeysFile<\/code>&#8216;\u0131n do\u011fru konumu g\u00f6sterdi\u011finden emin olun. Kullan\u0131c\u0131n\u0131n ana dizinindeki <code>.ssh\/authorized_keys<\/code> dosyas\u0131n\u0131n do\u011fru izinlere sahip oldu\u011fundan ve genel anahtarlar\u0131n do\u011fru \u015fekilde eklendi\u011finden emin olun.<\/td>\n<\/tr>\n<tr>\n<td><code>MaxAuthTries<\/code><\/td>\n<td>\u0130zin verilen maksimum kimlik do\u011frulama denemesi say\u0131s\u0131n\u0131 belirtir.<\/td>\n<td><strong>Sorun:<\/strong> \u00c7ok fazla yanl\u0131\u015f kimlik do\u011frulama denemesi yap\u0131lmas\u0131 durumunda ba\u011flant\u0131 engellenebilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>MaxAuthTries<\/code> de\u011ferini makul bir seviyeye ayarlay\u0131n. \u00c7ok d\u00fc\u015f\u00fck bir de\u011fer, kullan\u0131c\u0131lar\u0131n yanl\u0131\u015fl\u0131kla engellenmesine neden olabilir.<\/td>\n<\/tr>\n<tr>\n<td><code>ClientAliveInterval<\/code><\/td>\n<td>SSH sunucusunun istemciye canl\u0131l\u0131k sinyali g\u00f6nderme aral\u0131\u011f\u0131n\u0131 (saniye cinsinden) belirtir.<\/td>\n<td><strong>Sorun:<\/strong> Ba\u011flant\u0131lar\u0131n bo\u015fta kalma s\u00fcresi nedeniyle kesilmesi durumunda, bu parametre ile ba\u011flant\u0131n\u0131n canl\u0131 tutulmas\u0131 sa\u011flanabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>ClientAliveInterval<\/code> de\u011ferini d\u00fc\u015f\u00fck bir de\u011fere ayarlay\u0131n (\u00f6rne\u011fin, <code>ClientAliveInterval 60<\/code>).<\/td>\n<\/tr>\n<tr>\n<td><code>ClientAliveCountMax<\/code><\/td>\n<td>SSH sunucusunun istemciden yan\u0131t almadan ba\u011flant\u0131y\u0131 kesmeden \u00f6nce g\u00f6nderece\u011fi canl\u0131l\u0131k sinyali say\u0131s\u0131n\u0131 belirtir.<\/td>\n<td><strong>Sorun:<\/strong> Ba\u011flant\u0131lar\u0131n bo\u015fta kalma s\u00fcresi nedeniyle kesilmesi durumunda, bu parametre ile ba\u011flant\u0131n\u0131n canl\u0131 tutulmas\u0131 sa\u011flanabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>ClientAliveCountMax<\/code> de\u011ferini makul bir de\u011fere ayarlay\u0131n (\u00f6rne\u011fin, <code>ClientAliveCountMax 3<\/code>).<\/td>\n<\/tr>\n<tr>\n<td><code>TCPKeepAlive<\/code><\/td>\n<td>TCP keep-alive mesajlar\u0131n\u0131n etkin olup olmad\u0131\u011f\u0131n\u0131 belirtir. De\u011ferler <code>yes<\/code> veya <code>no<\/code> olabilir.<\/td>\n<td><strong>Sorun:<\/strong> Ba\u011flant\u0131lar\u0131n bo\u015fta kalma s\u00fcresi nedeniyle kesilmesi durumunda, bu parametre ile ba\u011flant\u0131n\u0131n canl\u0131 tutulmas\u0131 sa\u011flanabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>TCPKeepAlive yes<\/code> olarak ayarlay\u0131n.<\/td>\n<\/tr>\n<tr>\n<td><code>GSSAPIAuthentication<\/code><\/td>\n<td>GSSAPI (Generic Security Services Application Program Interface) kimlik do\u011frulamas\u0131n\u0131n etkin olup olmad\u0131\u011f\u0131n\u0131 belirtir. De\u011ferler <code>yes<\/code> veya <code>no<\/code> olabilir.<\/td>\n<td><strong>Sorun:<\/strong> GSSAPI ile ilgili sorunlar ya\u015fanmas\u0131 durumunda, bu parametre devre d\u0131\u015f\u0131 b\u0131rak\u0131labilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> GSSAPI kullan\u0131lm\u0131yorsa <code>GSSAPIAuthentication no<\/code> olarak ayarlay\u0131n.<\/td>\n<\/tr>\n<tr>\n<td><code>KexAlgorithms<\/code><\/td>\n<td>Anahtar de\u011fi\u015fim algoritmalar\u0131n\u0131 belirtir.<\/td>\n<td><strong>Sorun:<\/strong> \u0130stemci ve sunucu aras\u0131nda uyumsuz anahtar de\u011fi\u015fim algoritmalar\u0131 olmas\u0131 durumunda ba\u011flant\u0131 kurulamayabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> \u0130stemci ve sunucu taraf\u0131ndan desteklenen ortak algoritmalar\u0131 <code>KexAlgorithms<\/code> parametresinde belirtin.<\/td>\n<\/tr>\n<tr>\n<td><code>Ciphers<\/code><\/td>\n<td>\u015eifreleme algoritmalar\u0131n\u0131 belirtir.<\/td>\n<td><strong>Sorun:<\/strong> \u0130stemci ve sunucu aras\u0131nda uyumsuz \u015fifreleme algoritmalar\u0131 olmas\u0131 durumunda ba\u011flant\u0131 kurulamayabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> \u0130stemci ve sunucu taraf\u0131ndan desteklenen ortak algoritmalar\u0131 <code>Ciphers<\/code> parametresinde belirtin.<\/td>\n<\/tr>\n<tr>\n<td><code>MACs<\/code><\/td>\n<td>Mesaj kimlik do\u011frulama kodlar\u0131n\u0131 (MAC) belirtir.<\/td>\n<td><strong>Sorun:<\/strong> \u0130stemci ve sunucu aras\u0131nda uyumsuz MAC algoritmalar\u0131 olmas\u0131 durumunda ba\u011flant\u0131 kurulamayabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> \u0130stemci ve sunucu taraf\u0131ndan desteklenen ortak algoritmalar\u0131 <code>MACs<\/code> parametresinde belirtin.<\/td>\n<\/tr>\n<tr>\n<td><code>UseDNS<\/code><\/td>\n<td>Uzak ana bilgisayarlar\u0131n adlar\u0131n\u0131 \u00e7\u00f6z\u00fcmlemek i\u00e7in DNS kullan\u0131l\u0131p kullan\u0131lmayaca\u011f\u0131n\u0131 belirtir. De\u011ferler <code>yes<\/code> veya <code>no<\/code> olabilir.<\/td>\n<td><strong>Sorun:<\/strong> DNS \u00e7\u00f6z\u00fcmleme sorunlar\u0131 olmas\u0131 durumunda ba\u011flant\u0131 yava\u015flayabilir veya ba\u015far\u0131s\u0131z olabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> DNS \u00e7\u00f6z\u00fcmleme sorunlar\u0131 ya\u015fan\u0131yorsa, <code>UseDNS no<\/code> olarak ayarlayarak DNS \u00e7\u00f6z\u00fcmlemesini devre d\u0131\u015f\u0131 b\u0131rak\u0131n.<\/td>\n<\/tr>\n<tr>\n<td><code>Banner<\/code><\/td>\n<td>SSH ba\u011flant\u0131s\u0131 kuruldu\u011funda g\u00f6r\u00fcnt\u00fclenecek bir banner (uyar\u0131 mesaj\u0131) belirtir.<\/td>\n<td><strong>Sorun:<\/strong> Yanl\u0131\u015f yap\u0131land\u0131r\u0131lm\u0131\u015f bir banner ba\u011flant\u0131 sorunlar\u0131na neden olmaz, ancak g\u00fcvenlik a\u00e7\u0131\u011f\u0131 olu\u015fturabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Banner dosyas\u0131n\u0131n i\u00e7eri\u011fini dikkatlice kontrol edin ve gereksiz bilgileri kald\u0131rmay\u0131n.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>SSH Sunucu Loglar\u0131n\u0131 (Logs) \u0130nceleme ve Anlamland\u0131rma<\/strong><\/p>\n<p><strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusunun \u00f6nemli bir ad\u0131m\u0131 da SSH sunucu loglar\u0131n\u0131 incelemektir. SSH sunucu loglar\u0131, ba\u011flant\u0131 giri\u015fimleri, kimlik do\u011frulama i\u015flemleri, hatalar ve di\u011fer \u00f6nemli olaylar hakk\u0131nda bilgi i\u00e7erir. Bu loglar\u0131 inceleyerek, ba\u011flant\u0131 sorunlar\u0131n\u0131n nedenlerini belirleyebilir ve uygun \u00e7\u00f6z\u00fcmleri uygulayabilirsiniz.<\/p>\n<p><strong>Log Dosyalar\u0131n\u0131n Konumu<\/strong><\/p>\n<p>SSH sunucu loglar\u0131n\u0131n konumu, i\u015fletim sistemine ve yap\u0131land\u0131rmaya ba\u011fl\u0131 olarak de\u011fi\u015fir. Yayg\u0131n log dosyas\u0131 konumlar\u0131 \u015funlard\u0131r:<\/p>\n<ul>\n<li><strong>Debian\/Ubuntu:<\/strong> <code>\/var\/log\/auth.log<\/code> veya <code>\/var\/log\/syslog<\/code><\/li>\n<li><strong>CentOS\/RHEL:<\/strong> <code>\/var\/log\/secure<\/code><\/li>\n<li><strong>macOS:<\/strong> <code>\/var\/log\/system.log<\/code> (Konsol uygulamas\u0131 arac\u0131l\u0131\u011f\u0131yla g\u00f6r\u00fcnt\u00fclenebilir)<\/li>\n<\/ul>\n<p><strong>Loglar\u0131 \u0130nceleme Ara\u00e7lar\u0131<\/strong><\/p>\n<p>Loglar\u0131 incelemek i\u00e7in \u00e7e\u015fitli ara\u00e7lar kullanabilirsiniz. Komut sat\u0131r\u0131 ara\u00e7lar\u0131 (<code>cat<\/code>, <code>less<\/code>, <code>grep<\/code>, <code>awk<\/code>, <code>sed<\/code>) ve grafiksel log analiz ara\u00e7lar\u0131 (\u00f6rne\u011fin, Graylog, ELK Stack) mevcuttur.<\/p>\n<p><strong>\u00d6nemli Log Mesajlar\u0131 ve Anlamlar\u0131<\/strong><\/p>\n<p>A\u015fa\u011f\u0131da, SSH sunucu loglar\u0131nda s\u0131k\u00e7a kar\u015f\u0131la\u015f\u0131lan baz\u0131 \u00f6nemli mesajlar ve anlamlar\u0131 yer almaktad\u0131r:<\/p>\n<table>\n<thead>\n<tr>\n<th>Log Mesaj\u0131<\/th>\n<th>A\u00e7\u0131klama<\/th>\n<th>Olas\u0131 Nedenler ve \u00c7\u00f6z\u00fcmleri<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><code>Invalid user &lt;kullanici_adi&gt; from &lt;IP_adresi&gt;<\/code><\/td>\n<td>Ge\u00e7ersiz bir kullan\u0131c\u0131 ad\u0131 ile ba\u011flant\u0131 giri\u015fimi.<\/td>\n<td><strong>Neden:<\/strong> Kullan\u0131c\u0131 ad\u0131 yanl\u0131\u015f yaz\u0131lm\u0131\u015f olabilir veya sistemde mevcut olmayan bir kullan\u0131c\u0131 ad\u0131 deneniyor olabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Do\u011fru kullan\u0131c\u0131 ad\u0131n\u0131 kulland\u0131\u011f\u0131n\u0131zdan emin olun. E\u011fer sistemde mevcut olmayan bir kullan\u0131c\u0131 ad\u0131 deneniyorsa, g\u00fcvenlik \u00f6nlemlerinizi g\u00f6zden ge\u00e7irin (\u00f6rne\u011fin, Fail2ban kullanarak brute-force sald\u0131r\u0131lar\u0131n\u0131 engelleme).<\/td>\n<\/tr>\n<tr>\n<td><code>Failed password for invalid user &lt;kullanici_adi&gt; from &lt;IP_adresi&gt; port &lt;port_numarasi&gt; ssh2<\/code><\/td>\n<td>Ge\u00e7ersiz bir kullan\u0131c\u0131 ad\u0131 ile parola tabanl\u0131 kimlik do\u011frulama giri\u015fimi.<\/td>\n<td><strong>Neden:<\/strong> Kullan\u0131c\u0131 ad\u0131 yanl\u0131\u015f yaz\u0131lm\u0131\u015f olabilir veya sistemde mevcut olmayan bir kullan\u0131c\u0131 ad\u0131 deneniyor olabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Do\u011fru kullan\u0131c\u0131 ad\u0131n\u0131 kulland\u0131\u011f\u0131n\u0131zdan emin olun. E\u011fer sistemde mevcut olmayan bir kullan\u0131c\u0131 ad\u0131 deneniyorsa, g\u00fcvenlik \u00f6nlemlerinizi g\u00f6zden ge\u00e7irin (\u00f6rne\u011fin, Fail2ban kullanarak brute-force sald\u0131r\u0131lar\u0131n\u0131 engelleme).<\/td>\n<\/tr>\n<tr>\n<td><code>Failed password for &lt;kullanici_adi&gt; from &lt;IP_adresi&gt; port &lt;port_numarasi&gt; ssh2<\/code><\/td>\n<td>Ge\u00e7erli bir kullan\u0131c\u0131 ad\u0131 ile parola tabanl\u0131 kimlik do\u011frulama giri\u015fimi ba\u015far\u0131s\u0131z oldu.<\/td>\n<td><strong>Neden:<\/strong> \u015eifre yanl\u0131\u015f girilmi\u015f olabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Do\u011fru \u015fifreyi kulland\u0131\u011f\u0131n\u0131zdan emin olun. E\u011fer \u015fifreyi unuttuysan\u0131z, \u015fifre s\u0131f\u0131rlama y\u00f6ntemlerini kullan\u0131n.<\/td>\n<\/tr>\n<tr>\n<td><code>Accepted publickey for &lt;kullanici_adi&gt; from &lt;IP_adresi&gt; port &lt;port_numarasi&gt; ssh2: RSA SHA256:&lt;anahtar_parmakizi&gt;<\/code><\/td>\n<td>Anahtar tabanl\u0131 kimlik do\u011frulama ba\u015far\u0131l\u0131 oldu.<\/td>\n<td><strong>Neden:<\/strong> Kullan\u0131c\u0131, \u00f6zel anahtar\u0131 ile ba\u015far\u0131l\u0131 bir \u015fekilde kimli\u011fini do\u011frulad\u0131. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Bu mesaj, anahtar tabanl\u0131 kimlik do\u011frulaman\u0131n do\u011fru \u015fekilde \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131 g\u00f6sterir.<\/td>\n<\/tr>\n<tr>\n<td><code>Received disconnect from &lt;IP_adresi&gt; port &lt;port_numarasi&gt;:11: Bye Bye<\/code><\/td>\n<td>Ba\u011flant\u0131 istemci taraf\u0131ndan kapat\u0131ld\u0131.<\/td>\n<td><strong>Neden:<\/strong> \u0130stemci ba\u011flant\u0131y\u0131 manuel olarak kapatt\u0131 veya ba\u011flant\u0131 istemci taraf\u0131nda kesildi. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Bu mesaj genellikle bir sorun oldu\u011funu g\u00f6stermez. Ancak, s\u0131k s\u0131k tekrarl\u0131yorsa, istemci taraf\u0131ndaki ba\u011flant\u0131 sorunlar\u0131n\u0131 veya g\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131 kontrol edin.<\/td>\n<\/tr>\n<tr>\n<td><code>Connection closed by authenticating user &lt;kullanici_adi&gt; &lt;IP_adresi&gt; port &lt;port_numarasi&gt; [preauth]<\/code><\/td>\n<td>Ba\u011flant\u0131 kimlik do\u011frulama a\u015famas\u0131nda kapat\u0131ld\u0131.<\/td>\n<td><strong>Neden:<\/strong> Kimlik do\u011frulama ba\u015far\u0131s\u0131z oldu veya ba\u011flant\u0131 \u00e7ok fazla kimlik do\u011frulama denemesi nedeniyle kapat\u0131ld\u0131. <strong>\u00c7\u00f6z\u00fcm:<\/strong> Kullan\u0131c\u0131n\u0131n do\u011fru kimlik bilgilerini kulland\u0131\u011f\u0131ndan emin olun. <code>MaxAuthTries<\/code> parametresinin \u00e7ok d\u00fc\u015f\u00fck ayarlanmad\u0131\u011f\u0131ndan emin olun. G\u00fcvenlik \u00f6nlemlerinizi g\u00f6zden ge\u00e7irin (\u00f6rne\u011fin, Fail2ban kullanarak brute-force sald\u0131r\u0131lar\u0131n\u0131 engelleme).<\/td>\n<\/tr>\n<tr>\n<td><code>reverse mapping checking getaddrinfo for &lt;ana_bilgisayar_adi&gt; [&lt;IP_adresi&gt;] failed - POSSIBLE BREAK-IN ATTEMPT!<\/code><\/td>\n<td>Ters DNS \u00e7\u00f6z\u00fcmlemesi ba\u015far\u0131s\u0131z oldu.<\/td>\n<td><strong>Neden:<\/strong> Sunucu, istemcinin IP adresini ana bilgisayar ad\u0131na \u00e7\u00f6z\u00fcmleyemedi. Bu, potansiyel bir g\u00fcvenlik tehdidi olarak de\u011ferlendirilebilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>UseDNS no<\/code> olarak ayarlayarak DNS \u00e7\u00f6z\u00fcmlemesini devre d\u0131\u015f\u0131 b\u0131rak\u0131n. Ancak, bu, baz\u0131 durumlarda ba\u011flant\u0131 h\u0131z\u0131n\u0131 etkileyebilir.<\/td>\n<\/tr>\n<tr>\n<td><code>error: kex_exchange_identification: Connection closed by remote host<\/code><\/td>\n<td>Anahtar de\u011fi\u015fim a\u015famas\u0131nda ba\u011flant\u0131 uzaktaki sunucu taraf\u0131ndan kapat\u0131ld\u0131.<\/td>\n<td><strong>Neden:<\/strong> \u0130stemci ve sunucu aras\u0131nda uyumsuz anahtar de\u011fi\u015fim algoritmalar\u0131 olabilir. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>KexAlgorithms<\/code> parametresini kontrol edin ve istemci ve sunucu taraf\u0131ndan desteklenen ortak algoritmalar\u0131 belirtin. \u0130stemci ve sunucu aras\u0131ndaki SSH s\u00fcr\u00fcmlerinin uyumlu oldu\u011fundan emin olun.<\/td>\n<\/tr>\n<tr>\n<td><code>Too many authentication failures for &lt;kullanici_adi&gt; from &lt;IP_adresi&gt; port &lt;port_numarasi&gt; ssh2 [preauth]<\/code><\/td>\n<td>\u00c7ok fazla kimlik do\u011frulama denemesi yap\u0131ld\u0131.<\/td>\n<td><strong>Neden:<\/strong> Kullan\u0131c\u0131 \u00e7ok fazla yanl\u0131\u015f parola veya anahtar denemesi yapt\u0131 ve ba\u011flant\u0131 engellendi. <strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>MaxAuthTries<\/code> parametresini kontrol edin ve makul bir de\u011fere ayarlay\u0131n. G\u00fcvenlik \u00f6nlemlerinizi g\u00f6zden ge\u00e7irin (\u00f6rne\u011fin, Fail2ban kullanarak brute-force sald\u0131r\u0131lar\u0131n\u0131 engelleme).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>SSH Servisini Yeniden Ba\u015flatma<\/strong><\/p>\n<p><code>sshd_config<\/code> dosyas\u0131nda herhangi bir de\u011fi\u015fiklik yapt\u0131ktan sonra, de\u011fi\u015fikliklerin etkin olmas\u0131 i\u00e7in SSH servisini yeniden ba\u015flatman\u0131z gerekir. SSH servisini yeniden ba\u015flatmak i\u00e7in a\u015fa\u011f\u0131daki komutlardan birini kullanabilirsiniz:<\/p>\n<pre><code class=\"lang-bash\">sudo systemctl restart sshd  # Systemd kullanan sistemlerde (\u00f6rne\u011f<span class=\"hljs-keyword\">in<\/span>, Ubuntu, CentOS <span class=\"hljs-number\">7<\/span>+)\r\nsudo service ssh restart     # SysVinit kullanan sistemlerde (\u00f6rne\u011f<span class=\"hljs-keyword\">in<\/span>, CentOS <span class=\"hljs-number\">6<\/span>)\r\n<\/code><\/pre>\n<p><strong>Dikkat Edilmesi Gereken G\u00fcvenlik Hususlar\u0131<\/strong><\/p>\n<p><code>sshd_config<\/code> dosyas\u0131n\u0131 d\u00fczenlerken, g\u00fcvenlik hususlar\u0131na dikkat etmek \u00f6nemlidir. Yanl\u0131\u015f yap\u0131land\u0131rmalar sunucunuzu g\u00fcvenlik a\u00e7\u0131klar\u0131na kar\u015f\u0131 savunmas\u0131z hale getirebilir. \u0130\u015fte dikkate alman\u0131z gereken baz\u0131 \u00f6nemli g\u00fcvenlik hususlar\u0131:<\/p>\n<ul>\n<li><strong>Parola Tabanl\u0131 Kimlik Do\u011frulamay\u0131 Devre D\u0131\u015f\u0131 B\u0131rak\u0131n:<\/strong> <code>PasswordAuthentication no<\/code> olarak ayarlayarak parola tabanl\u0131 kimlik do\u011frulamay\u0131 devre d\u0131\u015f\u0131 b\u0131rak\u0131n ve anahtar tabanl\u0131 kimlik do\u011frulamay\u0131 kullan\u0131n.<\/li>\n<li><strong>Root Giri\u015fini Engelleyin:<\/strong> <code>PermitRootLogin no<\/code> olarak ayarlayarak root kullan\u0131c\u0131s\u0131n\u0131n do\u011frudan oturum a\u00e7mas\u0131n\u0131 engelleyin.<\/li>\n<li><strong>G\u00fc\u00e7l\u00fc \u015eifreleme Algoritmalar\u0131 Kullan\u0131n:<\/strong> <code>KexAlgorithms<\/code>, <code>Ciphers<\/code> ve <code>MACs<\/code> parametrelerinde g\u00fc\u00e7l\u00fc ve g\u00fcncel \u015fifreleme algoritmalar\u0131 kullan\u0131n.<\/li>\n<li><strong>Gereksiz \u00d6zellikleri Devre D\u0131\u015f\u0131 B\u0131rak\u0131n:<\/strong> GSSAPI kimlik do\u011frulamas\u0131 veya DNS \u00e7\u00f6z\u00fcmlemesi gibi gereksiz \u00f6zellikleri devre d\u0131\u015f\u0131 b\u0131rak\u0131n.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Kullan\u0131n:<\/strong> SSH trafi\u011fini yaln\u0131zca belirli IP adreslerinden veya a\u011flardan gelen ba\u011flant\u0131lara izin verecek \u015fekilde yap\u0131land\u0131r\u0131lm\u0131\u015f bir g\u00fcvenlik duvar\u0131 kullan\u0131n.<\/li>\n<li><strong>G\u00fcnl\u00fckleri D\u00fczenli Olarak \u0130zleyin:<\/strong> SSH sunucu loglar\u0131n\u0131 d\u00fczenli olarak izleyerek potansiyel g\u00fcvenlik tehditlerini veya sorunlar\u0131 tespit edin.<\/li>\n<li><strong>Fail2ban Kullan\u0131n:<\/strong> Fail2ban gibi bir ara\u00e7 kullanarak brute-force sald\u0131r\u0131lar\u0131n\u0131 otomatik olarak engelleyin.<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryolar ve \u00c7\u00f6z\u00fcmleri<\/strong><\/p>\n<p>A\u015fa\u011f\u0131da, SSH sunucu yap\u0131land\u0131rmas\u0131yla ilgili yayg\u0131n sorunlar ve \u00e7\u00f6z\u00fcm \u00f6nerileri bulunmaktad\u0131r:<\/p>\n<ul>\n<li><strong>Senaryo 1:<\/strong> Kullan\u0131c\u0131, sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak &#8220;Connection refused&#8221; hatas\u0131 al\u0131r.\n<ul>\n<li><strong>Olas\u0131 Neden:<\/strong> SSH sunucusu \u00e7al\u0131\u015fm\u0131yor olabilir veya g\u00fcvenlik duvar\u0131 ba\u011flant\u0131y\u0131 engelliyor olabilir.<\/li>\n<li><strong>\u00c7\u00f6z\u00fcm:<\/strong> SSH sunucusunun \u00e7al\u0131\u015ft\u0131\u011f\u0131ndan emin olun (<code>sudo systemctl status sshd<\/code>). G\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131 kontrol edin ve 22 numaral\u0131 portun (veya yap\u0131land\u0131r\u0131lm\u0131\u015fsa farkl\u0131 bir portun) a\u00e7\u0131k oldu\u011fundan emin olun.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Senaryo 2:<\/strong> Kullan\u0131c\u0131, sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak &#8220;Permission denied (publickey)&#8221; hatas\u0131 al\u0131r.\n<ul>\n<li><strong>Olas\u0131 Neden:<\/strong> Anahtar tabanl\u0131 kimlik do\u011frulama etkin, ancak kullan\u0131c\u0131n\u0131n genel anahtar\u0131 <code>authorized_keys<\/code> dosyas\u0131na do\u011fru \u015fekilde eklenmemi\u015f olabilir.<\/li>\n<li><strong>\u00c7\u00f6z\u00fcm:<\/strong> Kullan\u0131c\u0131n\u0131n genel anahtar\u0131n\u0131n <code>authorized_keys<\/code> dosyas\u0131na do\u011fru \u015fekilde eklendi\u011finden ve dosyan\u0131n do\u011fru izinlere sahip oldu\u011fundan emin olun. <code>PubkeyAuthentication yes<\/code> olarak ayarland\u0131\u011f\u0131ndan emin olun.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Senaryo 3:<\/strong> Kullan\u0131c\u0131, sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak ba\u011flant\u0131 s\u00fcrekli olarak kesintiye u\u011frar.\n<ul>\n<li><strong>Olas\u0131 Neden:<\/strong> Ba\u011flant\u0131 bo\u015fta kalma s\u00fcresi nedeniyle kesiliyor olabilir.<\/li>\n<li><strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>ClientAliveInterval<\/code> ve <code>ClientAliveCountMax<\/code> parametrelerini yap\u0131land\u0131rarak ba\u011flant\u0131n\u0131n canl\u0131 tutulmas\u0131n\u0131 sa\u011flay\u0131n. <code>TCPKeepAlive yes<\/code> olarak ayarlay\u0131n.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Senaryo 4:<\/strong> Kullan\u0131c\u0131, sunucuya ba\u011flanmaya \u00e7al\u0131\u015f\u0131r ancak \u00e7ok yava\u015f bir ba\u011flant\u0131 h\u0131z\u0131yla kar\u015f\u0131la\u015f\u0131yor.\n<ul>\n<li><strong>Olas\u0131 Neden:<\/strong> DNS \u00e7\u00f6z\u00fcmleme sorunlar\u0131 veya zay\u0131f \u015fifreleme algoritmalar\u0131 kullan\u0131l\u0131yor olabilir.<\/li>\n<li><strong>\u00c7\u00f6z\u00fcm:<\/strong> <code>UseDNS no<\/code> olarak ayarlayarak DNS \u00e7\u00f6z\u00fcmlemesini devre d\u0131\u015f\u0131 b\u0131rak\u0131n. <code>KexAlgorithms<\/code>, <code>Ciphers<\/code> ve <code>MACs<\/code> parametrelerinde daha h\u0131zl\u0131 ve verimli \u015fifreleme algoritmalar\u0131 kullan\u0131n.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>SSH sunucu yap\u0131land\u0131rmas\u0131, SSH ba\u011flant\u0131 problemlerini \u00e7\u00f6zmek i\u00e7in kritik bir aland\u0131r. <code>sshd_config<\/code> dosyas\u0131n\u0131 dikkatlice inceleyerek, \u00f6nemli parametreleri anlayarak ve loglar\u0131 d\u00fczenli olarak izleyerek, olas\u0131 sorunlar\u0131 etkili bir \u015fekilde te\u015fhis edebilir ve \u00e7\u00f6zebilirsiniz. G\u00fcvenlik hususlar\u0131na dikkat etmek ve \u00f6nerilen g\u00fcvenlik \u00f6nlemlerini uygulamak, sunucunuzun g\u00fcvenli\u011fini art\u0131rman\u0131za ve yetkisiz eri\u015fimi \u00f6nlemenize yard\u0131mc\u0131 olacakt\u0131r. <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken, sunucu yap\u0131land\u0131rmas\u0131na gereken \u00f6nemi vermek, sorunlar\u0131n b\u00fcy\u00fck bir b\u00f6l\u00fcm\u00fcn\u00fc ortadan kald\u0131rman\u0131za olanak sa\u011flayacakt\u0131r.<\/p>\n<h2 id=\"6-i-leri-d-zey-sorun-giderme-teknikleri\"><span class=\"ez-toc-section\" id=\"6_Ileri_Duzey_Sorun_Giderme_Teknikleri\"><\/span>6. \u0130leri D\u00fczey Sorun Giderme Teknikleri<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Temel kontroller, kimlik do\u011frulama ayarlar\u0131, g\u00fcvenlik duvar\u0131 konfig\u00fcrasyonlar\u0131 ve SSH sunucu yap\u0131land\u0131rmas\u0131 incelendikten sonra dahi <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna yan\u0131t bulunamam\u0131\u015fsa, daha ileri d\u00fczey sorun giderme tekniklerine ba\u015fvurmak gerekebilir. Bu b\u00f6l\u00fcmde, daha karma\u015f\u0131k ve nadir kar\u015f\u0131la\u015f\u0131lan sorunlara y\u00f6nelik \u00e7\u00f6z\u00fcm \u00f6nerileri sunulacak, a\u011f katman\u0131ndaki detayl\u0131 incelemelerden tutun da SSH protokol\u00fcn\u00fcn derinliklerine inen analizlere kadar \u00e7e\u015fitli y\u00f6ntemler ele al\u0131nacakt\u0131r. Bu ileri d\u00fczey teknikler, sistem y\u00f6neticileri ve deneyimli kullan\u0131c\u0131lar i\u00e7in tasarlanm\u0131\u015ft\u0131r ve daha derinlemesine bir teknik bilgi birikimi gerektirebilir.<\/p>\n<p><strong>MTU (Maximum Transmission Unit) Ayarlar\u0131n\u0131 Kontrol Etme<\/strong><\/p>\n<p>MTU (Maximum Transmission Unit), bir a\u011f \u00fczerinden tek bir pakette ta\u015f\u0131nabilecek en b\u00fcy\u00fck veri miktar\u0131n\u0131 ifade eder. Genellikle Ethernet a\u011flar\u0131nda MTU de\u011feri 1500 baytt\u0131r. Ancak, VPN ba\u011flant\u0131lar\u0131, PPPoE (Point-to-Point Protocol over Ethernet) gibi teknolojiler kullan\u0131ld\u0131\u011f\u0131nda veya farkl\u0131 a\u011f segmentleri aras\u0131nda ge\u00e7i\u015f yap\u0131ld\u0131\u011f\u0131nda MTU de\u011feri de\u011fi\u015febilir. Uyumsuz MTU de\u011ferleri, paketlerin par\u00e7alanmas\u0131na (fragmentation) veya tamamen kaybolmas\u0131na neden olabilir, bu da <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusunun bir cevab\u0131 olabilecek ba\u011flant\u0131 sorunlar\u0131na yol a\u00e7abilir.<\/p>\n<p><strong>MTU Uyumsuzlu\u011funun Belirtileri:<\/strong><\/p>\n<ul>\n<li>SSH ba\u011flant\u0131s\u0131 kuruluyor gibi g\u00f6r\u00fcn\u00fcr, ancak komutlar \u00e7al\u0131\u015ft\u0131r\u0131lamaz veya \u00e7ok yava\u015f \u00e7al\u0131\u015f\u0131r.<\/li>\n<li>Dosya transferleri ba\u015far\u0131s\u0131z olur veya \u00e7ok yava\u015f ilerler.<\/li>\n<li>Ba\u011flant\u0131 s\u00fcrekli olarak kesintiye u\u011frar.<\/li>\n<li>Ping testleri ba\u015far\u0131l\u0131 olurken, daha b\u00fcy\u00fck paket boyutlar\u0131yla yap\u0131lan ping testleri ba\u015far\u0131s\u0131z olur.<\/li>\n<\/ul>\n<p><strong>MTU De\u011ferini Kontrol Etme:<\/strong><\/p>\n<p>MTU de\u011ferini kontrol etmek i\u00e7in i\u015fletim sistemine \u00f6zg\u00fc komutlar kullan\u0131labilir.<\/p>\n<ul>\n<li><strong>Linux:<\/strong>\n<pre><code class=\"lang-bash\">ip link show <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">arayuz_adi<\/span>&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;arayuz_adi&gt;<\/code> yerine, a\u011f aray\u00fcz\u00fcn\u00fcn ad\u0131n\u0131 yaz\u0131n (\u00f6rne\u011fin, eth0, wlan0, tun0). \u00c7\u0131kt\u0131da &#8220;mtu&#8221; ifadesinin yan\u0131ndaki de\u011fer, aray\u00fcz\u00fcn MTU de\u011ferini g\u00f6sterir.<\/p>\n<p>\u00d6rnek \u00c7\u0131kt\u0131:<\/p>\n<pre><code><span class=\"hljs-number\">2<\/span>: eth0: <span class=\"hljs-variable\">&lt;BROADCAST,MULTICAST,UP,LOWER_UP&gt;<\/span> mtu <span class=\"hljs-number\">1500<\/span> qdisc pfifo_fast <span class=\"hljs-keyword\">state<\/span> UP mode DEFAULT <span class=\"hljs-keyword\">group<\/span> <span class=\"hljs-keyword\">default<\/span> qlen <span class=\"hljs-number\">1000<\/span>\r\n    link\/ether <span class=\"hljs-number\">00<\/span>:<span class=\"hljs-number\">11<\/span>:<span class=\"hljs-number\">22<\/span>:<span class=\"hljs-number\">33<\/span>:<span class=\"hljs-number\">44<\/span>:<span class=\"hljs-number\">55<\/span> brd ff:ff:ff:ff:ff:ff\r\n<\/code><\/pre>\n<\/li>\n<li><strong>Windows:<\/strong>\n<pre><code class=\"lang-powershell\"><span class=\"hljs-keyword\">Get<\/span>-NetAdapterAdvancedProperty -Name <span class=\"hljs-string\">\"Jumbo Packet\"<\/span> -InterfaceAlias <span class=\"hljs-string\">\"&lt;arayuz_adi&gt;\"<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;arayuz_adi&gt;<\/code> yerine, a\u011f aray\u00fcz\u00fcn\u00fcn ad\u0131n\u0131 yaz\u0131n (\u00f6rne\u011fin, Ethernet, Wi-Fi). \u00c7\u0131kt\u0131da &#8220;DisplayValue&#8221; ifadesinin yan\u0131ndaki de\u011fer, aray\u00fcz\u00fcn MTU de\u011ferini g\u00f6sterir.<\/p>\n<p>Ayr\u0131ca, <code>netsh<\/code> komutu da kullan\u0131labilir:<\/p>\n<pre><code class=\"lang-powershell\">netsh <span class=\"hljs-class\"><span class=\"hljs-keyword\">interface<\/span> <span class=\"hljs-title\">ipv4<\/span> <span class=\"hljs-title\">show<\/span> <span class=\"hljs-title\">subinterfaces<\/span><\/span>\r\n<\/code><\/pre>\n<p>\u00c7\u0131kt\u0131da &#8220;MTU&#8221; s\u00fctunundaki de\u011fer, aray\u00fcz\u00fcn MTU de\u011ferini g\u00f6sterir.<\/li>\n<li><strong>macOS:<\/strong>\n<pre><code class=\"lang-bash\">networksetup -getMTU <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">arayuz_adi<\/span>&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;arayuz_adi&gt;<\/code> yerine, a\u011f aray\u00fcz\u00fcn\u00fcn ad\u0131n\u0131 yaz\u0131n (\u00f6rne\u011fin, en0, en1). \u00c7\u0131kt\u0131da &#8220;MTU:&#8221; ifadesinin yan\u0131ndaki de\u011fer, aray\u00fcz\u00fcn MTU de\u011ferini g\u00f6sterir.<\/li>\n<\/ul>\n<p><strong>MTU De\u011ferini D\u00fc\u015f\u00fcrme:<\/strong><\/p>\n<p>MTU de\u011ferini d\u00fc\u015f\u00fcrmek, paketlerin par\u00e7alanmas\u0131n\u0131 \u00f6nleyerek ba\u011flant\u0131 sorunlar\u0131n\u0131 \u00e7\u00f6zebilir. MTU de\u011ferini d\u00fc\u015f\u00fcrmek i\u00e7in i\u015fletim sistemine \u00f6zg\u00fc komutlar kullan\u0131labilir.<\/p>\n<ul>\n<li><strong>Linux:<\/strong>\n<pre><code class=\"lang-bash\">sudo ip link <span class=\"hljs-built_in\">set<\/span> <span class=\"hljs-variable\">&lt;arayuz_adi&gt;<\/span> mtu <span class=\"hljs-variable\">&lt;yeni_mtu_degeri&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;arayuz_adi&gt;<\/code> yerine, a\u011f aray\u00fcz\u00fcn\u00fcn ad\u0131n\u0131 yaz\u0131n (\u00f6rne\u011fin, eth0, wlan0, tun0). <code>&lt;yeni_mtu_degeri&gt;<\/code> yerine, yeni MTU de\u011ferini yaz\u0131n (\u00f6rne\u011fin, 1400, 1300, 1200).<\/p>\n<p>\u00d6rne\u011fin:<\/p>\n<pre><code class=\"lang-bash\">sudo ip link <span class=\"hljs-keyword\">set<\/span> eth0 <span class=\"hljs-comment\">mtu 1400<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, eth0 aray\u00fcz\u00fcn\u00fcn MTU de\u011ferini 1400 bayta d\u00fc\u015f\u00fcr\u00fcr.<\/p>\n<p><strong>Not:<\/strong> Bu de\u011fi\u015fiklikler ge\u00e7icidir ve sistemi yeniden ba\u015flatt\u0131\u011f\u0131n\u0131zda kaybolur. Kal\u0131c\u0131 hale getirmek i\u00e7in, a\u011f yap\u0131land\u0131rma dosyas\u0131na (\u00f6rne\u011fin, <code>\/etc\/network\/interfaces<\/code> veya <code>\/etc\/netplan\/<\/code>) gerekli sat\u0131rlar\u0131 eklemeniz gerekir.<\/li>\n<li><strong>Windows:<\/strong>\n<pre><code class=\"lang-powershell\"><span class=\"hljs-keyword\">Set<\/span>-NetAdapterAdvancedProperty <span class=\"hljs-comment\">-Name<\/span> <span class=\"hljs-comment\">\"Jumbo Packet\"<\/span><span class=\"hljs-comment\"> -InterfaceAlias<\/span> <span class=\"hljs-comment\">\"&lt;arayuz_adi&gt;\"<\/span><span class=\"hljs-comment\"> -DisplayValue<\/span> <span class=\"hljs-comment\">\"&lt;yeni_mtu_degeri&gt;\"<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;arayuz_adi&gt;<\/code> yerine, a\u011f aray\u00fcz\u00fcn\u00fcn ad\u0131n\u0131 yaz\u0131n (\u00f6rne\u011fin, Ethernet, Wi-Fi). <code>&lt;yeni_mtu_degeri&gt;<\/code> yerine, yeni MTU de\u011ferini yaz\u0131n (\u00f6rne\u011fin, 1400, 1300, 1200).<\/p>\n<p>\u00d6rne\u011fin:<\/p>\n<pre><code class=\"lang-powershell\"><span class=\"hljs-keyword\">Set<\/span>-NetAdapterAdvancedProperty <span class=\"hljs-comment\">-Name<\/span> <span class=\"hljs-comment\">\"Jumbo Packet\"<\/span><span class=\"hljs-comment\"> -InterfaceAlias<\/span> <span class=\"hljs-comment\">\"Ethernet\"<\/span><span class=\"hljs-comment\"> -DisplayValue<\/span> <span class=\"hljs-comment\">\"1400\"<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, Ethernet aray\u00fcz\u00fcn\u00fcn MTU de\u011ferini 1400 bayta d\u00fc\u015f\u00fcr\u00fcr.<\/p>\n<p>Ayr\u0131ca, <code>netsh<\/code> komutu da kullan\u0131labilir:<\/p>\n<pre><code class=\"lang-powershell\">netsh interface ipv4 <span class=\"hljs-keyword\">set<\/span> subinterface <span class=\"hljs-comment\">\"&lt;arayuz_adi&gt;\"<\/span><span class=\"hljs-comment\"> mtu=&lt;yeni_mtu_degeri&gt; store=persistent<\/span>\r\n<\/code><\/pre>\n<\/li>\n<li><strong>macOS:<\/strong>\n<pre><code class=\"lang-bash\">sudo networksetup -setMTU <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">arayuz_adi<\/span>&gt;<\/span> <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">yeni_mtu_degeri<\/span>&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;arayuz_adi&gt;<\/code> yerine, a\u011f aray\u00fcz\u00fcn\u00fcn ad\u0131n\u0131 yaz\u0131n (\u00f6rne\u011fin, en0, en1). <code>&lt;yeni_mtu_degeri&gt;<\/code> yerine, yeni MTU de\u011ferini yaz\u0131n (\u00f6rne\u011fin, 1400, 1300, 1200).<\/p>\n<p>\u00d6rne\u011fin:<\/p>\n<pre><code class=\"lang-bash\">sudo networksetup -setMTU en0 <span class=\"hljs-number\">1400<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, en0 aray\u00fcz\u00fcn\u00fcn MTU de\u011ferini 1400 bayta d\u00fc\u015f\u00fcr\u00fcr.<\/li>\n<\/ul>\n<p><strong>Ping Testi ile MTU De\u011ferini Do\u011frulama:<\/strong><\/p>\n<p>MTU de\u011ferini d\u00fc\u015f\u00fcrd\u00fckten sonra, ping testi ile yeni MTU de\u011ferinin do\u011fru \u00e7al\u0131\u015f\u0131p \u00e7al\u0131\u015fmad\u0131\u011f\u0131n\u0131 do\u011frulayabilirsiniz. <code>-s<\/code> parametresi ile paket boyutunu belirterek ping komutunu kullan\u0131n. <code>-M do<\/code> parametresi, paketlerin par\u00e7alanmas\u0131n\u0131 engeller.<\/p>\n<pre><code class=\"lang-bash\">ping -<span class=\"hljs-keyword\">c<\/span> <span class=\"hljs-number\">3<\/span> -s <span class=\"hljs-symbol\">&lt;paket_boyutu&gt;<\/span> -M <span class=\"hljs-keyword\">do<\/span> <span class=\"hljs-symbol\">&lt;sunucu_adresi&gt;<\/span>\r\n<\/code><\/pre>\n<p><code>&lt;paket_boyutu&gt;<\/code> yerine, test etmek istedi\u011finiz paket boyutunu yaz\u0131n (MTU de\u011ferinden 28 bayt \u00e7\u0131karman\u0131z gerekir, \u00e7\u00fcnk\u00fc 20 bayt IP ba\u015fl\u0131\u011f\u0131 ve 8 bayt ICMP ba\u015fl\u0131\u011f\u0131 eklenir). <code>&lt;sunucu_adresi&gt;<\/code> yerine, sunucunun IP adresini veya alan ad\u0131n\u0131 yaz\u0131n.<\/p>\n<p>\u00d6rne\u011fin, MTU de\u011ferini 1400 olarak ayarlad\u0131ysan\u0131z, paket boyutunu 1372 olarak ayarlayabilirsiniz:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-built_in\">ping<\/span> -c <span class=\"hljs-number\">3<\/span> -s <span class=\"hljs-number\">1372<\/span> -M <span class=\"hljs-keyword\">do<\/span> example.com\r\n<\/code><\/pre>\n<p>E\u011fer ping testi ba\u015far\u0131l\u0131 olursa, MTU de\u011feri do\u011fru ayarlanm\u0131\u015f demektir. E\u011fer ping testi ba\u015far\u0131s\u0131z olursa, MTU de\u011ferini daha da d\u00fc\u015f\u00fcrmeyi deneyin.<\/p>\n<p><strong>\u00d6rnek Senaryo:<\/strong><\/p>\n<p>Bir kullan\u0131c\u0131, VPN ba\u011flant\u0131s\u0131 \u00fczerinden sunucusuna ba\u011flanmaya \u00e7al\u0131\u015f\u0131r, ancak SSH ba\u011flant\u0131s\u0131 kuruluyor gibi g\u00f6r\u00fcnse de komutlar \u00e7al\u0131\u015ft\u0131r\u0131lamaz veya \u00e7ok yava\u015f \u00e7al\u0131\u015f\u0131r. MTU de\u011ferini kontrol etti\u011finde, VPN aray\u00fcz\u00fcn\u00fcn MTU de\u011ferinin 1500 oldu\u011funu fark eder. VPN ba\u011flant\u0131s\u0131n\u0131n MTU de\u011ferini d\u00fc\u015f\u00fcrmesi gerekti\u011fini d\u00fc\u015f\u00fcnerek, VPN aray\u00fcz\u00fcn\u00fcn MTU de\u011ferini 1300&#8217;e d\u00fc\u015f\u00fcr\u00fcr. Ard\u0131ndan, ping testi ile yeni MTU de\u011ferinin do\u011fru \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131 do\u011frular. SSH ba\u011flant\u0131s\u0131 art\u0131k sorunsuz bir \u015fekilde \u00e7al\u0131\u015fmaktad\u0131r.<\/p>\n<p><strong>SSH T\u00fcnelleme (Tunneling) ve Port Y\u00f6nlendirme Sorunlar\u0131<\/strong><\/p>\n<p>SSH t\u00fcnelleme (tunneling) ve port y\u00f6nlendirme, SSH protokol\u00fcn\u00fcn g\u00fc\u00e7l\u00fc \u00f6zelliklerinden biridir. Bu \u00f6zellikler, a\u011f trafi\u011fini g\u00fcvenli bir t\u00fcnel \u00fczerinden y\u00f6nlendirmeyi ve yerel veya uzak portlara eri\u015fmeyi sa\u011flar. Ancak, yanl\u0131\u015f yap\u0131land\u0131r\u0131lm\u0131\u015f SSH t\u00fcnelleri ve port y\u00f6nlendirme ayarlar\u0131, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusunun bir cevab\u0131 olabilecek ba\u011flant\u0131 sorunlar\u0131na yol a\u00e7abilir.<\/p>\n<p><strong>SSH T\u00fcnelleme T\u00fcrleri:<\/strong><\/p>\n<ul>\n<li><strong>Yerel Port Y\u00f6nlendirme (Local Port Forwarding):<\/strong> Yerel makinedeki bir portu, uzak sunucudaki bir porta y\u00f6nlendirir. Bu, yerel makinedeki bir uygulamaya, uzak sunucudaki bir hizmete g\u00fcvenli bir \u015fekilde eri\u015fmesini sa\u011flar.Komut:\n<pre><code class=\"lang-bash\">ssh -L &lt;yerel_port&gt;<span class=\"hljs-symbol\">:&lt;hedef_adresi&gt;<\/span><span class=\"hljs-symbol\">:&lt;hedef_port&gt;<\/span> &lt;kullanici_adi&gt;@&lt;sunucu_adresi&gt;\r\n<\/code><\/pre>\n<p>\u00d6rne\u011fin:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-selector-tag\">ssh<\/span> <span class=\"hljs-selector-tag\">-L<\/span> 8080<span class=\"hljs-selector-pseudo\">:localhost<\/span><span class=\"hljs-selector-pseudo\">:80<\/span> <span class=\"hljs-selector-tag\">kullanici<\/span>@<span class=\"hljs-keyword\">example<\/span>.<span class=\"hljs-keyword\">com<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, yerel makinedeki 8080 portunu, uzak sunucudaki 80 portuna y\u00f6nlendirir. Yerel makinede <code>http:\/\/localhost:8080<\/code> adresine eri\u015fti\u011finizde, asl\u0131nda uzak sunucudaki 80 portuna eri\u015fmi\u015f olursunuz.<\/li>\n<li><strong>Uzak Port Y\u00f6nlendirme (Remote Port Forwarding):<\/strong> Uzak sunucudaki bir portu, yerel makinedeki bir porta y\u00f6nlendirir. Bu, uzak sunucudaki bir uygulamaya, yerel makinedeki bir hizmete g\u00fcvenli bir \u015fekilde eri\u015fmesini sa\u011flar.Komut:\n<pre><code class=\"lang-bash\">ssh -R &lt;uzak_port&gt;<span class=\"hljs-symbol\">:&lt;hedef_adresi&gt;<\/span><span class=\"hljs-symbol\">:&lt;hedef_port&gt;<\/span> &lt;kullanici_adi&gt;@&lt;sunucu_adresi&gt;\r\n<\/code><\/pre>\n<p>\u00d6rne\u011fin:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-selector-tag\">ssh<\/span> <span class=\"hljs-selector-tag\">-R<\/span> 8080<span class=\"hljs-selector-pseudo\">:localhost<\/span><span class=\"hljs-selector-pseudo\">:80<\/span> <span class=\"hljs-selector-tag\">kullanici<\/span>@<span class=\"hljs-keyword\">example<\/span>.<span class=\"hljs-keyword\">com<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, uzak sunucudaki 8080 portunu, yerel makinedeki 80 portuna y\u00f6nlendirir. Uzak sunucuda <code>http:\/\/localhost:8080<\/code> adresine eri\u015fti\u011finizde, asl\u0131nda yerel makinedeki 80 portuna eri\u015fmi\u015f olursunuz.<\/li>\n<li><strong>Dinamik Port Y\u00f6nlendirme (Dynamic Port Forwarding):<\/strong> Yerel makinede bir SOCKS proxy sunucusu olu\u015fturur. Bu, yerel makinedeki uygulamalar\u0131n, t\u00fcm trafi\u011fini uzak sunucu \u00fczerinden ge\u00e7irmesini sa\u011flar.Komut:\n<pre><code class=\"lang-bash\">ssh -D <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">yerel_port<\/span>&gt;<\/span> <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">kullanici_adi<\/span>&gt;<\/span>@<span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">sunucu_adresi<\/span>&gt;<\/span>\r\n<\/code><\/pre>\n<p>\u00d6rne\u011fin:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-selector-tag\">ssh<\/span> <span class=\"hljs-selector-tag\">-D<\/span> 1080 <span class=\"hljs-selector-tag\">kullanici<\/span>@<span class=\"hljs-keyword\">example<\/span>.<span class=\"hljs-keyword\">com<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, yerel makinedeki 1080 portunda bir SOCKS proxy sunucusu olu\u015fturur. Yerel makinedeki uygulamalar\u0131n SOCKS proxy ayarlar\u0131n\u0131 127.0.0.1:1080 olarak yap\u0131land\u0131rarak, t\u00fcm trafi\u011fini uzak sunucu \u00fczerinden ge\u00e7irebilirsiniz.<\/li>\n<\/ul>\n<p><strong>SSH T\u00fcnelleme Sorunlar\u0131n\u0131n Nedenleri:<\/strong><\/p>\n<ul>\n<li><strong>Yanl\u0131\u015f Port Numaralar\u0131:<\/strong> Y\u00f6nlendirilen port numaralar\u0131 yanl\u0131\u015f yap\u0131land\u0131r\u0131lm\u0131\u015f olabilir.<\/li>\n<li><strong>Port \u00c7ak\u0131\u015fmalar\u0131:<\/strong> Y\u00f6nlendirilen portlar ba\u015fka uygulamalar taraf\u0131ndan kullan\u0131l\u0131yor olabilir.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Engellemeleri:<\/strong> G\u00fcvenlik duvar\u0131, y\u00f6nlendirilen portlar \u00fczerinden gelen trafi\u011fi engelliyor olabilir.<\/li>\n<li><strong>DNS \u00c7\u00f6z\u00fcmleme Sorunlar\u0131:<\/strong> Hedef adres do\u011fru \u015fekilde \u00e7\u00f6z\u00fcmlenemiyor olabilir.<\/li>\n<li><strong><code>GatewayPorts<\/code> Yap\u0131land\u0131rmas\u0131:<\/strong> Uzak port y\u00f6nlendirme kullan\u0131l\u0131yorsa, <code>GatewayPorts<\/code> parametresi do\u011fru yap\u0131land\u0131r\u0131lmam\u0131\u015f olabilir.<\/li>\n<\/ul>\n<p><strong>SSH T\u00fcnelleme Sorunlar\u0131n\u0131 Giderme:<\/strong><\/p>\n<ul>\n<li><strong>Port Numaralar\u0131n\u0131 Kontrol Etme:<\/strong> Y\u00f6nlendirilen port numaralar\u0131n\u0131n do\u011fru oldu\u011fundan emin olun.<\/li>\n<li><strong>Port \u00c7ak\u0131\u015fmalar\u0131n\u0131 Kontrol Etme:<\/strong> Y\u00f6nlendirilen portlar\u0131n ba\u015fka uygulamalar taraf\u0131ndan kullan\u0131lmad\u0131\u011f\u0131ndan emin olun. <code>netstat -tulnp<\/code> (Linux) veya <code>Get-Process -Id (Get-NetTCPConnection -LocalPort &lt;port_numarasi&gt;).OwningProcess<\/code> (Windows) komutlar\u0131n\u0131 kullanarak portlar\u0131 dinleyen uygulamalar\u0131 kontrol edebilirsiniz.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Ayarlar\u0131n\u0131 Kontrol Etme:<\/strong> G\u00fcvenlik duvar\u0131 ayarlar\u0131nda, y\u00f6nlendirilen portlar \u00fczerinden gelen trafi\u011fe izin verildi\u011finden emin olun.<\/li>\n<li><strong>DNS \u00c7\u00f6z\u00fcmlemesini Kontrol Etme:<\/strong> Hedef adresin do\u011fru \u015fekilde \u00e7\u00f6z\u00fcmlendi\u011finden emin olun. <code>ping &lt;hedef_adresi&gt;<\/code> komutunu kullanarak hedef adrese eri\u015filebilirli\u011fi test edebilirsiniz.<\/li>\n<li><strong><code>GatewayPorts<\/code> Yap\u0131land\u0131rmas\u0131n\u0131 Kontrol Etme:<\/strong> Uzak port y\u00f6nlendirme kullan\u0131l\u0131yorsa, <code>GatewayPorts yes<\/code> olarak ayarlanm\u0131\u015fsa, uzak sunucudaki herhangi bir IP adresinden (0.0.0.0) gelen ba\u011flant\u0131lar\u0131 kabul edersiniz. <code>GatewayPorts clientspecified<\/code> olarak ayarlanm\u0131\u015fsa, yaln\u0131zca SSH ba\u011flant\u0131s\u0131n\u0131 kuran istemcinin belirtti\u011fi IP adresinden gelen ba\u011flant\u0131lar\u0131 kabul edersiniz. <code>GatewayPorts no<\/code> olarak ayarlanm\u0131\u015fsa, yaln\u0131zca uzak sunucudaki localhost (127.0.0.1) adresinden gelen ba\u011flant\u0131lar\u0131 kabul edersiniz.<code>sshd_config<\/code> dosyas\u0131n\u0131 d\u00fczenleyin:\n<pre><code class=\"lang-bash\">sudo nano <span class=\"hljs-regexp\">\/etc\/<\/span>ssh<span class=\"hljs-regexp\">\/sshd_config<\/span>\r\n<\/code><\/pre>\n<p><code>GatewayPorts<\/code> parametresini bulun ve uygun de\u011feri ayarlay\u0131n:<\/p>\n<pre><code><span class=\"hljs-attribute\">GatewayPorts<\/span> <span class=\"hljs-literal\">yes<\/span>\r\n<\/code><\/pre>\n<p>De\u011fi\u015fiklikleri kaydettikten sonra, SSH servisini yeniden ba\u015flat\u0131n:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo systemctl restart sshd<\/span>\r\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryo:<\/strong><\/p>\n<p>Bir geli\u015ftirici, yerel makinesindeki bir web taray\u0131c\u0131s\u0131 arac\u0131l\u0131\u011f\u0131yla uzak sunucudaki bir web uygulamas\u0131na eri\u015fmek ister. Yerel port y\u00f6nlendirme kullanarak, yerel makinesindeki 8080 portunu, uzak sunucudaki 80 portuna y\u00f6nlendirir. Ancak, web taray\u0131c\u0131s\u0131nda <code>http:\/\/localhost:8080<\/code> adresine eri\u015fmeye \u00e7al\u0131\u015ft\u0131\u011f\u0131nda ba\u011flant\u0131 ba\u015far\u0131s\u0131z olur. Port \u00e7ak\u0131\u015fmas\u0131n\u0131 kontrol etti\u011finde, 8080 portunun ba\u015fka bir uygulama taraf\u0131ndan kullan\u0131ld\u0131\u011f\u0131n\u0131 fark eder. Y\u00f6nlendirme komutundaki yerel portu 8081 olarak de\u011fi\u015ftirir ve web uygulamas\u0131na sorunsuz bir \u015fekilde eri\u015febilir.<\/p>\n<p><strong>TCP Keep-Alive ve SSH Ba\u011flant\u0131 Kopmalar\u0131<\/strong><\/p>\n<p>SSH ba\u011flant\u0131lar\u0131, uzun s\u00fcre bo\u015fta kald\u0131\u011f\u0131nda veya a\u011f ba\u011flant\u0131s\u0131nda ge\u00e7ici sorunlar ya\u015fand\u0131\u011f\u0131nda kopabilir. Bu durum, \u00f6zellikle mobil cihazlar veya istikrars\u0131z a\u011f ba\u011flant\u0131lar\u0131 \u00fczerinden SSH kullan\u0131rken s\u0131k\u00e7a kar\u015f\u0131la\u015f\u0131lan bir sorundur. TCP Keep-Alive mekanizmas\u0131, bu t\u00fcr ba\u011flant\u0131 kopmalar\u0131n\u0131 \u00f6nlemeye yard\u0131mc\u0131 olabilir.<\/p>\n<p><strong>TCP Keep-Alive Nedir?<\/strong><\/p>\n<p>TCP Keep-Alive, TCP ba\u011flant\u0131s\u0131n\u0131n aktif olup olmad\u0131\u011f\u0131n\u0131 d\u00fczenli olarak kontrol etmek i\u00e7in kullan\u0131lan bir mekanizmad\u0131r. Bu mekanizma, belirli aral\u0131klarla kar\u015f\u0131 tarafa k\u00fc\u00e7\u00fck paketler g\u00f6ndererek ba\u011flant\u0131n\u0131n hala aktif olup olmad\u0131\u011f\u0131n\u0131 kontrol eder. E\u011fer kar\u015f\u0131 taraftan yan\u0131t al\u0131namazsa, ba\u011flant\u0131 kopmu\u015f olarak kabul edilir ve kapat\u0131l\u0131r.<\/p>\n<p><strong>SSH&#8217;de TCP Keep-Alive&#8217;\u0131 Etkinle\u015ftirme:<\/strong><\/p>\n<p>SSH&#8217;de TCP Keep-Alive&#8217;\u0131 etkinle\u015ftirmek i\u00e7in hem istemci hem de sunucu taraf\u0131nda ayarlar yap\u0131lmas\u0131 gerekebilir.<\/p>\n<ul>\n<li><strong>\u0130stemci Taraf\u0131nda:<\/strong><code>~\/.ssh\/config<\/code> dosyas\u0131na a\u015fa\u011f\u0131daki sat\u0131rlar\u0131 ekleyin veya d\u00fczenleyin:\n<pre><code>Host *\r\n    ServerAliveInterval <span class=\"hljs-number\">60<\/span>\r\n    ServerAliveCountMax <span class=\"hljs-number\">3<\/span>\r\n<\/code><\/pre>\n<p><code>ServerAliveInterval<\/code>, sunucunun istemciye canl\u0131l\u0131k sinyali g\u00f6nderme aral\u0131\u011f\u0131n\u0131 (saniye cinsinden) belirtir. <code>ServerAliveCountMax<\/code>, istemcinin sunucudan yan\u0131t almadan ba\u011flant\u0131y\u0131 kesmeden \u00f6nce g\u00f6nderece\u011fi canl\u0131l\u0131k sinyali say\u0131s\u0131n\u0131 belirtir. Bu \u00f6rnekte, istemci her 60 saniyede bir sunucuya canl\u0131l\u0131k sinyali g\u00f6nderecek ve 3 kez yan\u0131t alamazsa ba\u011flant\u0131y\u0131 kesecektir.<\/li>\n<li><strong>Sunucu Taraf\u0131nda:<\/strong><code>\/etc\/ssh\/sshd_config<\/code> dosyas\u0131na a\u015fa\u011f\u0131daki sat\u0131rlar\u0131 ekleyin veya d\u00fczenleyin:\n<pre><code>ClientAliveInterval <span class=\"hljs-number\">60<\/span>\r\nClientAliveCountMax <span class=\"hljs-number\">3<\/span>\r\nTCPKeepAlive yes\r\n<\/code><\/pre>\n<p><code>ClientAliveInterval<\/code> ve <code>ClientAliveCountMax<\/code> parametreleri, istemci taraf\u0131ndaki parametrelerle ayn\u0131 anlama gelir. <code>TCPKeepAlive yes<\/code> parametresi, TCP Keep-Alive mekanizmas\u0131n\u0131 etkinle\u015ftirir.<\/p>\n<p>De\u011fi\u015fiklikleri kaydettikten sonra, SSH servisini yeniden ba\u015flat\u0131n:<\/p>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sudo systemctl restart sshd<\/span>\r\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryo:<\/strong><\/p>\n<p>Bir sistem y\u00f6neticisi, mobil cihaz\u0131 \u00fczerinden sunucusuna SSH ile ba\u011flan\u0131r, ancak s\u0131k s\u0131k ba\u011flant\u0131 kopmalar\u0131 ya\u015far. TCP Keep-Alive ayarlar\u0131n\u0131n etkin olmad\u0131\u011f\u0131n\u0131 fark eder. Hem istemci hem de sunucu taraf\u0131nda TCP Keep-Alive ayarlar\u0131n\u0131 yap\u0131land\u0131r\u0131r. Art\u0131k mobil cihaz\u0131 \u00fczerinden sunucusuna ba\u011fland\u0131\u011f\u0131nda ba\u011flant\u0131 kopmalar\u0131 ya\u015famaz.<\/p>\n<p><strong>SSH Protokol S\u00fcr\u00fcmlerini ve \u015eifreleme Algoritmalar\u0131n\u0131 \u0130nceleme<\/strong><\/p>\n<p>SSH protokol\u00fcn\u00fcn farkl\u0131 s\u00fcr\u00fcmleri (SSHv1, SSHv2) ve \u00e7e\u015fitli \u015fifreleme algoritmalar\u0131 (AES, ChaCha20, RSA, ECDSA) mevcuttur. \u0130stemci ve sunucu aras\u0131nda uyumsuz protokol s\u00fcr\u00fcmleri veya \u015fifreleme algoritmalar\u0131, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusunun bir cevab\u0131 olabilecek ba\u011flant\u0131 sorunlar\u0131na yol a\u00e7abilir.<\/p>\n<p><strong>SSH Protokol S\u00fcr\u00fcm\u00fcn\u00fc Kontrol Etme:<\/strong><\/p>\n<ul>\n<li><strong>\u0130stemci Taraf\u0131nda:<\/strong><code>-v<\/code> parametresi ile SSH komutunu kullanarak protokol s\u00fcr\u00fcm\u00fcn\u00fc belirtebilirsiniz:\n<pre><code class=\"lang-bash\">ssh -v <span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">kullanici_adi<\/span>&gt;<\/span>@<span class=\"hljs-tag\">&lt;<span class=\"hljs-name\">sunucu_adresi<\/span>&gt;<\/span>\r\n<\/code><\/pre>\n<p>\u00c7\u0131kt\u0131da, kullan\u0131lan protokol s\u00fcr\u00fcm\u00fc belirtilecektir.<\/li>\n<li><strong>Sunucu Taraf\u0131nda:<\/strong><code>sshd_config<\/code> dosyas\u0131nda <code>Protocol<\/code> parametresi ile hangi protokol s\u00fcr\u00fcmlerinin desteklenece\u011fini belirtebilirsiniz:\n<pre><code>Protocol <span class=\"hljs-number\">2<\/span>\r\n<\/code><\/pre>\n<p>Bu, yaln\u0131zca SSHv2&#8217;nin desteklendi\u011fi anlam\u0131na gelir. SSHv1&#8217;i de desteklemek i\u00e7in <code>Protocol 2,1<\/code> olarak ayarlayabilirsiniz, ancak SSHv1 g\u00fcvenlik a\u00e7\u0131klar\u0131 i\u00e7erdi\u011fi i\u00e7in \u00f6nerilmez.<\/li>\n<\/ul>\n<p><strong>\u015eifreleme Algoritmalar\u0131n\u0131 Kontrol Etme:<\/strong><\/p>\n<ul>\n<li><strong>\u0130stemci ve Sunucu Taraf\u0131nda:<\/strong><code>-Q<\/code> parametresi ile SSH komutunu kullanarak desteklenen \u015fifreleme algoritmalar\u0131n\u0131 listeleyebilirsiniz:\n<pre><code class=\"lang-bash\">ssh -Q kex,cipher,mac,<span class=\"hljs-built_in\">key<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, anahtar de\u011fi\u015fim algoritmalar\u0131n\u0131 (kex), \u015fifreleme algoritmalar\u0131n\u0131 (cipher), mesaj kimlik do\u011frulama kodlar\u0131n\u0131 (mac) ve anahtar algoritmalar\u0131n\u0131 (key) listeler.<\/p>\n<p>\u0130stemci ve sunucu taraf\u0131ndan desteklenen ortak algoritmalar\u0131 belirlemek i\u00e7in, her iki tarafta da bu komutu \u00e7al\u0131\u015ft\u0131r\u0131n ve \u00e7\u0131kt\u0131lar\u0131 kar\u015f\u0131la\u015ft\u0131r\u0131n.<\/li>\n<\/ul>\n<p><strong>Uyumsuzluk Sorunlar\u0131n\u0131 Giderme:<\/strong><\/p>\n<ul>\n<li><strong>Protokol S\u00fcr\u00fcm\u00fcn\u00fc G\u00fcncelleme:<\/strong> M\u00fcmk\u00fcnse, hem istemci hem de sunucu taraf\u0131nda en son SSH protokol s\u00fcr\u00fcm\u00fcn\u00fc (SSHv2) kullan\u0131n.<\/li>\n<li><strong>\u015eifreleme Algoritmalar\u0131n\u0131 G\u00fcncelleme:<\/strong> G\u00fcvenli ve g\u00fcncel \u015fifreleme algoritmalar\u0131n\u0131 kullan\u0131n. Zay\u0131f veya eski algoritmalar\u0131 devre d\u0131\u015f\u0131 b\u0131rak\u0131n.<\/li>\n<li><strong><code>sshd_config<\/code> Dosyas\u0131n\u0131 D\u00fczenleme:<\/strong> <code>KexAlgorithms<\/code>, <code>Ciphers<\/code> ve <code>MACs<\/code> parametrelerinde, istemci ve sunucu taraf\u0131ndan desteklenen ortak algoritmalar\u0131 belirtin.<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryo:<\/strong><\/p>\n<p>Bir kullan\u0131c\u0131, eski bir SSH istemcisi kullanarak sunucusuna ba\u011flanmaya \u00e7al\u0131\u015f\u0131r, ancak &#8220;no matching key exchange method found&#8221; hatas\u0131 al\u0131r. SSH protokol s\u00fcr\u00fcm\u00fcn\u00fc ve \u015fifreleme algoritmalar\u0131n\u0131 kontrol etti\u011finde, istemcinin ve sunucunun uyumsuz oldu\u011funu fark eder. SSH istemcisini g\u00fcnceller ve sunucudaki <code>KexAlgorithms<\/code> parametresini istemci taraf\u0131ndan desteklenen algoritmalar\u0131 i\u00e7erecek \u015fekilde d\u00fczenler. Ard\u0131ndan, ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/p>\n<p><strong>SSH&#8217;yi Do\u011frudan TCP Sarg\u0131lay\u0131c\u0131lar\u0131 (TCP Wrappers) ile K\u0131s\u0131tlama<\/strong><\/p>\n<p>TCP Sarg\u0131lay\u0131c\u0131lar\u0131 (TCP Wrappers), belirli hizmetlere eri\u015fimi IP adreslerine veya alan adlar\u0131na g\u00f6re k\u0131s\u0131tlamak i\u00e7in kullan\u0131lan bir g\u00fcvenlik mekanizmas\u0131d\u0131r. SSH&#8217;yi TCP Sarg\u0131lay\u0131c\u0131lar\u0131 ile k\u0131s\u0131tlamak, yetkisiz eri\u015fimi engellemeye yard\u0131mc\u0131 olabilir.<\/p>\n<p><strong>TCP Sarg\u0131lay\u0131c\u0131lar\u0131n\u0131 Yap\u0131land\u0131rma:<\/strong><\/p>\n<p>TCP Sarg\u0131lay\u0131c\u0131lar\u0131n\u0131 yap\u0131land\u0131rmak i\u00e7in <code>\/etc\/hosts.allow<\/code> ve <code>\/etc\/hosts.deny<\/code> dosyalar\u0131n\u0131 d\u00fczenlemeniz gerekir.<\/p>\n<ul>\n<li><strong>\/etc\/hosts.allow:<\/strong> Eri\u015fime izin verilen IP adreslerini veya alan adlar\u0131n\u0131 belirtir.<\/li>\n<li><strong>\/etc\/hosts.deny:<\/strong> Eri\u015fimi engellenen IP adreslerini veya alan adlar\u0131n\u0131 belirtir.<\/li>\n<\/ul>\n<p><strong>SSH&#8217;yi TCP Sarg\u0131lay\u0131c\u0131lar\u0131 ile K\u0131s\u0131tlama:<\/strong><\/p>\n<ol>\n<li><code>\/etc\/hosts.deny<\/code> dosyas\u0131na a\u015fa\u011f\u0131daki sat\u0131r\u0131 ekleyin:\n<pre><code>sshd: <span class=\"hljs-keyword\">ALL<\/span>\r\n<\/code><\/pre>\n<p>Bu, varsay\u0131lan olarak t\u00fcm IP adreslerinden gelen SSH eri\u015fimini engeller.<\/li>\n<li><code>\/etc\/hosts.allow<\/code> dosyas\u0131na, eri\u015fime izin vermek istedi\u011finiz IP adreslerini veya alan adlar\u0131n\u0131 ekleyin:\n<pre><code><span class=\"hljs-symbol\">sshd:<\/span> <span class=\"hljs-number\">192.168<\/span><span class=\"hljs-number\">.1<\/span><span class=\"hljs-number\">.0<\/span>\/<span class=\"hljs-number\">24<\/span>\r\n<span class=\"hljs-symbol\">sshd:<\/span> example.com\r\n<\/code><\/pre>\n<p>Bu, 192.168.1.0\/24 a\u011f\u0131ndan ve example.com alan ad\u0131ndan gelen SSH eri\u015fimine izin verir.<\/li>\n<\/ol>\n<p><strong>Dikkat Edilmesi Gerekenler:<\/strong><\/p>\n<ul>\n<li><code>\/etc\/hosts.allow<\/code> ve <code>\/etc\/hosts.deny<\/code> dosyalar\u0131ndaki kurallar yukar\u0131dan a\u015fa\u011f\u0131ya do\u011fru okunur. \u0130lk e\u015fle\u015fen kural uygulan\u0131r.<\/li>\n<li>Kurallar\u0131 dikkatlice yap\u0131land\u0131r\u0131n ve yanl\u0131\u015fl\u0131kla kendi eri\u015fiminizi engellememeye \u00f6zen g\u00f6sterin.<\/li>\n<li>TCP Sarg\u0131lay\u0131c\u0131lar\u0131, <code>UseTCPKeepAlives no<\/code> olarak ayarlanm\u0131\u015fsa d\u00fczg\u00fcn \u00e7al\u0131\u015fmayabilir.<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryo:<\/strong><\/p>\n<p>Bir sistem y\u00f6neticisi, sunucusuna yaln\u0131zca belirli bir IP adresinden eri\u015fime izin vermek ister. TCP Sarg\u0131lay\u0131c\u0131lar\u0131n\u0131 kullanarak SSH eri\u015fimini k\u0131s\u0131tlar. <code>\/etc\/hosts.deny<\/code> dosyas\u0131na <code>sshd: ALL<\/code> sat\u0131r\u0131n\u0131 ekler ve <code>\/etc\/hosts.allow<\/code> dosyas\u0131na kendi IP adresini ekler. Art\u0131k sunucusuna yaln\u0131zca kendi IP adresinden eri\u015filebilir, di\u011fer t\u00fcm IP adreslerinden gelen eri\u015fim engellenmi\u015ftir.<\/p>\n<p><strong>SELinux (Security-Enhanced Linux) ve AppArmor Sorunlar\u0131<\/strong><\/p>\n<p>SELinux ve AppArmor, Linux sistemlerde kullan\u0131lan g\u00fcvenlik mod\u00fclleridir. Bu mod\u00fcller, sistem kaynaklar\u0131na eri\u015fimi k\u0131s\u0131tlayarak g\u00fcvenli\u011fi art\u0131r\u0131r. Ancak, yanl\u0131\u015f yap\u0131land\u0131r\u0131lm\u0131\u015f SELinux veya AppArmor kurallar\u0131, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusunun bir cevab\u0131 olabilecek ba\u011flant\u0131 sorunlar\u0131na yol a\u00e7abilir.<\/p>\n<p><strong>SELinux ve AppArmor&#8217;un Etkin Olup Olmad\u0131\u011f\u0131n\u0131 Kontrol Etme:<\/strong><\/p>\n<ul>\n<li><strong>SELinux:<\/strong>\n<pre><code class=\"lang-bash\"><span class=\"hljs-attribute\">sestatus<\/span>\r\n<\/code><\/pre>\n<p>\u00c7\u0131kt\u0131da &#8220;SELinux status&#8221; ifadesinin yan\u0131ndaki de\u011fer, SELinux&#8217;un etkin olup olmad\u0131\u011f\u0131n\u0131 g\u00f6sterir (&#8220;enabled&#8221; veya &#8220;disabled&#8221;). &#8220;SELinux policy&#8221; ifadesinin yan\u0131ndaki de\u011fer, SELinux politikas\u0131n\u0131n modunu g\u00f6sterir (&#8220;enforcing&#8221;, &#8220;permissive&#8221; veya &#8220;disabled&#8221;).<\/li>\n<li><strong>AppArmor:<\/strong>\n<pre><code class=\"lang-bash\">apparmor_status\r\n<\/code><\/pre>\n<p>\u00c7\u0131kt\u0131da, AppArmor profillerinin listesi ve durumlar\u0131 g\u00f6sterilir.<\/li>\n<\/ul>\n<p><strong>SELinux ve AppArmor Sorunlar\u0131n\u0131 Giderme:<\/strong><\/p>\n<ul>\n<li><strong>SELinux&#8217;u Ge\u00e7ici Olarak Devre D\u0131\u015f\u0131 B\u0131rakma (Yaln\u0131zca Test Ama\u00e7l\u0131):<\/strong>\n<pre><code class=\"lang-bash\">sudo setenforce <span class=\"hljs-number\">0<\/span>\r\n<\/code><\/pre>\n<p>Bu komut, SELinux&#8217;u &#8220;permissive&#8221; moduna ge\u00e7irir. Bu, SELinux&#8217;un kurallar\u0131 ihlal eden i\u015flemleri engellemeyece\u011fi, ancak ihlalleri loglayaca\u011f\u0131 anlam\u0131na gelir.<\/p>\n<p><strong>Uyar\u0131:<\/strong> SELinux&#8217;u devre d\u0131\u015f\u0131 b\u0131rakmak, sisteminizin g\u00fcvenli\u011fini azalt\u0131r. Bu nedenle, yaln\u0131zca test ama\u00e7l\u0131 kullan\u0131n ve sorunu \u00e7\u00f6zd\u00fckten sonra SELinux&#8217;u tekrar etkinle\u015ftirin.<\/li>\n<li><strong>AppArmor&#8217;u Ge\u00e7ici Olarak Devre D\u0131\u015f\u0131 B\u0131rakma (Yaln\u0131zca Test Ama\u00e7l\u0131):<\/strong>\n<pre><code class=\"lang-bash\">sudo systemctl <span class=\"hljs-built_in\">stop<\/span> apparmor\r\n<\/code><\/pre>\n<p>Bu komut, AppArmor servisini durdurur.<\/p>\n<p><strong>Uyar\u0131:<\/strong> AppArmor&#8217;u devre d\u0131\u015f\u0131 b\u0131rakmak, sisteminizin g\u00fcvenli\u011fini azalt\u0131r. Bu nedenle, yaln\u0131zca test ama\u00e7l\u0131 kullan\u0131n ve sorunu \u00e7\u00f6zd\u00fckten sonra AppArmor&#8217;u tekrar etkinle\u015ftirin.<\/li>\n<li><strong>SELinux ve AppArmor Loglar\u0131n\u0131 \u0130nceleme:<\/strong>SELinux ve AppArmor loglar\u0131, kurallar\u0131 ihlal eden i\u015flemleri ve engellenen eri\u015fimleri g\u00f6sterir. Bu loglar\u0131 inceleyerek, hangi kurallar\u0131n SSH ba\u011flant\u0131 sorunlar\u0131na neden oldu\u011funu belirleyebilirsiniz.\n<ul>\n<li><strong>SELinux Loglar\u0131:<\/strong> <code>\/var\/log\/audit\/audit.log<\/code><\/li>\n<li><strong>AppArmor Loglar\u0131:<\/strong> <code>\/var\/log\/syslog<\/code> veya <code>\/var\/log\/kern.log<\/code><\/li>\n<\/ul>\n<\/li>\n<li><strong>\u00d6zel SELinux ve AppArmor Kurallar\u0131 Olu\u015fturma:<\/strong>SELinux ve AppArmor loglar\u0131n\u0131 inceledikten sonra, SSH&#8217;nin d\u00fczg\u00fcn \u00e7al\u0131\u015fmas\u0131n\u0131 sa\u011flayacak \u00f6zel kurallar olu\u015fturabilirsiniz. Bu, daha karma\u015f\u0131k bir i\u015flemdir ve SELinux ve AppArmor&#8217;un nas\u0131l \u00e7al\u0131\u015ft\u0131\u011f\u0131na dair derin bir anlay\u0131\u015f gerektirir.<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryo:<\/strong><\/p>\n<p>Bir sistem y\u00f6neticisi, sunucusuna SSH ile ba\u011flanmaya \u00e7al\u0131\u015f\u0131r, ancak ba\u011flant\u0131 reddedilir. SELinux&#8217;un etkin oldu\u011funu ve &#8220;enforcing&#8221; modunda \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131 fark eder. SELinux loglar\u0131n\u0131 inceledi\u011finde, SSH&#8217;nin belirli bir sistem kayna\u011f\u0131na eri\u015fiminin engellendi\u011fini g\u00f6r\u00fcr. \u00d6zel bir SELinux kural\u0131 olu\u015fturarak SSH&#8217;nin bu kayna\u011fa eri\u015fmesine izin verir. Ard\u0131ndan, ba\u011flant\u0131 sorunu \u00e7\u00f6z\u00fcl\u00fcr.<\/p>\n<p>Bu b\u00f6l\u00fcmde, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna y\u00f6nelik ileri d\u00fczey sorun giderme teknikleri ele al\u0131nm\u0131\u015ft\u0131r. MTU ayarlar\u0131n\u0131n kontrol\u00fc, SSH t\u00fcnelleme ve port y\u00f6nlendirme sorunlar\u0131n\u0131n giderilmesi, TCP Keep-Alive mekanizmas\u0131n\u0131n kullan\u0131lmas\u0131, SSH protokol s\u00fcr\u00fcmlerinin ve \u015fifreleme algoritmalar\u0131n\u0131n incelenmesi, TCP Sarg\u0131lay\u0131c\u0131lar\u0131n\u0131n kullan\u0131lmas\u0131 ve SELinux\/AppArmor sorunlar\u0131n\u0131n giderilmesi gibi \u00e7e\u015fitli konular detayl\u0131 bir \u015fekilde incelenmi\u015ftir. Bu teknikler, daha karma\u015f\u0131k ve nadir kar\u015f\u0131la\u015f\u0131lan sorunlara y\u00f6nelik \u00e7\u00f6z\u00fcm \u00f6nerileri sunmakta ve daha derinlemesine bir teknik bilgi birikimi gerektirmektedir. Bu bilgileri kullanarak, SSH ba\u011flant\u0131 sorunlar\u0131n\u0131n en karma\u015f\u0131k olanlar\u0131n\u0131 bile \u00e7\u00f6zebilir ve sunucunuza g\u00fcvenli bir \u015fekilde eri\u015febilirsiniz.<\/p>\n<h2 id=\"7-ek-kaynaklar-ve-yard-m-alma\"><span class=\"ez-toc-section\" id=\"7_Ek_Kaynaklar_ve_Yardim_Alma\"><\/span>7. Ek Kaynaklar ve Yard\u0131m Alma<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>SSH ba\u011flant\u0131 problemleriyle kar\u015f\u0131la\u015ft\u0131\u011f\u0131n\u0131zda, sorun giderme s\u00fcrecinde tak\u0131l\u0131p kalman\u0131z olduk\u00e7a olas\u0131d\u0131r. Temel ad\u0131mlar\u0131 denedikten ve bilinen \u00e7\u00f6z\u00fcmleri uygulad\u0131ktan sonra dahi sorun devam ediyorsa, daha fazla bilgiye ve yard\u0131ma ihtiya\u00e7 duyabilirsiniz. Bu b\u00f6l\u00fcmde, <strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken ba\u015fvurabilece\u011finiz ek kaynaklar\u0131 ve yard\u0131m alma y\u00f6ntemlerini detayl\u0131 bir \u015fekilde inceleyece\u011fiz. Amac\u0131m\u0131z, sizi do\u011fru kaynaklara y\u00f6nlendirerek, sorununuzu en k\u0131sa s\u00fcrede ve etkili bir \u015fekilde \u00e7\u00f6zmenize yard\u0131mc\u0131 olmakt\u0131r.<\/p>\n<p><strong>1. SSH Dok\u00fcmantasyonuna Ba\u015fvurma<\/strong><\/p>\n<p>SSH (Secure Shell) protokol\u00fc ve uygulamalar\u0131 hakk\u0131nda en do\u011fru ve g\u00fcncel bilgilere ula\u015fman\u0131n en g\u00fcvenilir yolu, resmi dok\u00fcmantasyonlara ba\u015fvurmakt\u0131r. Dok\u00fcmantasyonlar, SSH&#8217;nin nas\u0131l \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131, yap\u0131land\u0131rma se\u00e7eneklerini, g\u00fcvenlik \u00f6nerilerini ve sorun giderme ipu\u00e7lar\u0131n\u0131 detayl\u0131 bir \u015fekilde a\u00e7\u0131klar.<\/p>\n<p><strong>1.1 OpenSSH Resmi Dok\u00fcmantasyonu<\/strong><\/p>\n<p>OpenSSH, en yayg\u0131n kullan\u0131lan SSH uygulamalar\u0131ndan biridir ve bir\u00e7ok Linux da\u011f\u0131t\u0131m\u0131nda varsay\u0131lan olarak bulunur. OpenSSH&#8217;nin resmi dok\u00fcmantasyonu, SSH hakk\u0131nda kapsaml\u0131 bilgiler sunar.<\/p>\n<ul>\n<li><strong>OpenSSH Web Sitesi:<\/strong> <a href=\"https:\/\/www.openssh.com\/\">https:\/\/www.openssh.com\/<\/a>OpenSSH web sitesi, OpenSSH hakk\u0131nda genel bilgiler, son s\u00fcr\u00fcm duyurular\u0131, g\u00fcvenlik g\u00fcncellemeleri ve dok\u00fcmantasyon ba\u011flant\u0131lar\u0131 i\u00e7erir.<\/li>\n<li><strong>OpenSSH Manual (Man) Sayfalar\u0131:<\/strong>OpenSSH&#8217;nin bir\u00e7ok bile\u015feni (\u00f6rne\u011fin, <code>ssh<\/code>, <code>sshd<\/code>, <code>ssh-keygen<\/code>, <code>ssh-copy-id<\/code>) i\u00e7in ayr\u0131nt\u0131l\u0131 man sayfalar\u0131 bulunur. Man sayfalar\u0131na eri\u015fmek i\u00e7in komut sat\u0131r\u0131nda a\u015fa\u011f\u0131daki komutlar\u0131 kullanabilirsiniz:\n<pre><code class=\"lang-bash\">man ssh       <span class=\"hljs-comment\"># SSH istemci komutu hakk\u0131nda bilgi<\/span>\r\nman sshd      <span class=\"hljs-comment\"># SSH sunucu komutu hakk\u0131nda bilgi<\/span>\r\nman ssh-keygen <span class=\"hljs-comment\"># SSH anahtar olu\u015fturma komutu hakk\u0131nda bilgi<\/span>\r\nman ssh-<span class=\"hljs-keyword\">copy<\/span>-<span class=\"hljs-built_in\">id<\/span> <span class=\"hljs-comment\"># SSH genel anahtar\u0131n\u0131 sunucuya kopyalama komutu hakk\u0131nda bilgi<\/span>\r\n<\/code><\/pre>\n<p>Man sayfalar\u0131, komutlar\u0131n kullan\u0131m\u0131n\u0131, se\u00e7eneklerini, yap\u0131land\u0131rma dosyalar\u0131n\u0131 ve di\u011fer ilgili bilgileri detayl\u0131 bir \u015fekilde a\u00e7\u0131klar.<\/li>\n<li><strong>OpenSSH README Dosyalar\u0131:<\/strong>OpenSSH kaynak kodunu indirdi\u011finizde, \u00e7e\u015fitli README dosyalar\u0131 bulabilirsiniz. Bu dosyalar, OpenSSH&#8217;nin kurulumu, yap\u0131land\u0131r\u0131lmas\u0131, g\u00fcvenlik \u00f6nerileri ve sorun giderme ipu\u00e7lar\u0131 hakk\u0131nda bilgiler i\u00e7erir.<\/li>\n<\/ul>\n<p><strong>1.2 Linux Da\u011f\u0131t\u0131m\u0131na \u00d6zel SSH Dok\u00fcmanlar\u0131<\/strong><\/p>\n<p>Linux da\u011f\u0131t\u0131mlar\u0131, OpenSSH&#8217;yi kendi sistemlerine entegre ederken baz\u0131 de\u011fi\u015fiklikler yapabilir veya ek yap\u0131land\u0131rma se\u00e7enekleri sunabilir. Bu nedenle, kulland\u0131\u011f\u0131n\u0131z Linux da\u011f\u0131t\u0131m\u0131na \u00f6zel SSH dok\u00fcmanlar\u0131na ba\u015fvurmak faydal\u0131 olabilir.<\/p>\n<ul>\n<li><strong>Ubuntu SSH Dok\u00fcmanlar\u0131:<\/strong> <a href=\"https:\/\/help.ubuntu.com\/community\/SSH\">https:\/\/help.ubuntu.com\/community\/SSH<\/a>Ubuntu SSH dok\u00fcmanlar\u0131, Ubuntu&#8217;da SSH&#8217;nin nas\u0131l kurulaca\u011f\u0131n\u0131, yap\u0131land\u0131r\u0131laca\u011f\u0131n\u0131, g\u00fcvenli hale getirilece\u011fini ve sorun giderilece\u011fini a\u00e7\u0131klar.<\/li>\n<li><strong>Debian SSH Dok\u00fcmanlar\u0131:<\/strong> <a href=\"https:\/\/wiki.debian.org\/SSH\">https:\/\/wiki.debian.org\/SSH<\/a>Debian SSH dok\u00fcmanlar\u0131, Debian&#8217;da SSH&#8217;nin nas\u0131l kurulaca\u011f\u0131n\u0131, yap\u0131land\u0131r\u0131laca\u011f\u0131n\u0131, g\u00fcvenli hale getirilece\u011fini ve sorun giderilece\u011fini a\u00e7\u0131klar.<\/li>\n<li><strong>CentOS SSH Dok\u00fcmanlar\u0131:<\/strong>CentOS, Red Hat Enterprise Linux (RHEL) tabanl\u0131 bir Linux da\u011f\u0131t\u0131m\u0131d\u0131r. RHEL SSH dok\u00fcmanlar\u0131, CentOS i\u00e7in de ge\u00e7erlidir. Red Hat Customer Portal&#8217;dan RHEL dok\u00fcmanlar\u0131na eri\u015febilirsiniz.<\/li>\n<li><strong>Arch Linux SSH Dok\u00fcmanlar\u0131:<\/strong> <a href=\"https:\/\/wiki.archlinux.org\/title\/SSH\">https:\/\/wiki.archlinux.org\/title\/SSH<\/a>Arch Linux SSH dok\u00fcmanlar\u0131, Arch Linux&#8217;ta SSH&#8217;nin nas\u0131l kurulaca\u011f\u0131n\u0131, yap\u0131land\u0131r\u0131laca\u011f\u0131n\u0131, g\u00fcvenli hale getirilece\u011fini ve sorun giderilece\u011fini a\u00e7\u0131klar. Arch Linux Wiki, genellikle di\u011fer Linux da\u011f\u0131t\u0131mlar\u0131 i\u00e7in de faydal\u0131 bilgiler i\u00e7erir.<\/li>\n<\/ul>\n<p><strong>1.3 Di\u011fer SSH Uygulamalar\u0131n\u0131n Dok\u00fcmantasyonu<\/strong><\/p>\n<p>OpenSSH d\u0131\u015f\u0131nda, di\u011fer SSH uygulamalar\u0131 (\u00f6rne\u011fin, PuTTY, Bitvise SSH Client) da kendi dok\u00fcmantasyonlar\u0131na sahiptir. Bu dok\u00fcmantasyonlar, ilgili uygulaman\u0131n kullan\u0131m\u0131n\u0131, yap\u0131land\u0131rma se\u00e7eneklerini ve sorun giderme ipu\u00e7lar\u0131n\u0131 a\u00e7\u0131klar.<\/p>\n<ul>\n<li><strong>PuTTY Dok\u00fcmantasyonu:<\/strong> <a href=\"https:\/\/www.chiark.greenend.org.uk\/~sgtatham\/putty\/docs.html\">https:\/\/www.chiark.greenend.org.uk\/~sgtatham\/putty\/docs.html<\/a>PuTTY dok\u00fcmantasyonu, PuTTY&#8217;nin kullan\u0131m\u0131, yap\u0131land\u0131r\u0131lmas\u0131, ba\u011flant\u0131 sorunlar\u0131n\u0131n giderilmesi ve di\u011fer ilgili konular hakk\u0131nda bilgi i\u00e7erir.<\/li>\n<li><strong>Bitvise SSH Client Dok\u00fcmantasyonu:<\/strong> <a href=\"https:\/\/www.bitvise.com\/ssh-client-documentation\">https:\/\/www.bitvise.com\/ssh-client-documentation<\/a>Bitvise SSH Client dok\u00fcmantasyonu, Bitvise SSH Client&#8217;\u0131n kullan\u0131m\u0131, yap\u0131land\u0131r\u0131lmas\u0131, ba\u011flant\u0131 sorunlar\u0131n\u0131n giderilmesi ve di\u011fer ilgili konular hakk\u0131nda bilgi i\u00e7erir.<\/li>\n<\/ul>\n<p><strong>2. Online Forumlar ve Topluluklardan Yard\u0131m Alma<\/strong><\/p>\n<p>SSH ba\u011flant\u0131 problemleriyle kar\u015f\u0131la\u015ft\u0131\u011f\u0131n\u0131zda, online forumlar ve topluluklar, deneyimli kullan\u0131c\u0131lardan ve uzmanlardan yard\u0131m alabilece\u011finiz de\u011ferli kaynaklard\u0131r. Forumlarda ve topluluklarda soru sorabilir, sorunlar\u0131n\u0131z\u0131 payla\u015fabilir ve \u00e7\u00f6z\u00fcm \u00f6nerileri alabilirsiniz.<\/p>\n<p><strong>2.1 Stack Overflow<\/strong><\/p>\n<p>Stack Overflow, programlama, sistem y\u00f6netimi ve di\u011fer teknik konularda soru sormak ve cevaplamak i\u00e7in pop\u00fcler bir platformdur. SSH ba\u011flant\u0131 problemleriyle ilgili sorular\u0131n\u0131z\u0131 Stack Overflow&#8217;da sorarak, deneyimli kullan\u0131c\u0131lardan ve uzmanlardan yard\u0131m alabilirsiniz.<\/p>\n<ul>\n<li><strong>Stack Overflow&#8217;da SSH ile \u0130lgili Sorular:<\/strong> <a href=\"https:\/\/stackoverflow.com\/questions\/tagged\/ssh\">https:\/\/stackoverflow.com\/questions\/tagged\/ssh<\/a>Stack Overflow&#8217;da SSH etiketiyle i\u015faretlenmi\u015f sorular\u0131 inceleyerek, benzer sorunlarla kar\u015f\u0131la\u015fm\u0131\u015f olan di\u011fer kullan\u0131c\u0131lar\u0131n deneyimlerinden ve \u00e7\u00f6z\u00fcm \u00f6nerilerinden faydalanabilirsiniz.<\/li>\n<\/ul>\n<p><strong>2.2 Server Fault<\/strong><\/p>\n<p>Server Fault, sunucu y\u00f6netimi, a\u011f yap\u0131land\u0131rmas\u0131 ve di\u011fer sistem y\u00f6netimi konular\u0131nda soru sormak ve cevaplamak i\u00e7in bir platformdur. SSH ba\u011flant\u0131 problemleriyle ilgili sorular\u0131n\u0131z\u0131 Server Fault&#8217;da sorarak, sistem y\u00f6neticilerinden ve uzmanlardan yard\u0131m alabilirsiniz.<\/p>\n<ul>\n<li><strong>Server Fault&#8217;da SSH ile \u0130lgili Sorular:<\/strong> <a href=\"https:\/\/serverfault.com\/questions\/tagged\/ssh\">https:\/\/serverfault.com\/questions\/tagged\/ssh<\/a>Server Fault&#8217;da SSH etiketiyle i\u015faretlenmi\u015f sorular\u0131 inceleyerek, benzer sorunlarla kar\u015f\u0131la\u015fm\u0131\u015f olan di\u011fer kullan\u0131c\u0131lar\u0131n deneyimlerinden ve \u00e7\u00f6z\u00fcm \u00f6nerilerinden faydalanabilirsiniz.<\/li>\n<\/ul>\n<p><strong>2.3 Linux Kullan\u0131c\u0131 Gruplar\u0131 ve Forumlar\u0131<\/strong><\/p>\n<p>Linux kullan\u0131c\u0131 gruplar\u0131 ve forumlar\u0131, Linux sistemleri hakk\u0131nda bilgi payla\u015fmak, soru sormak ve yard\u0131m almak i\u00e7in harika kaynaklard\u0131r. Kulland\u0131\u011f\u0131n\u0131z Linux da\u011f\u0131t\u0131m\u0131na \u00f6zel bir kullan\u0131c\u0131 grubu veya forumu bularak, SSH ba\u011flant\u0131 problemleriyle ilgili sorular\u0131n\u0131z\u0131 sorabilir ve deneyimli kullan\u0131c\u0131lardan yard\u0131m alabilirsiniz.<\/p>\n<ul>\n<li><strong>Ubuntu Forums:<\/strong> <a href=\"https:\/\/ubuntuforums.org\/\">https:\/\/ubuntuforums.org\/<\/a><\/li>\n<li><strong>Debian User Forums:<\/strong> <a href=\"https:\/\/forums.debian.net\/\">https:\/\/forums.debian.net\/<\/a><\/li>\n<li><strong>CentOS Community Forums:<\/strong> <a href=\"https:\/\/forums.centos.org\/\">https:\/\/forums.centos.org\/<\/a><\/li>\n<li><strong>Arch Linux Forums:<\/strong> <a href=\"https:\/\/bbs.archlinux.org\/\">https:\/\/bbs.archlinux.org\/<\/a><\/li>\n<\/ul>\n<p><strong>2.4 Di\u011fer Online Forumlar ve Topluluklar<\/strong><\/p>\n<ul>\n<li><strong>Reddit:<\/strong> Reddit&#8217;te <code>\/r\/linuxadmin<\/code>, <code>\/r\/sysadmin<\/code> ve <code>\/r\/ssh<\/code> gibi subreddit&#8217;lerde SSH ile ilgili sorular sorabilir ve yard\u0131m alabilirsiniz.<\/li>\n<li><strong>Super User:<\/strong> Super User, bilgisayar kullan\u0131m\u0131, yaz\u0131l\u0131m ve donan\u0131m sorunlar\u0131 hakk\u0131nda soru sormak ve cevaplamak i\u00e7in bir platformdur. SSH ba\u011flant\u0131 problemleriyle ilgili sorular\u0131n\u0131z\u0131 Super User&#8217;da sorarak, deneyimli kullan\u0131c\u0131lardan yard\u0131m alabilirsiniz.<\/li>\n<\/ul>\n<p><strong>3. Profesyonel Destek Alma<\/strong><\/p>\n<p>SSH ba\u011flant\u0131 problemleriyle ilgili sorun giderme s\u00fcrecinde tak\u0131l\u0131p kald\u0131ysan\u0131z veya karma\u015f\u0131k bir ortamda \u00e7al\u0131\u015f\u0131yorsan\u0131z, profesyonel destek almay\u0131 d\u00fc\u015f\u00fcnebilirsiniz. Profesyonel destek, genellikle \u00fccretli bir hizmettir, ancak uzmanlar\u0131n yard\u0131m\u0131yla sorununuzu en k\u0131sa s\u00fcrede ve etkili bir \u015fekilde \u00e7\u00f6zmenize yard\u0131mc\u0131 olabilir.<\/p>\n<p><strong>3.1 Sistem Y\u00f6netimi \u015eirketleri<\/strong><\/p>\n<p>Sistem y\u00f6netimi \u015firketleri, sunucu y\u00f6netimi, a\u011f yap\u0131land\u0131rmas\u0131, g\u00fcvenlik ve di\u011fer IT hizmetleri sunar. SSH ba\u011flant\u0131 problemleriyle ilgili sorunlar\u0131n\u0131z\u0131 \u00e7\u00f6zmek i\u00e7in bir sistem y\u00f6netimi \u015firketinden destek alabilirsiniz.<\/p>\n<p><strong>3.2 Bulut Sa\u011flay\u0131c\u0131lar\u0131<\/strong><\/p>\n<p>Bulut sa\u011flay\u0131c\u0131lar\u0131 (\u00f6rne\u011fin, AWS, Azure, GCP), bulut kaynaklar\u0131n\u0131n y\u00f6netimi ve sorun giderme konusunda destek hizmetleri sunar. SSH ba\u011flant\u0131 problemleriyle ilgili sorunlar\u0131n\u0131z\u0131 \u00e7\u00f6zmek i\u00e7in bulut sa\u011flay\u0131c\u0131n\u0131zdan destek alabilirsiniz.<\/p>\n<p><strong>3.3 Ba\u011f\u0131ms\u0131z Dan\u0131\u015fmanlar<\/strong><\/p>\n<p>Ba\u011f\u0131ms\u0131z dan\u0131\u015fmanlar, belirli bir alanda uzmanla\u015fm\u0131\u015f ve \u015firketlere veya bireylere dan\u0131\u015fmanl\u0131k hizmeti sunan ki\u015filerdir. SSH ba\u011flant\u0131 problemleriyle ilgili sorunlar\u0131n\u0131z\u0131 \u00e7\u00f6zmek i\u00e7in bir ba\u011f\u0131ms\u0131z dan\u0131\u015fmandan destek alabilirsiniz.<\/p>\n<p><strong>4. Soru Sorarken Dikkat Edilmesi Gerekenler<\/strong><\/p>\n<p>Online forumlarda veya topluluklarda soru sorarken, sorununuzu en iyi \u015fekilde a\u00e7\u0131klamak ve do\u011fru cevaplar\u0131 almak i\u00e7in dikkat etmeniz gereken baz\u0131 noktalar vard\u0131r:<\/p>\n<ul>\n<li><strong>Detayl\u0131 A\u00e7\u0131klama:<\/strong> Sorununuzu m\u00fcmk\u00fcn oldu\u011funca detayl\u0131 bir \u015fekilde a\u00e7\u0131klay\u0131n. Hangi ad\u0131mlar\u0131 denedi\u011finizi, hangi hata mesajlar\u0131n\u0131 ald\u0131\u011f\u0131n\u0131z\u0131 ve hangi sonu\u00e7lara ula\u015ft\u0131\u011f\u0131n\u0131z\u0131 belirtin.<\/li>\n<li><strong>\u0130lgili Bilgileri Sa\u011flama:<\/strong> \u0130\u015fletim sistemi, SSH s\u00fcr\u00fcm\u00fc, g\u00fcvenlik duvar\u0131 yap\u0131land\u0131rmas\u0131, a\u011f topolojisi ve di\u011fer ilgili bilgileri sa\u011flay\u0131n.<\/li>\n<li><strong>Do\u011fru Etiketleri Kullanma:<\/strong> Soru sordu\u011funuz platformda, sorununuzu do\u011fru \u015fekilde etiketleyin (\u00f6rne\u011fin, SSH, Linux, networking, security). Bu, sorununuzu do\u011fru ki\u015filere ula\u015fmas\u0131na yard\u0131mc\u0131 olacakt\u0131r.<\/li>\n<li><strong>Anla\u015f\u0131l\u0131r Dil Kullanma:<\/strong> Teknik terimleri do\u011fru ve anla\u015f\u0131l\u0131r bir \u015fekilde kullan\u0131n. Karma\u015f\u0131k c\u00fcmlelerden ka\u00e7\u0131n\u0131n ve sorunuzu net bir \u015fekilde ifade edin.<\/li>\n<li><strong>Sab\u0131rl\u0131 Olma:<\/strong> Cevap almak biraz zaman alabilir. Sab\u0131rl\u0131 olun ve sorunuzu d\u00fczenli olarak kontrol edin.<\/li>\n<li><strong>Te\u015fekk\u00fcr Etme:<\/strong> Yard\u0131m eden ki\u015filere te\u015fekk\u00fcr etmeyi unutmay\u0131n.<\/li>\n<\/ul>\n<p><strong>5. SSH G\u00fcvenli\u011fini Art\u0131rma \u0130pu\u00e7lar\u0131<\/strong><\/p>\n<p>SSH ba\u011flant\u0131 problemleriyle u\u011fra\u015f\u0131rken, SSH g\u00fcvenli\u011finizi art\u0131rmak da \u00f6nemlidir. G\u00fcvenli bir SSH yap\u0131land\u0131rmas\u0131, hem ba\u011flant\u0131 sorunlar\u0131n\u0131 \u00f6nlemeye yard\u0131mc\u0131 olur, hem de sunucunuzu yetkisiz eri\u015fime kar\u015f\u0131 korur.<\/p>\n<ul>\n<li><strong>G\u00fc\u00e7l\u00fc Parolalar Kullanma:<\/strong> Parola tabanl\u0131 kimlik do\u011frulama kullan\u0131yorsan\u0131z, g\u00fc\u00e7l\u00fc ve tahmin edilmesi zor parolalar kullan\u0131n.<\/li>\n<li><strong>Anahtar Tabanl\u0131 Kimlik Do\u011frulama Kullanma:<\/strong> Anahtar tabanl\u0131 kimlik do\u011frulama, paroladan daha g\u00fcvenli bir y\u00f6ntemdir. Anahtar tabanl\u0131 kimlik do\u011frulamay\u0131 tercih edin ve parolalar\u0131 devre d\u0131\u015f\u0131 b\u0131rak\u0131n.<\/li>\n<li><strong>SSH Portunu De\u011fi\u015ftirme:<\/strong> Varsay\u0131lan SSH portu olan 22&#8217;yi de\u011fi\u015ftirerek, otomatik sald\u0131r\u0131 giri\u015fimlerini azaltabilirsiniz. Ancak, portu de\u011fi\u015ftirirken g\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131z\u0131 da g\u00fcncellemeyi unutmay\u0131n.<\/li>\n<li><strong>Fail2ban Kullanma:<\/strong> Fail2ban, ba\u015far\u0131s\u0131z kimlik do\u011frulama giri\u015fimlerini tespit ederek, sald\u0131rganlar\u0131n IP adreslerini otomatik olarak engelleyen bir ara\u00e7t\u0131r.<\/li>\n<li><strong>\u0130ki Fakt\u00f6rl\u00fc Kimlik Do\u011frulama (2FA) Kullanma:<\/strong> \u0130ki fakt\u00f6rl\u00fc kimlik do\u011frulama, parolaya ek olarak bir do\u011frulama kodu gerektirerek, g\u00fcvenli\u011fi \u00f6nemli \u00f6l\u00e7\u00fcde art\u0131r\u0131r.<\/li>\n<li><strong>D\u00fczenli Olarak G\u00fcncelleme Yapma:<\/strong> SSH uygulaman\u0131z\u0131 ve i\u015fletim sisteminizi d\u00fczenli olarak g\u00fcncelleyerek, g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 kapat\u0131n.<\/li>\n<li><strong>Gereksiz \u00d6zellikleri Devre D\u0131\u015f\u0131 B\u0131rakma:<\/strong> GSSAPI kimlik do\u011frulamas\u0131 veya DNS \u00e7\u00f6z\u00fcmlemesi gibi gereksiz \u00f6zellikleri devre d\u0131\u015f\u0131 b\u0131rakarak, sald\u0131r\u0131 y\u00fczeyinizi azaltabilirsiniz.<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Kullanma:<\/strong> SSH trafi\u011fini yaln\u0131zca belirli IP adreslerinden veya a\u011flardan gelen ba\u011flant\u0131lara izin verecek \u015fekilde yap\u0131land\u0131r\u0131lm\u0131\u015f bir g\u00fcvenlik duvar\u0131 kullan\u0131n.<\/li>\n<\/ul>\n<p><strong>6. SSH Ba\u011flant\u0131lar\u0131n\u0131 S\u00fcrekli \u0130zleme ve Y\u00f6netme<\/strong><\/p>\n<p>SSH ba\u011flant\u0131lar\u0131n\u0131 s\u00fcrekli olarak izlemek ve y\u00f6netmek, potansiyel sorunlar\u0131 erken tespit etmenize ve g\u00fcvenlik ihlallerini \u00f6nlemenize yard\u0131mc\u0131 olabilir.<\/p>\n<ul>\n<li><strong>Log Analiz Ara\u00e7lar\u0131 Kullanma:<\/strong> Log analiz ara\u00e7lar\u0131, SSH sunucu loglar\u0131n\u0131 otomatik olarak analiz ederek, ola\u011fand\u0131\u015f\u0131\u6d3b\u52a8lar\u0131, hatalar\u0131 ve g\u00fcvenlik tehditlerini tespit etmenize yard\u0131mc\u0131 olabilir.<\/li>\n<li><strong>SSH \u0130zleme Ara\u00e7lar\u0131 Kullanma:<\/strong> SSH izleme ara\u00e7lar\u0131, SSH ba\u011flant\u0131lar\u0131n\u0131 ger\u00e7ek zamanl\u0131 olarak izleyerek, kimin ne zaman ba\u011fland\u0131\u011f\u0131n\u0131, hangi komutlar\u0131 \u00e7al\u0131\u015ft\u0131rd\u0131\u011f\u0131n\u0131 ve ne kadar veri aktard\u0131\u011f\u0131n\u0131 g\u00f6rmenizi sa\u011flar.<\/li>\n<li><strong>SSH Anahtarlar\u0131n\u0131 D\u00fczenli Olarak Y\u00f6netme:<\/strong> SSH anahtarlar\u0131n\u0131 d\u00fczenli olarak y\u00f6netmek, kullan\u0131lmayan veya tehlikeye girmi\u015f anahtarlar\u0131 iptal etmek ve yeni anahtarlar olu\u015fturmak, g\u00fcvenli\u011fi art\u0131rman\u0131za yard\u0131mc\u0131 olur.<\/li>\n<li><strong>Otomatik Uyar\u0131lar Kurma:<\/strong> Belirli olaylar (\u00f6rne\u011fin, ba\u015far\u0131s\u0131z kimlik do\u011frulama giri\u015fimleri, ola\u011fand\u0131\u015f\u0131 ba\u011flant\u0131\u6d3b\u52a8lar\u0131) ger\u00e7ekle\u015fti\u011finde otomatik uyar\u0131lar alarak, h\u0131zl\u0131 bir \u015fekilde m\u00fcdahale edebilirsiniz.<\/li>\n<\/ul>\n<p><strong>7. \u00d6rnek Olay \u0130ncelemeleri<\/strong><\/p>\n<p>A\u015fa\u011f\u0131da, SSH ba\u011flant\u0131 problemleriyle ilgili baz\u0131 \u00f6rnek olay incelemeleri ve \u00e7\u00f6z\u00fcm \u00f6nerileri bulunmaktad\u0131r:<\/p>\n<ul>\n<li><strong>Olay \u0130ncelemesi 1:<\/strong> Bir kullan\u0131c\u0131, AWS&#8217;deki bir EC2 \u00f6rne\u011fine ba\u011flanmaya \u00e7al\u0131\u015f\u0131r, ancak ba\u011flant\u0131 zaman a\u015f\u0131m\u0131na u\u011frar.\n<ul>\n<li><strong>Sorun:<\/strong> G\u00fcvenlik grubu ayarlar\u0131nda SSH trafi\u011fine izin veren bir kural eksiktir.<\/li>\n<li><strong>\u00c7\u00f6z\u00fcm:<\/strong> AWS Management Console&#8217;da EC2 &gt; G\u00fcvenlik Gruplar\u0131&#8217;na gidin. \u0130lgili g\u00fcvenlik grubunu se\u00e7in ve &#8220;Gelen Kurallar&#8221; sekmesinde, 22 numaral\u0131 port \u00fczerinden TCP trafi\u011fine izin veren bir kural ekleyin.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Olay \u0130ncelemesi 2:<\/strong> Bir sistem y\u00f6neticisi, sunucusuna SSH ile ba\u011flan\u0131r, ancak ba\u011flant\u0131 s\u00fcrekli olarak kesintiye u\u011frar.\n<ul>\n<li><strong>Sorun:<\/strong> TCP Keep-Alive ayarlar\u0131 etkin de\u011fildir.<\/li>\n<li><strong>\u00c7\u00f6z\u00fcm:<\/strong> Hem istemci hem de sunucu taraf\u0131nda TCP Keep-Alive ayarlar\u0131n\u0131 yap\u0131land\u0131r\u0131n. <code>~\/.ssh\/config<\/code> dosyas\u0131na <code>ServerAliveInterval<\/code> ve <code>ServerAliveCountMax<\/code> parametrelerini ekleyin ve <code>\/etc\/ssh\/sshd_config<\/code> dosyas\u0131na <code>ClientAliveInterval<\/code>, <code>ClientAliveCountMax<\/code> ve <code>TCPKeepAlive<\/code> parametrelerini ekleyin.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Olay \u0130ncelemesi 3:<\/strong> Bir geli\u015ftirici, yerel makinesindeki bir web taray\u0131c\u0131s\u0131 arac\u0131l\u0131\u011f\u0131yla uzak sunucudaki bir web uygulamas\u0131na eri\u015fmek ister, ancak ba\u011flant\u0131 reddedilir.\n<ul>\n<li><strong>Sorun:<\/strong> Port y\u00f6nlendirme do\u011fru yap\u0131land\u0131r\u0131lmam\u0131\u015ft\u0131r veya port \u00e7ak\u0131\u015fmas\u0131 vard\u0131r.<\/li>\n<li><strong>\u00c7\u00f6z\u00fcm:<\/strong> SSH komutundaki port numaralar\u0131n\u0131 kontrol edin ve do\u011fru oldu\u011fundan emin olun. <code>netstat -tulnp<\/code> komutuyla port \u00e7ak\u0131\u015fmas\u0131 olup olmad\u0131\u011f\u0131n\u0131 kontrol edin ve gerekirse port numaras\u0131n\u0131 de\u011fi\u015ftirin.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr<\/strong> sorusuna cevap ararken, \u00e7e\u015fitli kaynaklara ba\u015fvurmak ve yard\u0131m almak \u00f6nemlidir. Resmi dok\u00fcmantasyonlar, online forumlar, topluluklar ve profesyonel destek, sorun giderme s\u00fcrecinde size rehberlik edebilir. Soru sorarken dikkatli olmak, g\u00fcvenli\u011fi art\u0131rmak ve ba\u011flant\u0131lar\u0131 s\u00fcrekli olarak izlemek, SSH deneyiminizi iyile\u015ftirmenize ve sorunlar\u0131 \u00f6nlemenize yard\u0131mc\u0131 olacakt\u0131r. Bu b\u00f6l\u00fcmde sunulan ek kaynaklar ve yard\u0131m alma y\u00f6ntemleri, SSH ba\u011flant\u0131 problemleriyle kar\u015f\u0131la\u015ft\u0131\u011f\u0131n\u0131zda size yol g\u00f6sterecek ve sorununuzu en k\u0131sa s\u00fcrede \u00e7\u00f6zmenize yard\u0131mc\u0131 olacakt\u0131r.<\/p>\n<h2 id=\"8-sonu-ssh-ba-lant-problemlerini-nleme-ve-s-rekli-i-zleme\"><span class=\"ez-toc-section\" id=\"8_Sonuc_SSH_Baglanti_Problemlerini_Onleme_ve_Surekli_Izleme\"><\/span>8. Sonu\u00e7: SSH Ba\u011flant\u0131 Problemlerini \u00d6nleme ve S\u00fcrekli \u0130zleme<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>SSH ba\u011flant\u0131 problemleriyle kar\u015f\u0131la\u015fmak, sistem y\u00f6neticileri, geli\u015ftiriciler ve genel olarak sunucularla etkile\u015fimde bulunan herkes i\u00e7in sinir bozucu ve zaman kayb\u0131na neden olabilecek bir deneyimdir. Bu rehber boyunca, &#8220;SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr&#8221; sorusuna kapsaml\u0131 bir yan\u0131t sunmak i\u00e7in \u00e7e\u015fitli nedenleri, \u00e7\u00f6z\u00fcmleri ve ara\u00e7lar\u0131 inceledik. Ancak, en iyi \u00e7\u00f6z\u00fcm her zaman sorunu en ba\u015ftan \u00f6nlemektir. Bu b\u00f6l\u00fcmde, SSH ba\u011flant\u0131 problemlerini en aza indirmek, g\u00fcvenli\u011fi art\u0131rmak ve sistemlerinizi s\u00fcrekli olarak izlemek i\u00e7in uygulayabilece\u011finiz stratejileri ve en iyi uygulamalar\u0131 ele alaca\u011f\u0131z. Amac\u0131m\u0131z, proaktif bir yakla\u015f\u0131mla SSH ba\u011flant\u0131 sorunlar\u0131n\u0131 \u00f6nlemenize ve kar\u015f\u0131la\u015ft\u0131\u011f\u0131n\u0131zda h\u0131zl\u0131 ve etkili bir \u015fekilde m\u00fcdahale etmenize yard\u0131mc\u0131 olmakt\u0131r.<\/p>\n<p><strong>SSH G\u00fcvenli\u011fini Art\u0131rma \u0130pu\u00e7lar\u0131<\/strong><\/p>\n<p>SSH g\u00fcvenli\u011fi, yaln\u0131zca ba\u011flant\u0131 problemlerini \u00f6nlemekle kalmaz, ayn\u0131 zamanda sunucular\u0131n\u0131z\u0131 yetkisiz eri\u015fime, veri ihlallerine ve di\u011fer siber tehditlere kar\u015f\u0131 da korur. G\u00fcvenli bir SSH yap\u0131land\u0131rmas\u0131, sistemlerinizin b\u00fct\u00fcnl\u00fc\u011f\u00fcn\u00fc ve gizlili\u011fini sa\u011flamak i\u00e7in kritik \u00f6neme sahiptir. &#8220;SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr&#8221; sorusunu ele al\u0131rken, g\u00fcvenlik \u00f6nlemlerini de g\u00f6z \u00f6n\u00fcnde bulundurmak \u00f6nemlidir.<\/p>\n<ul>\n<li><strong>G\u00fc\u00e7l\u00fc Parolalar Kullanma:<\/strong>Parola tabanl\u0131 kimlik do\u011frulama kullan\u0131yorsan\u0131z, g\u00fc\u00e7l\u00fc ve tahmin edilmesi zor parolalar kullanmak esast\u0131r. Zay\u0131f parolalar, brute-force sald\u0131r\u0131lar\u0131na kar\u015f\u0131 savunmas\u0131zd\u0131r ve yetkisiz eri\u015fime yol a\u00e7abilir.\n<ul>\n<li><strong>Parola Olu\u015fturma \u0130lkeleri:<\/strong>\n<ul>\n<li>En az 12 karakter uzunlu\u011funda olmal\u0131d\u0131r.<\/li>\n<li>B\u00fcy\u00fck harfler, k\u00fc\u00e7\u00fck harfler, rakamlar ve semboller i\u00e7ermelidir.<\/li>\n<li>Ki\u015fisel bilgiler (ad, do\u011fum tarihi, evcil hayvan ad\u0131 vb.) i\u00e7ermemelidir.<\/li>\n<li>S\u00f6zl\u00fck kelimeleri veya yayg\u0131n kullan\u0131lan ifadeler i\u00e7ermemelidir.<\/li>\n<li>Farkl\u0131 hesaplar i\u00e7in ayn\u0131 parola kullan\u0131lmamal\u0131d\u0131r.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Parola Y\u00f6netimi Ara\u00e7lar\u0131:<\/strong>\n<ul>\n<li>Parolalar\u0131 g\u00fcvenli bir \u015fekilde saklamak ve y\u00f6netmek i\u00e7in parola y\u00f6neticisi ara\u00e7lar\u0131 (\u00f6rne\u011fin, LastPass, 1Password, Bitwarden) kullan\u0131n.<\/li>\n<li>Parola y\u00f6neticisi ara\u00e7lar\u0131, g\u00fc\u00e7l\u00fc ve benzersiz parolalar olu\u015fturman\u0131za ve bunlar\u0131 hat\u0131rlaman\u0131za yard\u0131mc\u0131 olur.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Parola Politikalar\u0131:<\/strong>\n<ul>\n<li>Parola politikalar\u0131 uygulayarak, kullan\u0131c\u0131lar\u0131n g\u00fc\u00e7l\u00fc parolalar kullanmas\u0131n\u0131 ve d\u00fczenli olarak de\u011fi\u015ftirmesini sa\u011flay\u0131n.<\/li>\n<li>Parola politikalar\u0131, parola uzunlu\u011fu, karma\u015f\u0131kl\u0131\u011f\u0131, ge\u00e7mi\u015fi ve ge\u00e7erlilik s\u00fcresi gibi kriterleri belirleyebilir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>Anahtar Tabanl\u0131 Kimlik Do\u011frulamay\u0131 Tercih Etme:<\/strong>Anahtar tabanl\u0131 kimlik do\u011frulama, paroladan \u00e7ok daha g\u00fcvenli bir y\u00f6ntemdir. Anahtar tabanl\u0131 kimlik do\u011frulama, \u00f6zel anahtar\u0131n\u0131z\u0131 kullanarak sunucuya g\u00fcvenli bir \u015fekilde ba\u011flanman\u0131z\u0131 sa\u011flar ve parolalar\u0131n \u00e7al\u0131nmas\u0131 veya tahmin edilmesi riskini ortadan kald\u0131r\u0131r.\n<ul>\n<li><strong>Anahtar \u00c7ifti Olu\u015fturma:<\/strong>\n<ul>\n<li><code>ssh-keygen<\/code> komutunu kullanarak bir anahtar \u00e7ifti (\u00f6zel anahtar ve genel anahtar) olu\u015fturun.<\/li>\n<li>G\u00fc\u00e7l\u00fc bir \u015fifreleme algoritmas\u0131 (\u00f6rne\u011fin, RSA, ECDSA, Ed25519) ve g\u00fcvenli bir anahtar uzunlu\u011fu (\u00f6rne\u011fin, RSA i\u00e7in 4096 bit) kullan\u0131n.<\/li>\n<li>\u00d6zel anahtar\u0131n\u0131z\u0131 g\u00fcvenli bir yerde saklay\u0131n ve yetkisiz eri\u015fime kar\u015f\u0131 koruyun.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Genel Anahtar\u0131 Sunucuya Kopyalama:<\/strong>\n<ul>\n<li><code>ssh-copy-id<\/code> komutunu kullanarak genel anahtar\u0131n\u0131z\u0131 sunucudaki <code>authorized_keys<\/code> dosyas\u0131na kopyalay\u0131n.<\/li>\n<li>Genel anahtar\u0131n\u0131z\u0131 manuel olarak kopyal\u0131yorsan\u0131z, do\u011fru formatta oldu\u011fundan ve fazladan bo\u015fluk veya sat\u0131r sonu karakteri i\u00e7ermedi\u011finden emin olun.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Parola Tabanl\u0131 Kimlik Do\u011frulamay\u0131 Devre D\u0131\u015f\u0131 B\u0131rakma:<\/strong>\n<ul>\n<li><code>sshd_config<\/code> dosyas\u0131nda <code>PasswordAuthentication no<\/code> olarak ayarlayarak parola tabanl\u0131 kimlik do\u011frulamay\u0131 devre d\u0131\u015f\u0131 b\u0131rak\u0131n.<\/li>\n<li>Bu, sunucunuzu brute-force sald\u0131r\u0131lar\u0131na kar\u015f\u0131 \u00f6nemli \u00f6l\u00e7\u00fcde g\u00fc\u00e7lendirecektir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>SSH Portunu De\u011fi\u015ftirme:<\/strong>Varsay\u0131lan SSH portu olan 22, otomatik sald\u0131r\u0131 giri\u015fimlerinin hedefi olabilir. SSH portunu de\u011fi\u015ftirerek, bu t\u00fcr sald\u0131r\u0131lar\u0131 azaltabilirsiniz.\n<ul>\n<li><strong><code>sshd_config<\/code> Dosyas\u0131n\u0131 D\u00fczenleme:<\/strong>\n<ul>\n<li><code>sshd_config<\/code> dosyas\u0131nda <code>Port<\/code> parametresini de\u011fi\u015ftirin (\u00f6rne\u011fin, <code>Port 2222<\/code>).<\/li>\n<li>1024&#8217;ten b\u00fcy\u00fck ve kullan\u0131lmayan bir port numaras\u0131 se\u00e7in.<\/li>\n<\/ul>\n<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Ayarlar\u0131n\u0131 G\u00fcncelleme:<\/strong>\n<ul>\n<li>Yeni port numaras\u0131na izin vermek i\u00e7in g\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131z\u0131 g\u00fcncelleyin.<\/li>\n<li>UFW (Uncomplicated Firewall), iptables veya firewalld gibi ara\u00e7lar\u0131 kullanarak g\u00fcvenlik duvar\u0131 kurallar\u0131n\u0131 yap\u0131land\u0131r\u0131n.<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u0130stemci Taraf\u0131nda Portu Belirtme:<\/strong>\n<ul>\n<li>SSH ba\u011flant\u0131s\u0131 kurarken <code>-p<\/code> parametresi ile port numaras\u0131n\u0131 belirtin (\u00f6rne\u011fin, <code>ssh -p 2222 kullanici@example.com<\/code>).<\/li>\n<li><code>~\/.ssh\/config<\/code> dosyas\u0131nda <code>Port<\/code> parametresini kullanarak, belirli sunucular i\u00e7in farkl\u0131 port numaralar\u0131 tan\u0131mlayabilirsiniz.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>Fail2ban Gibi Ara\u00e7lar Kullanarak Brute-Force Sald\u0131r\u0131lar\u0131n\u0131 Engelleme:<\/strong>Fail2ban, ba\u015far\u0131s\u0131z kimlik do\u011frulama giri\u015fimlerini tespit ederek, sald\u0131rganlar\u0131n IP adreslerini otomatik olarak engelleyen bir ara\u00e7t\u0131r. Fail2ban, sunucunuzu brute-force sald\u0131r\u0131lar\u0131na kar\u015f\u0131 korumak i\u00e7in etkili bir \u00e7\u00f6z\u00fcmd\u00fcr.\n<ul>\n<li><strong>Fail2ban Kurulumu ve Yap\u0131land\u0131rmas\u0131:<\/strong>\n<ul>\n<li>Fail2ban&#8217;\u0131 kurmak i\u00e7in i\u015fletim sisteminize uygun paket y\u00f6netim arac\u0131n\u0131 kullan\u0131n (\u00f6rne\u011fin, <code>apt-get install fail2ban<\/code>, <code>yum install fail2ban<\/code>).<\/li>\n<li><code>\/etc\/fail2ban\/jail.conf<\/code> veya <code>\/etc\/fail2ban\/jail.local<\/code> dosyalar\u0131n\u0131 d\u00fczenleyerek Fail2ban&#8217;\u0131 yap\u0131land\u0131r\u0131n.<\/li>\n<li>SSH i\u00e7in bir &#8220;jail&#8221; olu\u015fturun ve ba\u015far\u0131s\u0131z kimlik do\u011frulama giri\u015fimlerini izlemek i\u00e7in filtreler tan\u0131mlay\u0131n.<\/li>\n<li>Engelleme s\u00fcresini, deneme say\u0131s\u0131n\u0131 ve di\u011fer parametreleri ayarlay\u0131n.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Fail2ban Loglar\u0131n\u0131 \u0130zleme:<\/strong>\n<ul>\n<li>Fail2ban loglar\u0131n\u0131 d\u00fczenli olarak izleyerek, sald\u0131r\u0131 giri\u015fimlerini ve engellenen IP adreslerini kontrol edin.<\/li>\n<li>Fail2ban, loglar\u0131 <code>\/var\/log\/fail2ban.log<\/code> dosyas\u0131na kaydeder.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u0130ki Fakt\u00f6rl\u00fc Kimlik Do\u011frulama (2FA) Kullanma:<\/strong>\u0130ki fakt\u00f6rl\u00fc kimlik do\u011frulama (2FA), parolaya ek olarak bir do\u011frulama kodu gerektirerek, g\u00fcvenli\u011fi \u00f6nemli \u00f6l\u00e7\u00fcde art\u0131r\u0131r. 2FA, parola tabanl\u0131 kimlik do\u011frulama kullan\u0131yorsan\u0131z veya anahtar tabanl\u0131 kimlik do\u011frulaman\u0131n yetersiz kald\u0131\u011f\u0131 durumlarda ek bir g\u00fcvenlik katman\u0131 sa\u011flar.\n<ul>\n<li><strong>2FA Mod\u00fcllerini Kurulumu ve Yap\u0131land\u0131rmas\u0131:<\/strong>\n<ul>\n<li>Google Authenticator, Authy veya FreeOTP gibi 2FA mod\u00fcllerini kurun.<\/li>\n<li>PAM (Pluggable Authentication Modules) yap\u0131land\u0131rma dosyalar\u0131n\u0131 (<code>\/etc\/pam.d\/sshd<\/code>) d\u00fczenleyerek, 2FA&#8217;y\u0131 SSH i\u00e7in etkinle\u015ftirin.<\/li>\n<li>Kullan\u0131c\u0131lar\u0131n 2FA&#8217;y\u0131 etkinle\u015ftirmesi ve do\u011frulama kodlar\u0131n\u0131 olu\u015fturmas\u0131 i\u00e7in talimatlar sa\u011flay\u0131n.<\/li>\n<\/ul>\n<\/li>\n<li><strong>2FA Yedekleme Y\u00f6ntemleri:<\/strong>\n<ul>\n<li>2FA cihaz\u0131n\u0131z\u0131 kaybetti\u011finiz veya eri\u015femedi\u011finiz durumlarda kullanabilece\u011finiz yedekleme y\u00f6ntemleri (\u00f6rne\u011fin, yedek kodlar, SMS do\u011frulama) ayarlay\u0131n.<\/li>\n<li>Yedekleme y\u00f6ntemlerini g\u00fcvenli bir yerde saklay\u0131n ve gerekti\u011finde nas\u0131l kullan\u0131laca\u011f\u0131n\u0131 bildi\u011finizden emin olun.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>D\u00fczenli Olarak G\u00fcncelleme Yapma:<\/strong>SSH uygulaman\u0131z\u0131 ve i\u015fletim sisteminizi d\u00fczenli olarak g\u00fcncelleyerek, g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 kapat\u0131n ve en son g\u00fcvenlik \u00f6zelliklerinden yararlan\u0131n.\n<ul>\n<li><strong>Otomatik G\u00fcncelleme Ayarlar\u0131:<\/strong>\n<ul>\n<li>Otomatik g\u00fcvenlik g\u00fcncellemelerini etkinle\u015ftirerek, sisteminizin en son g\u00fcvenlik yamalar\u0131yla g\u00fcncel kalmas\u0131n\u0131 sa\u011flay\u0131n.<\/li>\n<li>Otomatik g\u00fcncellemeler, g\u00fcvenlik a\u00e7\u0131klar\u0131n\u0131 kapatmak ve sald\u0131r\u0131lar\u0131 \u00f6nlemek i\u00e7in \u00f6nemlidir.<\/li>\n<\/ul>\n<\/li>\n<li><strong>G\u00fcncelleme Testleri:<\/strong>\n<ul>\n<li>G\u00fcncellemeleri canl\u0131 ortama uygulamadan \u00f6nce test ortam\u0131nda test ederek, olas\u0131 uyumluluk sorunlar\u0131n\u0131 veya hatalar\u0131 tespit edin.<\/li>\n<li>G\u00fcncelleme testleri, sistemlerinizin kararl\u0131l\u0131\u011f\u0131n\u0131 ve g\u00fcvenli\u011fini sa\u011flamak i\u00e7in \u00f6nemlidir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>Gereksiz \u00d6zellikleri Devre D\u0131\u015f\u0131 B\u0131rakma:<\/strong>GSSAPI kimlik do\u011frulamas\u0131 veya DNS \u00e7\u00f6z\u00fcmlemesi gibi gereksiz \u00f6zellikleri devre d\u0131\u015f\u0131 b\u0131rakarak, sald\u0131r\u0131 y\u00fczeyinizi azaltabilir ve performans\u0131 art\u0131rabilirsiniz.\n<ul>\n<li><strong><code>sshd_config<\/code> Dosyas\u0131n\u0131 D\u00fczenleme:<\/strong>\n<ul>\n<li><code>GSSAPIAuthentication no<\/code> olarak ayarlayarak GSSAPI kimlik do\u011frulamas\u0131n\u0131 devre d\u0131\u015f\u0131 b\u0131rak\u0131n.<\/li>\n<li><code>UseDNS no<\/code> olarak ayarlayarak DNS \u00e7\u00f6z\u00fcmlemesini devre d\u0131\u015f\u0131 b\u0131rak\u0131n.<\/li>\n<\/ul>\n<\/li>\n<li><strong>G\u00fcvenlik Risklerini De\u011ferlendirme:<\/strong>\n<ul>\n<li>Her \u00f6zelli\u011fi devre d\u0131\u015f\u0131 b\u0131rakmadan \u00f6nce, potansiyel g\u00fcvenlik risklerini ve performans etkilerini de\u011ferlendirin.<\/li>\n<li>Gereksiz \u00f6zellikleri devre d\u0131\u015f\u0131 b\u0131rakmak, sald\u0131r\u0131 y\u00fczeyinizi azalt\u0131rken, baz\u0131 durumlarda performans\u0131 art\u0131rabilir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Kullanma:<\/strong>SSH trafi\u011fini yaln\u0131zca belirli IP adreslerinden veya a\u011flardan gelen ba\u011flant\u0131lara izin verecek \u015fekilde yap\u0131land\u0131r\u0131lm\u0131\u015f bir g\u00fcvenlik duvar\u0131 kullanmak, yetkisiz eri\u015fimi \u00f6nlemenin etkili bir yoludur.\n<ul>\n<li><strong>Gelen ve Giden Trafik Kurallar\u0131:<\/strong>\n<ul>\n<li>G\u00fcvenlik duvar\u0131n\u0131zda, yaln\u0131zca belirli IP adreslerinden veya a\u011flardan gelen SSH trafi\u011fine izin veren gelen kurallar olu\u015fturun.<\/li>\n<li>Giden trafi\u011fi de k\u0131s\u0131tlayarak, sunucunuzdan d\u0131\u015f d\u00fcnyaya yap\u0131lan yetkisiz ba\u011flant\u0131lar\u0131 engelleyebilirsiniz.<\/li>\n<\/ul>\n<\/li>\n<li><strong>G\u00fcvenlik Duvar\u0131 Loglar\u0131n\u0131 \u0130zleme:<\/strong>\n<ul>\n<li>G\u00fcvenlik duvar\u0131 loglar\u0131n\u0131 d\u00fczenli olarak izleyerek, \u015f\u00fcpheli aktiviteleri ve yetkisiz eri\u015fim giri\u015fimlerini tespit edin.<\/li>\n<li>G\u00fcvenlik duvar\u0131 loglar\u0131, sald\u0131r\u0131lar\u0131 engellemek ve sistemlerinizi g\u00fcvende tutmak i\u00e7in de\u011ferli bilgiler sa\u011flar.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>SSH Ba\u011flant\u0131lar\u0131n\u0131 S\u00fcrekli \u0130zleme ve Y\u00f6netme<\/strong><\/p>\n<p>SSH ba\u011flant\u0131lar\u0131n\u0131 s\u00fcrekli olarak izlemek ve y\u00f6netmek, potansiyel sorunlar\u0131 erken tespit etmenize, g\u00fcvenlik ihlallerini \u00f6nlemenize ve sistemlerinizin performans\u0131n\u0131 optimize etmenize yard\u0131mc\u0131 olabilir. &#8220;SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr&#8221; sorusuna proaktif bir yakla\u015f\u0131mla yan\u0131t vermek i\u00e7in, s\u00fcrekli izleme ve y\u00f6netim stratejileri uygulamak \u00f6nemlidir.<\/p>\n<ul>\n<li><strong>Log Analiz Ara\u00e7lar\u0131 Kullanma:<\/strong>Log analiz ara\u00e7lar\u0131, SSH sunucu loglar\u0131n\u0131 otomatik olarak analiz ederek, ola\u011fand\u0131\u015f\u0131 aktiviteleri, hatalar\u0131 ve g\u00fcvenlik tehditlerini tespit etmenize yard\u0131mc\u0131 olabilir.\n<ul>\n<li><strong>Log Toplama ve Merkezile\u015ftirme:<\/strong>\n<ul>\n<li>SSH sunucu loglar\u0131n\u0131 merkezi bir log sunucusunda toplay\u0131n ve saklay\u0131n.<\/li>\n<li>Log toplama ve merkezile\u015ftirme, log analizini kolayla\u015ft\u0131r\u0131r ve g\u00fcvenlik olaylar\u0131n\u0131 takip etmenize yard\u0131mc\u0131 olur.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Log Analiz Ara\u00e7lar\u0131:<\/strong>\n<ul>\n<li>Splunk, ELK Stack (Elasticsearch, Logstash, Kibana), Graylog gibi log analiz ara\u00e7lar\u0131 kullan\u0131n.<\/li>\n<li>Bu ara\u00e7lar, loglar\u0131 otomatik olarak analiz eder, g\u00f6rselle\u015ftirir ve uyar\u0131lar olu\u015fturur.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Uyar\u0131lar ve Bildirimler:<\/strong>\n<ul>\n<li>Belirli olaylar (\u00f6rne\u011fin, ba\u015far\u0131s\u0131z kimlik do\u011frulama giri\u015fimleri, ola\u011fand\u0131\u015f\u0131 ba\u011flant\u0131 aktiviteleri) ger\u00e7ekle\u015fti\u011finde otomatik uyar\u0131lar ve bildirimler al\u0131n.<\/li>\n<li>Uyar\u0131lar ve bildirimler, h\u0131zl\u0131 bir \u015fekilde m\u00fcdahale etmenize ve sorunlar\u0131 \u00e7\u00f6zmenize yard\u0131mc\u0131 olur.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>SSH \u0130zleme Ara\u00e7lar\u0131 Kullanma:<\/strong>SSH izleme ara\u00e7lar\u0131, SSH ba\u011flant\u0131lar\u0131n\u0131 ger\u00e7ek zamanl\u0131 olarak izleyerek, kimin ne zaman ba\u011fland\u0131\u011f\u0131n\u0131, hangi komutlar\u0131 \u00e7al\u0131\u015ft\u0131rd\u0131\u011f\u0131n\u0131 ve ne kadar veri aktard\u0131\u011f\u0131n\u0131 g\u00f6rmenizi sa\u011flar.\n<ul>\n<li><strong>Ger\u00e7ek Zamanl\u0131 \u0130zleme:<\/strong>\n<ul>\n<li>SSH izleme ara\u00e7lar\u0131, SSH ba\u011flant\u0131lar\u0131n\u0131 ger\u00e7ek zamanl\u0131 olarak izleyerek, ola\u011fand\u0131\u015f\u0131 aktiviteleri ve g\u00fcvenlik tehditlerini tespit etmenize yard\u0131mc\u0131 olur.<\/li>\n<li>Ger\u00e7ek zamanl\u0131 izleme, h\u0131zl\u0131 bir \u015fekilde m\u00fcdahale etmenize ve sorunlar\u0131 \u00e7\u00f6zmenize olanak tan\u0131r.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Oturum Kayd\u0131:<\/strong>\n<ul>\n<li>SSH oturumlar\u0131n\u0131 kaydederek, kullan\u0131c\u0131lar\u0131n hangi komutlar\u0131 \u00e7al\u0131\u015ft\u0131rd\u0131\u011f\u0131n\u0131 ve ne t\u00fcr verilere eri\u015fti\u011fini takip edin.<\/li>\n<li>Oturum kayd\u0131, adli t\u0131p analizleri ve g\u00fcvenlik denetimleri i\u00e7in de\u011ferli bilgiler sa\u011flar.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Kullan\u0131c\u0131 Davran\u0131\u015f\u0131 Analizi:<\/strong>\n<ul>\n<li>SSH izleme ara\u00e7lar\u0131, kullan\u0131c\u0131 davran\u0131\u015flar\u0131n\u0131 analiz ederek, ola\u011fand\u0131\u015f\u0131 veya \u015f\u00fcpheli aktiviteleri tespit etmenize yard\u0131mc\u0131 olabilir.<\/li>\n<li>Kullan\u0131c\u0131 davran\u0131\u015f\u0131 analizi, i\u00e7eriden gelen tehditleri ve yetkisiz eri\u015fim giri\u015fimlerini tespit etmek i\u00e7in \u00f6nemlidir.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>SSH Anahtarlar\u0131n\u0131 D\u00fczenli Olarak Y\u00f6netme:<\/strong>SSH anahtarlar\u0131n\u0131 d\u00fczenli olarak y\u00f6netmek, kullan\u0131lmayan veya tehlikeye girmi\u015f anahtarlar\u0131 iptal etmek ve yeni anahtarlar olu\u015fturmak, g\u00fcvenli\u011fi art\u0131rman\u0131za yard\u0131mc\u0131 olur.\n<ul>\n<li><strong>Anahtar Envanteri:<\/strong>\n<ul>\n<li>T\u00fcm SSH anahtarlar\u0131n\u0131n bir envanterini olu\u015fturun ve hangi kullan\u0131c\u0131lar\u0131n hangi sunuculara eri\u015fim iznine sahip oldu\u011funu takip edin.<\/li>\n<li>Anahtar envanteri, anahtar y\u00f6netimini kolayla\u015ft\u0131r\u0131r ve g\u00fcvenlik risklerini tespit etmenize yard\u0131mc\u0131 olur.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Kullan\u0131lmayan Anahtarlar\u0131 \u0130ptal Etme:<\/strong>\n<ul>\n<li>Kullan\u0131lmayan veya eski anahtarlar\u0131 iptal ederek, yetkisiz eri\u015fim riskini azalt\u0131n.<\/li>\n<li>Kullan\u0131lmayan anahtarlar\u0131 d\u00fczenli olarak temizlemek, anahtar y\u00f6netimini basitle\u015ftirir ve g\u00fcvenli\u011fi art\u0131r\u0131r.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Anahtar Rotasyonu:<\/strong>\n<ul>\n<li>Anahtarlar\u0131 d\u00fczenli olarak d\u00f6nd\u00fcrerek, anahtar\u0131n tehlikeye girmesi durumunda potansiyel zarar\u0131 s\u0131n\u0131rlay\u0131n.<\/li>\n<li>Anahtar rotasyonu, g\u00fcvenlik risklerini azalt\u0131r ve sistemlerinizin g\u00fcvenli\u011fini sa\u011flar.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Anahtar G\u00fcvenli\u011fi:<\/strong>\n<ul>\n<li>\u00d6zel anahtarlar\u0131 g\u00fcvenli bir \u015fekilde saklay\u0131n ve yetkisiz eri\u015fime kar\u015f\u0131 koruyun.<\/li>\n<li>\u00d6zel anahtarlar\u0131 \u015fifreleyin ve eri\u015fim izinlerini k\u0131s\u0131tlay\u0131n.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>Otomatik Uyar\u0131lar Kurma:<\/strong>Belirli olaylar (\u00f6rne\u011fin, ba\u015far\u0131s\u0131z kimlik do\u011frulama giri\u015fimleri, ola\u011fand\u0131\u015f\u0131 ba\u011flant\u0131 aktiviteleri) ger\u00e7ekle\u015fti\u011finde otomatik uyar\u0131lar alarak, h\u0131zl\u0131 bir \u015fekilde m\u00fcdahale edebilirsiniz.\n<ul>\n<li><strong>Uyar\u0131 Kriterleri:<\/strong>\n<ul>\n<li>Ba\u015far\u0131s\u0131z kimlik do\u011frulama giri\u015fimleri, ola\u011fand\u0131\u015f\u0131 ba\u011flant\u0131 aktiviteleri, y\u00fcksek CPU kullan\u0131m\u0131, disk alan\u0131 dolulu\u011fu gibi uyar\u0131 kriterleri tan\u0131mlay\u0131n.<\/li>\n<li>Uyar\u0131 kriterleri, potansiyel sorunlar\u0131 ve g\u00fcvenlik tehditlerini tespit etmenize yard\u0131mc\u0131 olur.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Uyar\u0131 Kanallar\u0131:<\/strong>\n<ul>\n<li>E-posta, SMS, Slack veya di\u011fer ileti\u015fim kanallar\u0131 arac\u0131l\u0131\u011f\u0131yla uyar\u0131lar al\u0131n.<\/li>\n<li>Uyar\u0131 kanallar\u0131, h\u0131zl\u0131 bir \u015fekilde bilgilendirilmenizi ve m\u00fcdahale etmenizi sa\u011flar.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Uyar\u0131 \u00d6nceliklendirmesi:<\/strong>\n<ul>\n<li>Uyar\u0131lar\u0131 \u00f6nceliklendirerek, en kritik sorunlara \u00f6ncelik verin.<\/li>\n<li>Uyar\u0131 \u00f6nceliklendirmesi, kaynaklar\u0131n\u0131z\u0131 etkili bir \u015fekilde y\u00f6netmenize ve \u00f6nemli sorunlara odaklanman\u0131za yard\u0131mc\u0131 olur.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>\u00d6rnek Senaryolar<\/strong><\/p>\n<p>A\u015fa\u011f\u0131da, SSH ba\u011flant\u0131 problemlerini \u00f6nleme ve s\u00fcrekli izleme stratejilerinin nas\u0131l uygulanabilece\u011fine dair baz\u0131 \u00f6rnek senaryolar bulunmaktad\u0131r:<\/p>\n<ul>\n<li><strong>Senaryo 1: Bir \u015eirketin Sunucular\u0131n\u0131n G\u00fcvenli\u011fini Art\u0131rma<\/strong>Bir \u015firket, sunucular\u0131n\u0131n g\u00fcvenli\u011fini art\u0131rmak ve SSH ba\u011flant\u0131 problemlerini \u00f6nlemek i\u00e7in a\u015fa\u011f\u0131daki ad\u0131mlar\u0131 uygular:\n<ol>\n<li>Parola tabanl\u0131 kimlik do\u011frulamay\u0131 devre d\u0131\u015f\u0131 b\u0131rak\u0131r ve anahtar tabanl\u0131 kimlik do\u011frulamay\u0131 etkinle\u015ftirir.<\/li>\n<li>SSH portunu de\u011fi\u015ftirir ve g\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131 g\u00fcnceller.<\/li>\n<li>Fail2ban&#8217;\u0131 kurar ve yap\u0131land\u0131r\u0131r.<\/li>\n<li>\u0130ki fakt\u00f6rl\u00fc kimlik do\u011frulamay\u0131 etkinle\u015ftirir.<\/li>\n<li>SSH anahtarlar\u0131n\u0131n bir envanterini olu\u015fturur ve d\u00fczenli olarak y\u00f6netir.<\/li>\n<li>SSH sunucu loglar\u0131n\u0131 toplar ve analiz etmek i\u00e7in bir log analiz arac\u0131 kullan\u0131r.<\/li>\n<li>Ola\u011fand\u0131\u015f\u0131 aktiviteler i\u00e7in otomatik uyar\u0131lar kurar.<\/li>\n<\/ol>\n<\/li>\n<li><strong>Senaryo 2: Bir Geli\u015ftiricinin Uzak Sunucusuna G\u00fcvenli Bir \u015eekilde Eri\u015fme<\/strong>Bir geli\u015ftirici, uzak sunucusuna g\u00fcvenli bir \u015fekilde eri\u015fmek ve SSH ba\u011flant\u0131 problemlerini \u00f6nlemek i\u00e7in a\u015fa\u011f\u0131daki ad\u0131mlar\u0131 uygular:\n<ol>\n<li>G\u00fc\u00e7l\u00fc bir parola kullan\u0131r veya anahtar tabanl\u0131 kimlik do\u011frulamay\u0131 etkinle\u015ftirir.<\/li>\n<li>SSH istemcisini g\u00fcncel tutar.<\/li>\n<li>Sunucunun IP adresini ve port numaras\u0131n\u0131 do\u011fru bir \u015fekilde yap\u0131land\u0131r\u0131r.<\/li>\n<li>TCP Keep-Alive ayarlar\u0131n\u0131 etkinle\u015ftirir.<\/li>\n<li>G\u00fcvenlik duvar\u0131 ayarlar\u0131n\u0131n SSH trafi\u011fine izin verdi\u011finden emin olur.<\/li>\n<li>Sunucunun loglar\u0131n\u0131 d\u00fczenli olarak kontrol eder.<\/li>\n<\/ol>\n<\/li>\n<li><strong>Senaryo 3: Bir Sistem Y\u00f6neticisinin Bulut Ortam\u0131ndaki SSH Ba\u011flant\u0131lar\u0131n\u0131 Y\u00f6netme<\/strong>Bir sistem y\u00f6neticisi, bulut ortam\u0131ndaki SSH ba\u011flant\u0131lar\u0131n\u0131 y\u00f6netmek ve g\u00fcvenlik risklerini azaltmak i\u00e7in a\u015fa\u011f\u0131daki ad\u0131mlar\u0131 uygular:\n<ol>\n<li>Bulut sa\u011flay\u0131c\u0131s\u0131n\u0131n g\u00fcvenlik gruplar\u0131n\u0131 veya a\u011f g\u00fcvenlik gruplar\u0131n\u0131 kullanarak SSH trafi\u011fini k\u0131s\u0131tlar.<\/li>\n<li>SSH anahtarlar\u0131n\u0131n bir envanterini olu\u015fturur ve d\u00fczenli olarak y\u00f6netir.<\/li>\n<li>Bulut sa\u011flay\u0131c\u0131s\u0131n\u0131n log analiz ara\u00e7lar\u0131n\u0131 kullanarak SSH sunucu loglar\u0131n\u0131 analiz eder.<\/li>\n<li>Bulut sa\u011flay\u0131c\u0131s\u0131n\u0131n izleme ara\u00e7lar\u0131n\u0131 kullanarak SSH ba\u011flant\u0131lar\u0131n\u0131 ger\u00e7ek zamanl\u0131 olarak izler.<\/li>\n<li>Ola\u011fand\u0131\u015f\u0131 aktiviteler i\u00e7in otomatik uyar\u0131lar kurar.<\/li>\n<\/ol>\n<\/li>\n<\/ul>\n<p>&#8220;SSH ba\u011flant\u0131 problemleri nas\u0131l \u00e7\u00f6z\u00fcl\u00fcr&#8221; sorusuna en iyi yan\u0131t, sorunlar\u0131 en ba\u015ftan \u00f6nlemektir. G\u00fc\u00e7l\u00fc g\u00fcvenlik \u00f6nlemleri uygulamak, d\u00fczenli olarak izleme yapmak ve proaktif bir yakla\u015f\u0131mla sorunlar\u0131 tespit etmek, SSH ba\u011flant\u0131 problemlerini en aza indirmenize, sistemlerinizin g\u00fcvenli\u011fini art\u0131rman\u0131za ve performans\u0131n\u0131z\u0131 optimize etmenize yard\u0131mc\u0131 olacakt\u0131r. Bu rehber boyunca ele al\u0131nan stratejileri ve en iyi uygulamalar\u0131 uygulayarak, SSH ba\u011flant\u0131 sorunlar\u0131yla kar\u015f\u0131la\u015ft\u0131\u011f\u0131n\u0131zda h\u0131zl\u0131 ve etkili bir \u015fekilde m\u00fcdahale edebilir ve sistemlerinizin sorunsuz bir \u015fekilde \u00e7al\u0131\u015fmas\u0131n\u0131 sa\u011flayabilirsiniz. SSH, modern bili\u015fim altyap\u0131s\u0131n\u0131n temel bir par\u00e7as\u0131d\u0131r ve g\u00fcvenli ve g\u00fcvenilir bir \u015fekilde kullan\u0131lmas\u0131, sistemlerinizin b\u00fct\u00fcnl\u00fc\u011f\u00fc ve gizlili\u011fi i\u00e7in kritik \u00f6neme sahiptir. Unutmay\u0131n, g\u00fcvenlik s\u00fcrekli bir s\u00fcre\u00e7tir ve d\u00fczenli olarak g\u00f6zden ge\u00e7irilmesi ve g\u00fcncellenmesi gerekir.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>SSH Ba\u011flant\u0131 Problemleri Nas\u0131l \u00c7\u00f6z\u00fcl\u00fcr? Kesin \u00c7\u00f6z\u00fcm Rehberi 1. Giri\u015f: SSH Ba\u011flant\u0131 Problemlerine Genel Bak\u0131\u015f ve \u00d6nemi SSH Nedir ve Neden Kullan\u0131l\u0131r? G\u00fcvenli Kabuk (Secure Shell), yayg\u0131n olarak SSH olarak bilinen, iki a\u011f cihaz\u0131 aras\u0131nda g\u00fcvenli bir kanal \u00fczerinden ileti\u015fim kurmay\u0131 sa\u011flayan bir a\u011f protokol\u00fcd\u00fcr. SSH, \u00f6zellikle uzaktan eri\u015fim, dosya transferi ve komut \u00e7al\u0131\u015ft\u0131rma gibi [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":9102,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[123],"tags":[17637,17639,17638,17636,17653,17659,17635,17647,17655,17650,17640,17657,17651,17634,17633,17632,17643,17641,17645,17644,17642,17656,17646,17649,17648,17658,17652,17654,11219],"class_list":["post-9101","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-web-hosting","tag-ssh-baglanti-hatasi","tag-ssh-firewall","tag-ssh-kimlik-dogrulama","tag-ssh-sorun-giderme","tag-ssh-authentication-failed","tag-ssh-baglanti-hata-kodlari","tag-ssh-baglanti-hatalari","tag-ssh-baglanti-hatasi-cozumu","tag-ssh-baglanti-hatasi-giderme","tag-ssh-baglanti-kopuyor","tag-ssh-baglanti-kurulamadi","tag-ssh-baglanti-problemi-cozumu","tag-ssh-baglanti-problemi-nasil-cozulur","tag-ssh-baglanti-problemleri","tag-ssh-baglanti-problemleri-nasil-cozulur","tag-ssh-baglanti-problemleri-nasil-cozulur-kesin-cozum-rehberi","tag-ssh-baglantisi-kesiliyor","tag-ssh-connection-refused","tag-ssh-connection-timed-out","tag-ssh-erisim-engellendi","tag-ssh-erisim-sorunu","tag-ssh-ile-giris-yapilamiyor","tag-ssh-ile-sunucuya-baglanamiyorum","tag-ssh-port-hatasi","tag-ssh-public-key-hatasi","tag-ssh-server-baglanti-sorunu","tag-ssh-sunucu-baglanti-sorunu","tag-ssh-troubleshooting","tag-ssh-yapilandirma"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v23.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>SSH Ba\u011flant\u0131 Problemleri Nas\u0131l \u00c7\u00f6z\u00fcl\u00fcr? 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