{"id":5390,"date":"2026-05-15T01:01:34","date_gmt":"2026-05-14T22:01:34","guid":{"rendered":"https:\/\/hostingdunyam.com.tr\/blog\/?p=5390"},"modified":"2026-05-15T01:03:08","modified_gmt":"2026-05-14T22:03:08","slug":"fail2ban-nedir","status":"publish","type":"post","link":"https:\/\/hostingdunyam.com.tr\/blog\/fail2ban-nedir","title":{"rendered":"Fail2Ban Nedir?"},"content":{"rendered":"

Fail2Ban, Linux sunucularda ba\u015far\u0131s\u0131z giri\u015f denemelerini izleyen ve belirli bir e\u015fi\u011fi a\u015fan IP adreslerini otomatik olarak engelleyen a\u00e7\u0131k kaynakl\u0131 bir g\u00fcvenlik arac\u0131d\u0131r. \u00d6zellikle SSH, FTP ve web panellerini hedef alan brute-force sald\u0131r\u0131lar\u0131na kar\u015f\u0131 etkili bir ilk savunma katman\u0131 olu\u015fturur.<\/span><\/p>\n

Fail2Ban Nas\u0131l \u00c7al\u0131\u015f\u0131r?<\/span><\/h2>\n

Fail2Ban’\u0131n \u00e7al\u0131\u015fma mant\u0131\u011f\u0131 \u00fc\u00e7 temel kavram \u00fczerine kuruludur.<\/span><\/p>\n

    \n
  1. Jail (Hapishane):<\/b> Belirli bir servis i\u00e7in izleme kurallar\u0131n\u0131n b\u00fct\u00fcn\u00fcn\u00fc tan\u0131mlar. Hangi log dosyas\u0131n\u0131n izlenece\u011fini, ka\u00e7 ba\u015far\u0131s\u0131z denemeden sonra ban uygulanaca\u011f\u0131n\u0131 ve ban s\u00fcresini belirtir.<\/span><\/li>\n
  2. Filter (Filtre):<\/b> Log dosyalar\u0131ndan ba\u015far\u0131s\u0131z giri\u015f denemelerini yakalamak i\u00e7in kullan\u0131lan regex kal\u0131plar\u0131d\u0131r. SSH, FTP, Postfix gibi pop\u00fcler servisler i\u00e7in haz\u0131r filtrelerle birlikte gelir.<\/span><\/li>\n
  3. Action (Eylem):<\/b> Bir IP ban e\u015fi\u011fini a\u015ft\u0131\u011f\u0131nda Fail2Ban devreye girer ve iptables, firewalld veya nftables arac\u0131l\u0131\u011f\u0131yla o IP’ye gelen ba\u011flant\u0131lar\u0131 engeller. Ban s\u00fcresi doldu\u011funda engel otomatik olarak kalkar.<\/span><\/li>\n<\/ol>\n

    Fail2Ban Hangi Servisleri Koruyabilir?<\/span><\/h2>\n

    Fail2Ban yaln\u0131zca SSH i\u00e7in de\u011fil, log dosyas\u0131 \u00fcreten hemen her servis i\u00e7in kullan\u0131labilir. Haz\u0131r filtrelerle desteklenen ba\u015fl\u0131ca servisler: SSH\/SFTP, Apache, Nginx, Postfix, Dovecot, ProFTPD, vsftpd, MySQL ve cPanel\/Plesk gibi kontrol panelleri.<\/span><\/p>\n

    Fail2Ban Kurulumu<\/span><\/h2>\n

    Debian \/ Ubuntu<\/span><\/h3>\n

    bash<\/span><\/p>\n

    sudo<\/span> apt<\/span> update<\/span><\/span><\/p>\n

    sudo<\/span> apt<\/span> install<\/span> fail2ban -y<\/span><\/span><\/p>\n

    RHEL \/ CentOS \/ AlmaLinux<\/span><\/h3>\n

    bash<\/span><\/p>\n

    sudo<\/span> dnf <\/span>install<\/span> epel-release -y<\/span><\/span><\/p>\n

    sudo<\/span> dnf <\/span>install<\/span> fail2ban -y<\/span><\/span><\/p>\n

    Kurulumun ard\u0131ndan servisi ba\u015flat\u0131n:<\/span><\/p>\n

    bash<\/span><\/p>\n

    sudo<\/span> systemctl <\/span>enable<\/span> fail2ban<\/span><\/span><\/p>\n

    sudo<\/span> systemctl start fail2ban<\/span><\/span><\/p>\n

    Temel Yap\u0131land\u0131rma<\/span><\/h2>\n

    Ana yap\u0131land\u0131rma dosyas\u0131 <\/span>\/etc\/fail2ban\/jail.conf<\/span>‘tur. Ancak bu dosyay\u0131 do\u011frudan d\u00fczenlemek \u00f6nerilmez; g\u00fcncellemelerle \u00fczerine yaz\u0131labilir. Bunun yerine <\/span>jail.local<\/span> dosyas\u0131 olu\u015fturun:<\/span><\/p>\n

    bash<\/span><\/p>\n

    sudo<\/span> cp<\/span> \/etc\/fail2ban\/jail.conf \/etc\/fail2ban\/jail.local<\/span><\/span><\/p>\n

    sudo<\/span> nano<\/span> \/etc\/fail2ban\/jail.local<\/span><\/span><\/p>\n

    Temel ayarlar:<\/span><\/p>\n

    ini<\/span><\/p>\n

    [<\/span>DEFAULT<\/span>]<\/span><\/span><\/p>\n

    bantime<\/span>\u00a0 <\/span>=<\/span> 1h \u00a0 \u00a0 \u00a0 # Ban s\u00fcresi<\/span><\/p>\n

    findtime<\/span> =<\/span> 10m\u00a0 \u00a0 \u00a0 # Deneme sayac\u0131n\u0131n s\u0131f\u0131rlanma s\u00fcresi<\/span><\/p>\n

    maxretry<\/span> =<\/span> 5\u00a0 \u00a0 \u00a0 \u00a0 # Maksimum ba\u015far\u0131s\u0131z deneme say\u0131s\u0131<\/span><\/p>\n

    ignoreip<\/span> =<\/span> 127.0.0.1\u00a0 # Asla banlanmayacak IP’ler<\/span><\/p>\n

    SSH i\u00e7in jail etkinle\u015ftirme:<\/span><\/p>\n

    ini<\/span><\/p>\n

    [<\/span>sshd<\/span>]<\/span><\/span><\/p>\n

    enabled<\/span>\u00a0 <\/span>=<\/span> true<\/span><\/p>\n

    port<\/span> \u00a0 \u00a0 <\/span>=<\/span> ssh<\/span><\/p>\n

    filter<\/span> \u00a0 <\/span>=<\/span> sshd<\/span><\/p>\n

    logpath<\/span>\u00a0 <\/span><\/span>=<\/span> \/var\/log\/auth.log<\/span><\/p>\n

    maxretry<\/span> =<\/span> 3<\/span><\/p>\n

    Y\u00f6netim Komutlar\u0131<\/span><\/h2>\n

    Aktif jailleri listele:<\/span><\/p>\n

    bash<\/span><\/p>\n

    sudo<\/span> fail2ban-client status<\/span><\/span><\/p>\n

    SSH jail durumunu g\u00f6r\u00fcnt\u00fcle:<\/span><\/p>\n

    bash<\/span><\/p>\n

    sudo<\/span> fail2ban-client status sshd<\/span><\/span><\/p>\n

    Bir IP’yi manuel olarak banla:<\/span><\/p>\n

    bash<\/span><\/p>\n

    sudo<\/span> fail2ban-client <\/span>set<\/span> sshd banip <\/span>1.2<\/span>.3.4<\/span><\/span><\/p>\n

    Banl\u0131 bir IP’yi serbest b\u0131rak:<\/span><\/p>\n

    bash<\/span><\/p>\n

    sudo<\/span> fail2ban-client <\/span>set<\/span> sshd unbanip <\/span>1.2<\/span>.3.4<\/span><\/span><\/p>\n

    Canl\u0131 log takibi:<\/span><\/p>\n

    bash<\/span><\/p>\n

    sudo<\/span> tail<\/span> -f \/var\/log\/fail2ban.log<\/span><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

    Fail2Ban, Linux sunucularda ba\u015far\u0131s\u0131z giri\u015f denemelerini izleyen ve belirli bir e\u015fi\u011fi a\u015fan IP adreslerini otomatik olarak engelleyen a\u00e7\u0131k kaynakl\u0131 bir g\u00fcvenlik arac\u0131d\u0131r. \u00d6zellikle SSH, FTP ve web panellerini hedef alan brute-force sald\u0131r\u0131lar\u0131na kar\u015f\u0131 etkili bir ilk savunma katman\u0131 olu\u015fturur. Fail2Ban Nas\u0131l \u00c7al\u0131\u015f\u0131r? Fail2Ban’\u0131n \u00e7al\u0131\u015fma mant\u0131\u011f\u0131 \u00fc\u00e7 temel kavram \u00fczerine kuruludur. Jail (Hapishane): Belirli bir servis […]<\/p>\n","protected":false},"author":1,"featured_media":5391,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-5390","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-genel"],"_links":{"self":[{"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/posts\/5390","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/comments?post=5390"}],"version-history":[{"count":1,"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/posts\/5390\/revisions"}],"predecessor-version":[{"id":5392,"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/posts\/5390\/revisions\/5392"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/media\/5391"}],"wp:attachment":[{"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/media?parent=5390"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/categories?post=5390"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hostingdunyam.com.tr\/blog\/wp-json\/wp\/v2\/tags?post=5390"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}