Fail2ban不禁止IP地址

我安裝fail2ban在 Ubuntu 20.04 伺服器上。我已經關注了一些關於如何配置它的文章，但它不起作用。我已經進行了 10 次錯誤的登錄嘗試，但仍然沒有被禁止。

/etc/fail2ban/jail.local:

[sshd]

enabled  = true
port     = 27485
filter   = sshd
logpath  = /var/log/auth.log
maxretry = 3
bantime = 4w
findtime = 1d

/var/log/auth.log:

sudo:  user : TTY=pts/3 ; PWD=/home/user ; USER=root ; COMMAND=/usr/bin/tail -f /var/log/auth.log
sudo: pam_unix(sudo:session): session opened for user root by user(uid=0)
sshd[23907]: Connection closed by authenticating user user 111.1.1.1 port 8825 [preauth]
sshd[23909]: Connection closed by authenticating user user 111.1.1.1 port 8827 [preauth]
sshd[23911]: Connection closed by authenticating user user 111.1.1.1 port 8828 [preauth]
sshd[23913]: Connection closed by authenticating user user 111.1.1.1 port 8829 [preauth]
sshd[23915]: Connection closed by authenticating user user 111.1.1.1 port 8830 [preauth]

我在這裡做錯了什麼？我跑了systemctl status fail2ban，它正在執行。restarted保存配置後我也有。

你能從你的/var/log/auth.log.

我嘗試使用不存在的使用者進行本地測試，這就是我在日誌中看到的內容（在 ubuntu 20.04 實例上）

Oct 23 16:23:48 vps-34 sshd[35253]: Invalid user adminxxx from 123.123.123.123 port 35382
Oct 23 16:23:50 vps-34 sshd[35253]: pam_unix(sshd:auth): check pass; user unknown
Oct 23 16:23:50 vps-34 sshd[35253]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=123.123.123.123
Oct 23 16:23:52 vps-34 sshd[35253]: Failed password for invalid user adminxxx from 54.38.78.234 port 35382 ssh2
Oct 23 16:23:55 vps-34 sshd[35253]: Connection closed by invalid user adminxxx 54.38.78.234 port 35382 [preauth]

顯然，除非 sshd 記錄失敗，否則fail2ban 無法獲取…

可能，您有 ssh-agent 或其他一些自動將您登錄到伺服器的方法…

你可以試試這樣的東西：

ssh -o PreferredAuthentications=password -o PubkeyAuthentication=no -o  ControlPath=none example.com

（強制它使用密碼驗證）並同時跟踪日誌：

# tail -f  /var/log/auth.log

引用自：https://serverfault.com/questions/1039847