有人在掃描我的 postfix/dovecot

有人在掃描我的郵件伺服器。

我能做些什麼來阻止他們？

我嘗試添加它並沒有幫助：

/etc/hosts.deny
ALL: 80.82.77.18

我在日誌中看到了這個：

...
Aug 23 03:34:40 auth-worker(1664): Info: sql(torcac@example.net,80.82.77.18): unknown user (given password: torcac)
Aug 23 03:35:17 auth-worker(1664): Info: sql(roselia@example.net,80.82.77.18): unknown user (given password: roselia)
Aug 23 03:35:56 auth-worker(1664): Info: sql(japan@example.net,80.82.77.18): unknown user (given password: japan)
Aug 23 03:36:35 auth-worker(1664): Info: sql(berta@example.net,80.82.77.18): unknown user (given password: berta)
Aug 23 03:37:08 auth-worker(1664): Info: sql(blue,193.169.252.176): unknown user (given password: 123456)
Aug 23 03:37:12 auth-worker(1664): Info: sql(keely@example.net,80.82.77.18): unknown user (given password: keely)
Aug 23 03:37:49 auth-worker(1664): Info: sql(marcelia@example.net,80.82.77.18): unknown user (given password: marcelia)
Aug 23 03:38:26 auth-worker(1664): Info: sql(yate@example.net,80.82.77.18): unknown user (given password: yate)
Aug 23 03:39:02 auth-worker(1664): Info: sql(silvie@example.net,80.82.77.18): unknown user (given password: silvie)
Aug 23 03:39:41 auth-worker(1664): Info: sql(seven@example.net,80.82.77.18): unknown user (given password: seven)ang@example.net,80.82.77.18): unknown user (given password: bang)
...

來自importgeek.wordpress.com：

1. 安裝 Fail2Ban

:apt-get install fail2ban 2. 要限制記憶體使用，請添加到 /etc/default/fail2ban：

+ulimit -s 256 3. 創建一個本地配置文件 /etc/fail2ban/jail.local 以覆蓋 jail.conf 中的設置：

:cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

:vi /etc/fail2ban/jail.local

[dovecot]
enabled = true
port = pop3,pop3s,imap,imaps
filter = dovecot
logpath = /var/log/mail.log
maxretry  = 3

[postfix]
enabled  = true
port     = smtp,ssmtp
filter   = postfix
logpath  = /var/log/mail.log
maxretry  = 3

[sasl]
enabled   = true
port      = smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter    = sasl
logpath   = /var/log/mail.log
maxretry  = 3

編輯

Fail2ban (Debian Squeeze) 未附帶 Dovecot 的配置，因此請創建 /etc/fail2ban/filter.d/dovecot.conf：

[Definition]
failregex = (?: pop3-login|imap-login): .*(?:Authentication failure|Aborted login \(auth failed|Aborted login \(tried to use disabled|Disconnected \(auth failed).*rip=(?P\S*),.*
ignoreregex =

重啟fail2ban：

# /etc/init.d/fail2ban restart

引用自：https://serverfault.com/questions/980423