來自本地主機的 SMTP 連接

從幾天前開始，我在檢查 /var/log/exim_mainlog 時每隔幾分鐘就會看到來自 localhost 的反复 SMTP 連接

2015-05-08 13:34:41 SMTP connection from [127.0.0.1]:48724 (TCP/IP connection count = 1)
2015-05-08 13:34:42 SMTP connection from localhost [127.0.0.1]:48724 closed by QUIT
2015-05-08 13:35:29 cwd=/etc/csf 2 args: /usr/sbin/exim -bpc
2015-05-08 13:39:44 SMTP connection from [127.0.0.1]:48748 (TCP/IP connection count = 1)
2015-05-08 13:39:45 SMTP connection from localhost [127.0.0.1]:48748 closed by QUIT
2015-05-08 13:40:29 cwd=/etc/csf 2 args: /usr/sbin/exim -bpc
2015-05-08 13:44:48 SMTP connection from [127.0.0.1]:48774 (TCP/IP connection count = 1)
2015-05-08 13:44:49 SMTP connection from localhost [127.0.0.1]:48774 closed by QUIT
2015-05-08 13:45:29 cwd=/etc/csf 2 args: /usr/sbin/exim -bpc
2015-05-08 13:49:50 SMTP connection from [127.0.0.1]:48800 (TCP/IP connection count = 1)
2015-05-08 13:49:51 SMTP connection from localhost [127.0.0.1]:48800 closed by QUIT
2015-05-08 13:50:29 cwd=/etc/csf 2 args: /usr/sbin/exim -bpc

似乎連接開始，然後在一秒鐘後停止。有誰知道是什麼原因造成的？謝謝。

鑑於規律性（5 分鐘）和與exim -bpc呼叫的相關性（檢查郵件隊列狀態），我猜這將是某種監視探針（nagios 外掛或類似的東西）來檢查您的 SMTPd 是否健康.

引用自：https://serverfault.com/questions/690579