从几天前开始，我在检查 /var/log/exim_mainlog 时，每隔几分钟就会看到来自本地主机的重复 SMTP 连接
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
似乎连接已启动，但一秒钟后就停止了。有人知道是什么原因造成的吗？谢谢。
答案1
考虑到规律性（5 分钟）以及与exim -bpc调用（检查邮件队列状态）的相关性，我猜测它会是某种监控探测器（nagios 插件或类似的东西）来检查您的 SMTPd 是否健康。