我有一台包含几十个 IMAP 帐户的邮件服务器。每个帐户的配置都是正确的，每个帐户的测试都正常。
当某个非常慢的 Internet 连接上的客户端尝试连接时，我会收到如下消息：
Mar 14 07:58:31 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 2 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<ETMgqX9mDraoAyqn>
Mar 14 07:58:31 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 2 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<EPggqX9mfqGoAyqn>
Mar 14 07:58:31 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 2 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<E3kgqX9mYJioAyqn>
Mar 14 07:58:37 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 4 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<YCZXqX9mHZSoAyqn>
Mar 14 07:58:37 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 4 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<5/JcqX9miKaoAyqn>
Mar 14 07:58:37 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 4 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<HTJYqX9m1p+oAyqn>
Mar 14 08:00:11 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 3 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<pesGr39mrICoAyqn>
Mar 14 08:00:11 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 3 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<bJ0Gr39mqYqoAyqn>
Mar 14 08:00:11 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 3 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<La0Gr39muZ2oAyqn>
Mar 14 08:02:08 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 2 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<lQsHtn9mH62oAyqn>
Mar 14 08:02:08 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 2 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<V8sHtn9mXruoAyqn>
Mar 14 08:02:08 mailserv dovecot: imap-login: Aborted login (auth failed, 2 attempts in 2 secs): user=<>, method=LOGIN, rip=111.111.111.111, lip=222.222.222.222, TLS, session=<WSIHtn9m5beoAyqn>
这里的客户端是111.111.111.111，服务器是222.222.222.222。
客户端可以同时成功查询服务器上的三个帐户。他们不知道从其客户端机器查询的任何其他帐户。
出现该问题的可能性在于，计算机上的第二个被遗忘的邮件程序在用户（非计算机人员）不知情的情况下尝试连接，或者由于客户端计算机的互联网连接非常慢（调制解调器拨号）而导致超时问题。
因此我的问题是：
我能否找出这些失败的连接尝试中使用的用户名和客户端用户代理（甚至密码）？我尝试设置
debug_log_path = /var/log/dovecot-debug.log auth_debug = yes
但是，我在这些（非常嘈杂的）日志中找不到任何相关信息，也许是错误的日志文件记录了失败（或超时）的尝试？为什么日志显示“ user=<>”？我可以让那条日志更有帮助吗？
我可以询问 dovecot 这些是错误的密码还是超时？我已经设置了
auth_policy_server_timeout_msecs = 17000
（默认 3000）无济于事 - 但另一方面，日志确实说“2 秒内尝试 2 次”，所以我可以排除超时吗？