After updating mailcow to the latest 2/2025 I’m getting this message in mc logfiles every minute or less:
dovecot: auth-worker(xx): conn unix:auth-worker (pid=xxx,uid=xxx): auth-worker<xxx>: sql(watchdog@invalid, xxx.xxx.xxx.xxx): unknown user
Does anyone know where this may come from (fail2ban) and why this occurs after updating?
Anything else seems to be quite fine 🙂

  • DocFraggle

    • Community Hero
    Moolevel 282
  • Post #2

My dovecot log shows the same message

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  • esackbauer

    • Community Hero
    Moolevel 381
  • Post #3
  • Edited

If you look at the surrounding log lines and the IP address, you will notice that it is the watchdog testing if dovecot ist still running.
I bet is has been there before 😉 If not, maybe devs changed the watchdog.

No, I have two instances of mailcow running, one still @ 11/24 and this one has this log:
Connect from 172.22.1.8#015
dovecot: lmtp(124754): Disconnect from 172.22.1.8: Logged out (state=MAIL FROM)#015

This seems (at least from my point of view) not as problematic.
I just hope that watchdog does not trigger netfilter/fail2ban to blacklist itself.
The “unknown user” message is a fail2ban message for the dovecot filter

    • esackbauer

      • Community Hero
      Moolevel 381
    • Post #5

    yoobeedoobee
    The “unkown user” is because the watchdog only connects and waits for the welcome string. It then disconnects without further authentication, hence the user is unkown.

    yoobeedoobee I just hope that watchdog does not trigger netfilter/fail2ban to blacklist itself.

    If that would be the case everyone would have this problems since quite some time 😉

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