I have a mail server using dovecot that has been running without issue for quite a couple of years now. It serves email for about 30 individuals.
But since Jan 14th, users have been reporting spurious errors in MS Outlook:
316 Jan 21 00:38:12 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 1 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=783) failed: Connection reset by peer, session=<yVd4Hm4Pst12wSuN>
317 Jan 21 00:38:12 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=598) failed: Connection reset by peer, session=<aKOAHm4PCOB2wSuN>
318 Jan 21 00:38:13 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=598) failed: Connection reset by peer, session=<9rWIHm4PtuF2wSuN>
319 Jan 21 00:38:13 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=677) failed: Connection reset by peer, session=<NsORHm4P9OJ2wSuN>
320 Jan 21 00:38:14 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=691) failed: Connection reset by peer, session=<AACaHm4PdOR2wSuN>
321 Jan 21 00:38:15 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 1 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=610) failed: Connection reset by peer, session=<G8umHm4P2OV2wSuN>
322 Jan 21 00:38:16 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 1 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=609) failed: Connection reset by peer, session=<qSy0Hm4PuOd2wSuN>
323 Jan 21 00:38:16 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=596) failed: Connection reset by peer, session=<W427Hm4PtOl2wSuN>
324 Jan 21 00:38:17 ip-172-30-0-131 dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=118.xxx.xxx.xxx, lip=172.30.0.131, TLS handshaking: read(size=596) failed: Connection reset by peer, session=
Some characteristics of the problem that may offer a clue:
- happening with multiple users, not just the same one
- happens from different IP addresses.
- happens about 3 to 5 times per day and the errors come in batches like above
- MS Outlook error is:
reported error (0x80042109): ‘Outlook cannot conect to your outgoing SMTP email server. If you continue to receive this message….blah blah blah
I googled the error code but didn’t find anything particularly helpful.
I’m running Debian bullseye, version 11.8.