I flushed the postfix queue while monitoring the zimbra.log and that's when I spotted this.
Code:
Passed BAD-HEADER, [10.10.10.249] [10.10.10.249] <user@hotmail.com> -> <info@domin.tld>, quarantine: badh-pTm9BwhiWgVW, Message-ID: <1257755229@www.domin.tld>, mail_id: pTm9BwhiWgVW, Hits: 3.218, size: 672, queued_as: 5192B1A80145, 4868 ms
Followed up by tracing it's id.
Code:
[root@mail ~]# grep 5192B1A80145 /var/log/zimbra.log | tail -20
Nov 9 09:27:19 mail postfix/smtpd[3132]: 5192B1A80145: client=localhost.localdomain[127.0.0.1]
Nov 9 09:27:19 mail postfix/cleanup[27767]: 5192B1A80145: message-id=<1257755229@www.domain.tld>
Nov 9 09:27:19 mail postfix/qmgr[27391]: 5192B1A80145: from=<remote_user@hotmail.com>, size=1252, nrcpt=1 (queue active)
Nov 9 09:27:19 mail amavis[29168]: (29168-03) FWD via SMTP: <remote_user@hotmail.com> -> <info@domain.tld>, 250 2.6.0 Ok, id=29168-03, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 5192B1A80145
Nov 9 09:27:19 mail amavis[29168]: (29168-03) Passed BAD-HEADER, [10.10.10.249] [10.10.10.249] <remote_user@hotmail.com> -> <info@domain.tld>, quarantine: badh-pTm9BwhiWgVW, Message-ID: <1257755229@www.domain.tld>, mail_id: pTm9BwhiWgVW, Hits: 3.218, size: 672, queued_as: 5192B1A80145, 4868 ms
Nov 9 09:27:19 mail postfix/smtp[32194]: 4C2DE1A802A2: to=<info@domain.tld>, relay=127.0.0.1[127.0.0.1]:10024, delay=5.1, delays=0.25/0/0/4.9, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 5192B1A80145)
Nov 9 09:27:19 mail postfix/qmgr[27391]: 5192B1A80145: to=<info@domain.tld>, relay=none, delay=0.26, delays=0.09/0.17/0/0, dsn=4.3.0, status=deferred (mail transport unavailable)
Nov 9 09:36:50 mail postfix/qmgr[27391]: 5192B1A80145: from=<remote_user@hotmail.com>, size=1252, nrcpt=1 (queue active)
Nov 9 09:36:50 mail postfix/smtp[9108]: 5192B1A80145: to=<info@domain.tld>, relay=none, delay=571, delays=571/0.01/0/0, dsn=4.4.1, status=deferred (connect to mail.domain.tld[10.10.10.119]: Connection refused)
I suspect this could be one of the reasons why the deferred queue has grown. Is there any way I could force amavis to accept the headers while I figure out why the headers are regarded as invalid? I really need to get all the deferred mailed delivered.