Email out problem only for certain domains (dsn=5.0.0 relay=none)

[cadman]

First of all, much love for zimbra and thanks to all you mods, admins and coders that made it happen.

I am having a problem that only has happened a couple of times on certain domains. The message attempts to send but bounces back with no error information. its consistent and repeatable but it only happens for certain domains and it only happens every once in a while.

we are running Release 5.0.18_GA_3011.UBUNTU8_64 UBUNTU8_64 FOSS edition

Note: different edition than the non-community edition i run on our other server noted in my zimbra:stats

Here is a snippet from /var/log/zimbra.log:

bns@bns-mx01:~$ tail -n 50000 /var/log/zimbra.log | grep 0A17F2EC124
Sep 10 16:50:26 bns-mx01 postfix/smtpd[5745]: 0A17F2EC124: client=localhost[127.0.0.1]
Sep 10 16:50:26 bns-mx01 postfix/cleanup[11978]: 0A17F2EC124: message-id=<000301ca3271$6f2db480$4d891d80$@com>
Sep 10 16:50:26 bns-mx01 postfix/qmgr[7861]: 0A17F2EC124: from=<from-addr@xxx.com>, size=62449, nrcpt=1 (queue active)
Sep 10 16:50:26 bns-mx01 amavis[10047]: (10047-18) FWD via SMTP: <from-addr@xxx.com> -> <to-addr@zzz.com>,BODY=7BIT 250 2.6.0 Ok, id=10047-18, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 0A17F2EC124
Sep 10 16:50:26 bns-mx01 amavis[10047]: (10047-18) Passed CLEAN, [x.x.x.x] [x.x.x.x] <from-addr@xxx.com> -> <to-addr@zzz.com>, Message-ID: <000301ca3271$6f2db480$4d891d80$@com>, mail_id: CbIOXLMr-3LH, Hits: -0.179, size: 61971, queued_as: 0A17F2EC124, 4004 ms
Sep 10 16:50:26 bns-mx01 postfix/smtp[8152]: 7CDEB2EC113: to=<to-addr@zzz.com>, relay=127.0.0.1[127.0.0.1]:10024, delay=4.6, delays=0.59/0/0/4, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 0A17F2EC124)
Sep 10 16:50:26 bns-mx01 postfix/error[12974]: 0A17F2EC124: to=<to-addr@zzz.com>, relay=none, delay=0.06, delays=0.04/0.01/0/0.01, dsn=5.0.0, status=bounced (zzz.com)
Sep 10 16:50:26 bns-mx01 postfix/bounce[12975]: 0A17F2EC124: sender non-delivery notification: 190922EC132
Sep 10 16:50:26 bns-mx01 postfix/qmgr[7861]: 0A17F2EC124: removed

Note: Log has been manipulated to remove IP and email address info. but it is the address to-addr@zzz.com that is bouncing.

When we get the bounce message back, there is no diagnostic code, no nothing. i know the email address is valid, i know DNS is working (i ran dig on the domain to get the MX record, etc etc, everything looks fine)

Can somone point me in the right direction? where to look? what to try next?

Any help would be greatly appreciated.

Cheers!

[uxbod]

Are you using a internal or external DNS for resolution ?

[cadman]

External DNS

[uxbod]

Sounds like a timeout. Could you build a caching DNS on your ZCS server ?

[cadman]

the probem i mention above tho, is that it is repeatable, meaning, it happens for to_addr@zzz.com every time, not just spontaniously. i would think that wasnt a timeout issue, or am i wrong?

[uxbod]

Would you check /opt/zimbra/log/mailbox.log aswell and see if any error messages are present for that particular mailbox ?