I have big problem - I have a server that was just upgraded to 6.0.6 due to the issue with clamd updates. Prior to the upgrade everything was working just fine.

The issue is: emails are using the primary account information for the RCPT field - not the info stored in the prefs/Accounts/Primary or external account when sending mail.

Currently the server is deferring mail to hosts that reject the mail from non dns verifiable hosts - like they should

User - abc
(abc@domain.com is an alias for user@city.domain.com)
Primary account: abc@city.domain.com
Mail From set to abc@domain.com ( account prefs)
Reply To set to abc@domain.com (account prefs)

External account: abc@domain.com
Mail From set to abc@domain.com ( account prefs)
Reply To set to abc@domain.com (account prefs)

MY Server (the server receiving the mail) shows the following for the inbound msg:
Apr 21 18:29:35 mail postfix/smtpd[13053]: NOQUEUE: reject: RCPT from 66-255.255-198.ds1-static.mia1.net:
450 4.1.8 <abc@delray.domain.com>: Sender address rejected: Domain not found; from=<abc@delray.domain.com> to=<bobm@windward-dev.com> proto=ESMTP helo=<mail2.domain.com>

[ notice the RCPT is wrong it should be the value in the Account Prefs]
[also - the helo is set to mail2.domain.com, this is correct - and that host does have a DNS A record]

what gets me is that when I check the users Sent folder and examine the original message I get:
Date: Wed, 21 Apr 2010 18:23:45 -0500 (GMT-05:00)
From: Scott <abc@domain.com>
Reply-To: Scott <abc@domain.com>
To: Scott <abc@domain.com>,Bob Masterson <bobm@windward-dev.com>

BTW - the reason for this convoluted setup is that the client insisted continuing to use a third party to host corp mail - So we send out local mail, and pop the corp server for inbound mail.

as a quick fix I'm trying to get the powers that be to add a DNS record for city.domain.com just to buy some time, but this should not be happening the account pref vaules are not being used when the mail is actually being sentand all was fine prior to the upgrade.

Any thoughts would be welcome -