450 + Sender address rejected: Domain not found + (in reply to RCPT TO command)

[fyd]

Please don't feel its just another thread on this topic I did search forums and stuffs, learned a bit but still its not clear why a mail is rejected saying sender address rejected, and domain not found. It is a local account in my server and a real one.

Jan 19 10:27:46 postfix/smtpd[24022]: 6A6461488403: client=localhost.localdomain[127.0.0.1]
Jan 19 10:27:46 postfix/cleanup[24161]: 6A6461488403: message-id=<725609724.510040.1295429086293.JavaMail.root@x xxx>
Jan 19 10:27:46 postfix/qmgr[19098]: 6A6461488403: from=<myacc@domain>, size=38495, nrcpt=1 (queue active)
Jan 19 10:27:46 amavis[21010]: (21010-01-34) FWD via SMTP: <myacc@domain> -> <acco@domain>,BODY=7BIT 250 2.0.0 Ok, id=21010-01-34, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 6A6461488403
Jan 19 10:27:46 amavis[21010]: (21010-01-34) Passed CLEAN, [xx.xx.xx.xx] <myacc@domain> -> <acco@domain>, Message-ID: <725609724.510040.1295429086293.JavaMail.root@xxxx x>, mail_id: xwItztyOQ6jl, Hits: -6.899, size: 38056, queued_as: 6A6461488403, 904 ms
Jan 19 10:27:46 postfix/smtp[24125]: 51BC4148840F: to=<acco@domain>, relay=127.0.0.1[127.0.0.1]:10024, conn_use=34, delay=180, delays=0.01/179/0/0.91, dsn=2.0.0, status=sent (250 2.0.0 Ok, id=21010-01-34, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 6A6461488403)
Jan 19 10:27:51 postfix/smtp[19061]: 6A6461488403: host mx.domain.com[xxx.xxxx.xxx.xx] said: 450 <myacc@domain>: Sender address rejected: Domain not found; [id:B7/3F-12863-39EA63D4] (in reply to RCPT TO command)

Reply to my 'RCPT TO' message as part of smtp ack is returned with the destination server saying 'sender address rejected and domain not found'. I understand this sender address is my acc and how does it end up in that conclusion?

My acc is not an external account. I don't think there is a dns problem since mail delivery is normal with other accounts. And my domain is properly resolving with proper MX and A records.

Can anyone guide me here?

[phoenix]

I'll always start with the obvious request, go to the Split DNS article and post the output from all the commands in the 'Verify...' section.

Has this just started happening or is it a new problem? Are these emails sent via the web UI and are both of the accounts local to your LAN?

[fyd]

Hi Bill, I will carry out the tests. It just started happening for this account, I don't think other accounts face this problem. So that is what puzzles me.

I believe they are sent via web UI. The destination account is not local to my lan, it is an external MX.

But can you please state the summary of the log? My assumption is the mail is actually going out and reaching the receipient end, and rejected back. If there is a dns issue, it probably wouldn't be leaving my server right? Thanks Bill, for helping like always.

[phoenix]

Originally Posted by fyd

I believe they are sent via web UI. The destination account is not local to my lan, it is an external MX..

Sorry, I saw the 'local account' in your first post and made the assumption that this was being sent between local users.

You're quite right about a DNS problem, if this recipient is not on your server then the likelihood is that there's a DNS problem somewhere. I was slightly misled by the fact you've commented out the domain name and IP address for the receiving server (again, I thought that was your server). The simple test would be to do a dig for the recipient domain name, you could also try connecting to the server via telnet and try sending an email to the user by using the command line.

If you don't know how to use telnet to test a remote SMTP connection then here's a few examples (you could practice on your own Zimbra server first so you don't cause any problems at the remote server): +telnet +"test smtp" +command +line - Yahoo! Search Results

[fyd]

Okay I will do that. So to sum up, I assume my RCPT message reach the destination(propogation till there is fine), and this destination MX's local DNS setup could be messed up. It looks up, fails( says domain not found) and cannot acknowledge the RCPT signal. I guess I am good with that thinking.

My deferred queue pretty neat, so that was why I was confident about DNS thing. Thanks a bunch Bill ..