Postfix Address Verification

Seamus Allan seamus at
Fri Jun 29 04:57:31 IST 2007

Drew Marshall wrote:
> On Wed, June 27, 2007 23:46, Seamus Allan wrote:
>> It seems after implementing this that I am having a lot of spam stopped
>> at MTA level - this is very good.<br>
>> However, the next morning I came in to discover that some of the
>> domains we host were not getting any email.<br>
>> I used telnet to pretend to have a fake session with the smtp server,
>> and interestingly, when trying to do a rcpt <a
>> class="moz-txt-link-abbreviated"
>> href="mailto:to:user at">to:user at</a>, I
>> get the following error message.<br>
>> 450 <a class="moz-txt-link-rfc2396E"
>> href="mailto:user at">&lt;user at;</a>:
>> Recipient address rejected: Domain
>> not found<br>
>> Why is this happening? How come that Postfix is able to look into the
>> transport map and check the next server in line to see whether the user
>> is valid for most of the domains, but not for some. Is there a
>> misconfiguration somewhere? Is the verify map full or something?<br>
> Firstly, please could you not use HTML mail. It does become something of a
> mess (As you can see above) when working in plain text.
I even made a point of not top posting. Guess I can't make *everyone* happy.
> Anyway, check your maillog as I would expect the domain not found error to
> come from a Postfix client access restriction (Reject unknown sender
> domain for example) and nothing to do with your recipient maps. The logs
> will tell you more.
> Drew
I spent the good part of a day investigating logs and found almost 
nothing useful. I was expecting to see a point where the main (hub) 
mailserver started rejecting the (Mailscanner) Gateways probes to check 
whether a mailbox existed, as the probes are only Helo, Mail from, rcpt 
to, then a disconnect.

Anywho, here are some log snippets for you to gander at.

This is for a domain where is worked:
Jun 28 02:49:24 gatekeeper2 postfix/smtpd[8702]: NOQUEUE: reject: RCPT 
from[]: 550 <user at>: 
Recipient address rejected: undeliverable address: host[] said: 550 Requested action not taken: 
mailbox unavailable or not local (in reply to RCPT TO command); 
from=<agassy at> to=<user at> proto=SMTP 

And this is for one where is didn't:
Jun 28 02:49:28 gatekeeper2 postfix/smtpd[8700]: NOQUEUE: reject: RCPT 
from unknown[]: 450 <user at>: Recipient address 
rejected: Domain not found; from=<jahka at> 
to=<user at> proto=ESMTP helo=<>

After scouring the logs on both the gateway machine and the mail hub and 
can't seem to find anything useful.

Any ideas?



*Seamus Allan*
Network Engineer
Rheel Electronics Ltd
Phone +64-3-386 3070 Fax +64-3-386-3071
Mobile +64-21-178-2980
seamus at

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