Problem with "temporary failure at return MX check"
ajm
Hello!
I recently installed a new mail server with postfix 2.8.2. This machine replaced an older one, with nearly the same features and configurations.
Since that, however, I'm experimenting problems to send emails to only one destination. Logs show:
Sep 28 18:51:27 mailserver postfix/smtp[21279]: 3418C61EE1: enabling PIX workarounds: disable_esmtp delay_dotcrlf for oa.pt[213.146.196.92]:25
Sep 28 18:51:47 mailserver postfix/smtp[21279]: 3418C61EE1: to=<XX...@adv.oa.pt>, relay=oa.pt[213.146.196.92]:25, delay=3207, delays=3167/0/20/20, dsn=4.0.0, status=deferred (host oa.pt[213.146.196.92] said: 421 DNS temporary failure at return MX check, try again later (#4.3.0) (in reply to MAIL FROM command))
I started checking for DNS problems. Everything seems to be correct, both A and MX records, as well as reverse resolution.
I already tried to disable pix workarounds, as older version didn't have this feature and worked well, but there were no changes in results. Can somebody please help me on this subject?
Thank you!
Antonio
Noel Jones
give you an authoritative answer why.
From the message returned, I assume they are doing an MX lookup on
the MAIL FROM domain, and that lookup fails. This doesn't have
anything to do with the pix workarounds.
-- Noel Jones
ajm
If pix workarounds are out of question, I think just DNS remains.
On DNS I have currently:
nslookup -query=MX domain - returns only an MX_server - the correct one
nslookup MX_server - returns the correct ip address
nslookup ip_address - returns the name of a machine from the same
domain, but not the MX_server.
Even if the reverse resolution does not point to exactly the same name
(there are CNAMEs), it resolves to the same domain.
I thought it would be enough, as I did never need more than this before,
but then this is probably the problem.
Thank you for your help!
On Fri, 30 Sep 2011 11:15:07 -0500, Noel Jones <njo...@megan.vbhcs.org>
wrote:
Robert Schetterer
use dig for lookups
better with real world examples
mx entries in dns are no secrets
after all i think your question was allready answered by Noel
--
Best Regards
MfG Robert Schetterer
Germany/Munich/Bavaria
Noel Jones
On 9/30/2011 11:23 AM, ajm wrote:
>
>
> If pix workarounds are out of question, I think just DNS remains.
>
> On DNS I have currently:
>
> nslookup -query=MX domain - returns only an MX_server - the correct one
> nslookup MX_server - returns the correct ip address
> nslookup ip_address - returns the name of a machine from the same
> domain, but not the MX_server.
lookups work for you doesn't mean they work for everyone.
>
> Even if the reverse resolution does not point to exactly the same name
> (there are CNAMEs), it resolves to the same domain.
> I thought it would be enough, as I did never need more than this before,
> but then this is probably the problem.
enough.
-- Noel Jones