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: > On 9/30/2011 10:49 AM, ajm wrote: >> 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=<x...@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? >> >> > > The server at 213.146.196.92 is refusing your mail; only they can > 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
