Meanwhile I was able to dig for the root cause togetrher with ["johannes"] and found:
my mail provider (GMX) refuses to accept the mail from the forum's mail-server. The reason seems to be that here in Germany at least GMX and WEB.de perform a "reverse DNS lookup" (https://en.wikipedia.org/wiki/Reverse_DNS_lookup) for the delivering server to reduce spam load (and in fact it is efficient). The forum server logs following:
I have checked the header of such a mail which carries a local IP address for the sender of forum mail.Jul 24 08:30:37 public postfix/smtp: 9226E9868D: host
mx00.gmx.net[220.127.116.11] refused to talk to me: 554-gmx.net (mxgmx010)
Nemesis ESMTP Service not available 554-No SMTP service 554 invalid DNS
PTR resource record
I digged out an old notification from May 2012 where Exito's mail server
was different and all worked fine. Here the important part form that
.... snip ....
Received: (qmail invoked by alias); 08 May 2012 07:35:54 -0000
Received: from mail.excito.net (EHLO excitohb.cust.ipeer.se)
by mx0.gmx.net (mx025) with SMTP; 08 May 2012 09:35:54 +0200
Received: from excitohb.cust.ipeer.se (localhost.localdomain [127.0.0.1])
by excitohb.cust.ipeer.se (Postfix) with ESMTP id 12A4C3A21624
for <firstname.lastname@example.org>; Tue, 8 May 2012 09:35:52 +0200 (CEST)
...... snip ........
And now you can clearly see the sender is:
"mail.excito.net" with IP = 18.104.22.168.
Checking the reverse DNS lookup:
Code: Select all
dig PTR -x 22.214.171.124
So at that time all was fine and now it fails because of 2 things:
1. forum's mail server has a private/local IP address
2. IP and hostname do not match and cannot be reverse resolved.
So I wonder if I (with GMX and/or WEB.de as mail provider) am the only one not receiving mails from the forum anymore???
This can only be solved by Exito by delivering the mails though an officially approved mail server.