[CentOS] Sendmail problem - baffled

Tue May 15 20:22:09 UTC 2012
Alexander Dalloz <ad+lists at uni-x.org>

Am 15.05.2012 21:44, schrieb Jussi Hirvi:
> Our backup mail server (which I have just re-configured) tries to 
> contact the primary mail server, and fails. My log shows repeatedly 
> "connection refused":
> 
> May 15 22:21:41 mx2 sm-mta-rx[8674]: q4FIhPij007483: makeconnection 
> (mail.greenspot.fi. [83.143.217.182]) failed: Connection refused by 
> mail.greenspot.fi.
> May 15 22:21:41 mx2 sm-mta-rx[8674]: q4FIhPij007483: 
> to=<myuser at mydomain.com>, delay=00:38:16, xdelay=00:00:00, mailer=esmtp, 
> pri=10021795, relay=mail.greenspot.fi. [83.143.217.182], dsn=4.0.0, 
> stat=Deferred: Connection refused by mail.greenspot.fi.
> 
> But yet I can successfully telnet that host:
> 
> # telnet mail.greenspot.fi 25
> Trying 83.143.217.182...
> Connected to mail.greenspot.fi (83.143.217.182).
> Escape character is '^]'.
> 220 mail.greenspot.fi ESMTP Sendmail; Tue, 15 May 2012 22:34:22 +0300

It is technically impossible that the telnet to target port 25 succeeds
from the same system on which the Sendmail gets a connection refused,
unless Sendmail is configured to use a non-standard target port.

> Also, the mailer-daemon *can* send automatic warning messages to 
> mail.greenspot.fi just fine.
> 
> So, the error probably is in my sendmail configuration.
> 
> The error appeared as I today reconfigured the backup mail server to use 
> a "dual sendmail" setup with amavis and greylisting. How could I proceed?

Deeply inspect your sendmail.mc files. Provide them here if you like to
get assistance.

> - Jussi

Alexander