Joined: 18 Dec 2005
|Posted: Mon Jun 03, 2013 8:27 am Post subject: smtp server timeout
Some mail servers are trying to deliver to a gentoo qmail server in my LAN but they are experiencing problems.
Basically, there's a timeout (see below). Other SMTP servers seem to deliver their email just fine.
What I've noticed from the log below is that there's a delay of 1 minute from the moment smtp.domain.com first shows up until my mail server (mail.mydomain.com) replies. Could this cause the sending server to consider the SMTP transaction as timed out thus not proceeding with the usual SMTP commands? (of course, mail.mydomain.com also drops the connection after 5 minutes since it's not getting anything from smtp.domain.com).
2013-06-03 09:29:10 pid 21197 from XXX.XXX.XXX.XXX
2013-06-03 09:29:10 ok 21197 :::ffff:10.215.144.7:25 smtp.domain.com:::ffff:XXX.XXX.XXX.XXX::6048
2013-06-03 09:30:13 21197 > 220 mail.mydomain.com ESMTP
2013-06-03 09:35:13 21197 > 451 timeout (#4.4.2)
2013-06-03 09:35:13 21197 > [EOF]
2013-06-03 09:35:13 end 21197 status 256
[EDIT] Shouldn't mail.mydomain.com greet smtp.domain.com as soon as it receives the SMTP connection? In the above example, shouldn't "220 mail.mydomain.com ESMTP" be occurring about 1 minute earlier? If so, what could be happening? Is it something wrong with mail.mydomain.com or with smtp.domain.com? Could it be due to some kind of DNS lookup delay or RBL list lookup delay, etc?