sendmail queue question

[Roger Oberholtzer]

On Wed, 2009-10-07 at 13:53 -0500, David A. Bandel wrote:
> On Wed, Oct 7, 2009 at 10:45, Roger Oberholtzer <roger at opq.se> wrote:
> >
> > Is there any logic in sendmail to delay sending mail to some hosts? I
> > have a situation where mail arrives to a mail host running sendmail, and
> > the mail sits there for over 45 minutes before being sent on. I think it
> > is only for some destinations. The destination in question is a local
> > internal machine. It is available, and  the DNS is responding promptly.
> > I am at a bit of a loss where to look. sendmail -bh for the hosts says:
> >
> >  acme.pacific               00:04:53 250 2.0.0 Ok: queued as 1
> >
> > So why does mail to this system sit around for 45 minutes?
> 
> Roger,
> 
> Sendmail will by default deliver immediately any mail that is
> immediately deliverable.  That is, it will try not to create a queue.
> However, if sending to a host fails (for whatever reason), it will
> create the spool file and wait the -q <interval> time to resend.
> 
> So apparently, for some reason your other mail server either isn't
> available, isn't accepting mail, or is temporarily rejecting mail.
> Either way, the problem is not sendmail.  Check your other server's
> logs (and the sendmail logs as well -- usually /var/log/mail.log).

I have looked at this, and am still confused. The sender logs claim that
the receiver refused the connection. I do not see a failed attempt in
the receive logs. Then, the message is queued on the sender, who seems
to empty the queue at 51 minutes past each hour. So, at 51 minutes past
the hour, the receiver gets a bunch of mail.

I do not know why the sender feels the connection is refused. I can
connect by hand to the smtp server on the receiver. And, why would the
connection always work in the queue, but not in the initial sending?

I have restarted the mail system on both. I have reset the hosts stats
(sendmail -bH, IIRC). 

-- 
Roger Oberholtzer

OPQ Systems / Ramböll RST

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden

Office: Int +46 8-615 60 20
Mobile: Int +46 70-815 1696