CentOS - May 2006 - Sendmail burst of "rejecting connections" - why?

What's the reason for the burst of sendmail complaints below?

My CentOS 4.3 server only handles internal mail for my small network.
It doesn't handle Internet mail at all, so I guess I can't blame a
crack attempt for this.  IPTables rules should prevent external
connections to everything except SSH's port 22.

I've looked through the other logs hoping that some other activity would
be seen at this time as well.  Nothing.  the surrounding entries in
/var/log/maillog are perfectly reasonable.  As far as I can tell this
14-minute burst of sendmail activity exists in isolation.

Can anyone suggest a reason for these log entries?

Thanks.

-------------------------------------------------

May 25 07:09:24 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 24
May 25 07:09:39 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 25
May 25 07:09:54 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 26
May 25 07:10:09 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 29
May 25 07:10:24 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 31
May 25 07:10:39 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 32
May 25 07:10:54 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 33
May 25 07:11:24 server last message repeated 2 times
May 25 07:11:39 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 34
May 25 07:12:24 server last message repeated 3 times
May 25 07:12:39 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 34
May 25 07:12:54 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 33
May 25 07:13:09 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 32
May 25 07:13:24 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 31
May 25 07:13:54 server last message repeated 2 times
May 25 07:14:09 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 30
May 25 07:14:54 server last message repeated 3 times
May 25 07:15:25 server last message repeated 2 times
May 25 07:15:40 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 29
May 25 07:15:55 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 29
May 25 07:16:10 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 28
May 25 07:16:25 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 27
May 25 07:16:40 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 26
May 25 07:16:55 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 25
May 25 07:17:10 server sendmail[2942]: accepting connections again for daemon
MTA
May 25 07:17:45 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 24
May 25 07:18:00 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 25
May 25 07:18:15 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 27
May 25 07:18:30 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 28
May 25 07:18:45 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 29
May 25 07:19:00 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 30
May 25 07:19:45 server last message repeated 3 times
May 25 07:20:00 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 29
May 25 07:20:15 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 28
May 25 07:20:45 server last message repeated 2 times
May 25 07:21:00 server sendmail[2942]: rejecting connections on daemon MTA: load
average: 25
May 25 07:21:15 server sendmail[2942]: accepting connections again for daemon
MTA

Steve Snyder wrote:
> 
> -------------------------------------------------
> 
> May 25 07:09:24 server sendmail[2942]: rejecting connections on daemon MTA:
load average: 24
> May 25 07:09:39 server sendmail[2942]: rejecting connections on daemon MTA:
load average: 25
system loads > 20 are not normal, try running 'sar' over a period of
time to figure out whats going on, are you seeing very high iowait or it
could even be d-state proc's causing this high load.

your solution to the issue is going to be working out what / why such a
high load is being reported.

- KB
-- 
Karanbir Singh : http://www.karan.org/ : 2522219 at icq

On Friday 26 May 2006 7:15 am, Steve Snyder wrote:
> What's the reason for the burst of sendmail complaints below?
[snip]

Several people (thanks, guys!) explained the situation to me.  I thought 
that it was Sendmail itself that was experiencing the high load, which 
shouldn't ever happen.  The real story is that it was the system that was 
experiencing the high load.

The cause of the system high load is no mystery.  I was doing a "make
-j3"
kernel build around that time, so there was high CPU and disk 
utilization.  I wasn't aware when I posted my question that Sendmail 
monitors system load.

Thanks.

On Fri, 2006-05-26 at 06:15, Steve Snyder wrote:
> What's the reason for the burst of sendmail complaints below?
> I've looked through the other logs hoping that some other activity
would
> be seen at this time as well.  Nothing.  the surrounding entries in
> /var/log/maillog are perfectly reasonable.  As far as I can tell this
> 14-minute burst of sendmail activity exists in isolation.
> 
> Can anyone suggest a reason for these log entries?
> 
> Thanks.
> 
> -------------------------------------------------
> 
> May 25 07:09:24 server sendmail[2942]: rejecting connections on daemon MTA:
load average: 24
This doesn't mean sendmail is busy, it means sendmail has noticed
that the machine is busy doing other things and since mail
will be queued and retried, it stops processing any until
the load goes down.   You might check your cron entries to
see if anything else is started around the time in question
to explain the load - or it could have been programs you
were running at the console.

-- 
  Les Mikesell
   lesmikesell at gmail.com