| Re: Random Failed Connection on Port 25 from CSS Keep-Alive |
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Group: comp.mail.sendmail · Group Profile
Author: Andrzej Adam FilipAndrzej Adam Filip Date: Mar 13, 2008 06:17
sunckell gmail.com> wrote:
> Got a Strange one here.
>
> We are running Sendmail 8.13.8+Sun/8.13.8 on a fully patched
> Solaris 10 server. Some business users wanted notifications if
> sendmail were to stop responding.
>
> So we added a Keep-alive to our
> CSS, all it does is connects to the port issues a helo and looks for a
> 250 in return. This runs every 5 secs. If it can't connect to the
> port or does not receive a 250 response, it marks it down and
> notifies.
How long does you wait for the greeting?
In some *super nasty* cases involving "out of date aliases" it could
take up to 10 minutes to get the greeting. Making test script wait
*at least* 2 minutes is a sensible minimum.
Do you record "time to greeting"?
> We added this last Friday, and since then we are seeing several
> "failures". The strange part is, the service is still running, there
> is nothing odd in the logs, except you don't see the CSS connects
> during the time period the CSS sees the port as down (or any other
> traffic for that matter.)
>
> We have seen time gaps in the logs up to 40 secs.
> We have snooped the traffic and everything appears to be correct,
> (from an ACK/SYN/FIN) standpoint.
Have you ruled out short DNS resolution problems?
40s gaps may be caused by it.
Have you tried to correlate gaps with updates of aliases?
> [...]
> I am hoping someone else out there has experience in troubleshooting
> this sort of issue and can give me some suggestions.
--
[pl>en: Andrew] Andrzej Adam Filip : anfi@priv.onet.pl : anfi@xl.wp.pl
Open-Sendmail: http://open-sendmail.sourceforge.net/
"We have the right to survive!"
"Not by killing others."
-- Deela and Kirk, "Wink of An Eye", stardate 5710.5
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