[ On Wednesday, July 6, 2005 at 17:55:57 (+0200), Elmar Leirich, CONCEPTNET GmbH wrote: ]
> Subject: [exim] Performance Problem
>
> I have Debian running with Exim4 on a Athlon XP 1800 Server with 1GB Ram.
> Spamassassin and Clamav are installed. I use Vexim/Mysql for handling
> virtual domains.
>
> When I try to send a small Text Message, it takes about 3-5 Seconds before
> the Mail is sent by Outlook. A Message with an Attachment of about 6MB takes
> about 10-15 Seconds sometimes up to 30 Seconds before the Mail is fully sent
> to the mailserver and Outlook "sees" the message as sent.
Have you run a timestamped TCP trace on such a connection so that you
can see exactly where the delays are? (use tcpdump, ethreal, etc.)
Is there any kind of Anti-Virus software active on the client system?
It is quite common for client-based AV software to do the effective
equivalent of pausing/stoping the client software while it scans the
outgoing message(s) in the client's queue. Some such AV software takes
an extremely long time to run on larger messages, even on beefy client
hosts. You should see this pause in the packet trace.
Some such AV software even reveals its presence by grabbing the socket
handle from the client and sending RSET (a stupid abuse of RSET) or NOOP
commands every 5 seconds (stupidly abusive) to 30 seconds (not quite so
aggressively stupid though still excessive since the server timeout
should be a minimum of 5 _minutes_ :-) to be sure that the server
doesn't timeout and drop the connection while it takes its time scanning
the outgoing message.
> I have
> outcommented the "host_lookup" option
If your reverse DNS is functioning properly for that client then that
shoudln't matter.
> and I disabled Ident.
If your client has nothing listening on the IDENT port than that won't
matter either.
--
Greg A. Woods
H:+1 416 218-0098 W:+1 416 489-5852 x122 VE3TCP RoboHack <woods@???>
Planix, Inc. <woods@???> Secrets of the Weird <woods@???>
