Re: [Exim] lots of processes

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Author: Philip Hazel
Date:  
To: Randy Mingo
CC: exim-users
Subject: Re: [Exim] lots of processes
On Wed, 8 Oct 2003, Randy Mingo wrote:

> We've been having some strange happenings with exim lately. We use
> postini.com as a filtering system for spam and virus' so they clean
> the email then deliver it to us. On a fresh reboot the machine will
> run fine for a hour. Then right at the hour mark the processes start
> climbing and keep climbing until the machine dies. It looks to us as
> if the people who spam check our email are making connections that do
> nothing and never let go. Is there any settings we might be able to
> tweak to make it drop their connection after a set period of time.


You don't say which version of Exim you are using. This reply applies to
the current release (4.24).

There are timeouts on incoming SMTP connections. However, if a client
just sits there and, for example, sends NOOP or RSET every 4 minutes,
they can hold a connection for a long time.

Exim does have a defence against this. Check out the
smtp_accept_max_nonmail option (introduced in Exim 4.11). You should
also consider setting

log_selector = +smtp_connection

That will make Exim log when each connection starts and when it ends.

--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book