Re: [Exim] Advice - Building mail platform from scratch

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Author: Bruce Richardson
Date:  
To: Exim Users
Subject: Re: [Exim] Advice - Building mail platform from scratch
On Wed, May 12, 2004 at 11:43:37PM +1200, Ray Jackson wrote:
> 1. Anti-spam: SpamAssassin vs. DSPAM? (or something else?)


I haven't evaluated DSPAM itself but I would warn you not to trust some
of the very silly things the developer says while slating the
competition in his documentation. This doesn't say anything about DSPAM
as an application, it just makes his judgement a little questionable.

> 2. Anti-Virus:  Which engine (we are looking at Sophos Sweep)
>                 and do I use Amavis or Exiscan (or something else?)
>                 If I choose Sophos - do I use Sophie?


The greate advantage of using Exiscan to do your anti-virus checking is
that it allows you to reject viruses at the smtp conversation stage.
Done properly, this drastically reduces the number of spurious NDRs that
you generate, for one thing.

There are issues to be aware of with this approach: load and timeouts,
mostly. You may want to have the virus scanner (e.g. clamav) listening
on a dedicated host. You might also consider only scanning messages
under a certain size (maybe 20K) with Exiscan and sending messages over
that size through a more conventional filter: this avoids the danger of
timeouts caused by scanning very large messages (and since viruses in
documents over that size are quite rare, spurious NDRs are still not
much of a risk).

--
Bruce

Nostalgia isn't what it used to be.