MTA preferences for use with MailScanner

[Richard Bourque]

On Fri, 30 Jul 2004 03:33:12 +0100, Julian Field
<mailscanner at ECS.SOTON.AC.UK> wrote:

>At 15:45 29/07/2004, you wrote:
>>Allow me to paste fro the Postfix archives:
>>------------
>>MailScanner does its work by grabbing files out of the queue, runs its
>>processing, and drops the resulting file back into another postfix
>>queue.  This is not a documented method to perform content filtering in
>>postfix.
>
>It's not documented in Exim either. But the guys who wrote Exim run
>MailScanner. The sendmail guys just did the honourable thing and documented
>the whole process, they have nothing to hide.
>
>>The problem is that there is no reliable way for a non-postfix program to
>>determine when it's safe to grab the queue file.  So it's never safe for an
>>external program to grab a queue file when postfix is running.
>
>So Postfix does a secret-squirrel handshake or something? It's code, it's
>deterministic.
>
>>So MailScanner will randomly grab an incomplete file,
>
>Simply not true.
>
>>  resulting in loss of
>>a random portion of that message,
>
>Also not true.
>
>>  with no warning and no indication that
>>part of the message was lost.
>
>Also not true.
>
>>   Apparently it *usually* works, but you can't
>>tell when it doesn't.  Software that by design *usually* works is not
>>acceptable.
>
>Except when *usually* = 100%.
>
>>Therefore, MailScanner is unreliable with postfix.  This does not offer an
>>opinion about MailScanner with other MTAs, only postfix.
>
>I'm sorry, I thought "outside the box". Please accept my apologies for not
>using your (relatively slow) "approved" way of doing things, and coming up
>with a novel idea you didn't think of.
>
>>If you want to use MailScanner, don't use postfix.
>
>There are plenty of faster MTA's out there, such as Exim or ZMailer, so I
>would personally agree with this statement. But not for the same reasons
>they are saying it.
>
>>   If you want to use
>>postfix, choose a different content filtering method, there are several
>>documented filtering methods and many reliable third-party products to
>>chose from that work properly with postfix.
>>------------
>>
>>However, it works for me, so what can I say.
>
>Precisely.
>
>As you may have gathered, there is no love lost between me and Wietse. But
>then again, from what I have heard from some of his previous colleagues,
>I'm not the only person in that situation :-)
>--
>Julian Field

<snip>

After reading some of Weitz's comments about MailScanner 6-7 months ago I
dumped a perfectly working Postfix/MailScanner installation and switched to
Exim/MailScanner, even though it has been running for almost a year without
a single problem.

I made the change on principle.  I feel safer using Exim because I get the
impression Philip Hazel would assist Julian (and vice versa) if there ever
were any problems, but I feel Weitz doesn't want any 3rd party apps to work
with Postfix at all and would hinder development as a whole for the MTA
community.

Just my two cents worth.

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