Michael,
> MailScanner is - and always has been - just a dirty hack. It sure has
> developed over the years and great efforts are still put into it. So it is
> constantly maturing and improving. However, it's still a dirty hack.
>
> All the MailScanner scripts that wrap around Sendmail have a tendency of
> being
> a bit spooky and can indeed loose mails, attachments or other bits and
> pieces. Espececially under high load it can be that processes related to
> MailScanner run out of memory and/or crash. What then happens with the
> email
> being processed depends on what stage of delivery MailScanner currently
> was.
> At best the mail is still in the queue, being processed again sometime
> down
> the road. At the worst? The mail gets lost, garbled or truncated.
>
> So under high load MailScanner may go awry on you. On the other hand:
> MailScanner is so ineffective, that it'll drive the load right through the
> roof even under moderate email traffic.
>
> I just had the pleasure of looking at a server that was using MailScanner
> and
> which processes roughly 100.000-150.000 emails a day. It was constantly
> hovering around 6.80 and 8.50 server load - even with Syslogd shut down to
> save CPU cycles during the cron.daily cron runs.
>
> The same server is now running something different which provides equal
> (or
> better) protection, uses Sendmail Milter to tie the virus and spam
> checking
> into the MTA and the box processes the same amount of emails as before.
> The
> load? It's down to a 15 minute load average of 0.18. With logging turned
> back
> on.
>
> My suggestion therefore: Get rid of MailScanner. I don't have half as much
> experience with Postfix in regards to customizations as with Sendmail, but
> newer versions of Postfix also support Sendmail style Milters as it
> appears:
>
> http://wiki.linuxquestions.org/wiki/Postfix_with_clamav-milter
>
> So you can install Clam AV Milter and possibly also SpamAssassin Milter
> (there
> are a few Milters for SpamAssassin available).
>
> Of course there is also the somewhat more traditional approach of
> integrating
> Clam AV and SpamAssassin into Postfix - without Milters:
>
> http://www.tedesca.net/bez/homeoff/antispam.html
>
> Any of the above approaches is certainly better than using MailScanner.
> Just
> my $0.02.
>
> --
> With best regards,
>
> Michael Stauber
> http://www.solarspeed.net
Thanks for your input. I'd like to make it clear that we are not using
Postfix. It was the fact there was such controversy between Postfix and
MailScanner, that we were concerned that problems between those packages
could be happening in our situation. We are running MSI servers with the
Nuonce BlueQuartz install with all the purchased packages pre-installed
(MailScanner, ClamAV, SpamAssassin, etc.). I guess, in your view, this
seems highly likely and I would have to agree.
We have been running a considerable number of months, without any issues.
This just came up on Monday. We hadn't done any server updates, there were
no process changes made, this just seemed to go awry. Our volume is
considerably less than the 100K to 150K message volume you indicated. We are
in the 20K messages a day range. However, I can definitely see your point
about how load can be a factor. While we don't have high volume in terms of
messages sent, we do experience our email in spurts. We could go awhile
where the messages trickle in, and all of the sudden get a flood of a few
hundred to a few thousand. So, performance issues could be playing into
this.
Unfortunately, I am not anywhere near versed in Sendmail to know where we
could cut MailScanner out and use milters to replace the same functionality.
I guess it's time to hit he 'net and start digging.
Thanks again
Ernie
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