Few general questions regarding MailScanner

[Jim Holland]

Hi

On Fri, 5 Mar 2004, Jason Williams wrote:

> >Drawbacks:
> >         Mailscanner - double queuing means extra disk IO. Unable to do
> >SMTP rejects.

I thought that this was going to be a major drawback, as we have
previously been using a dnsbl that blocked at the SMTP level and I liked
the fact that it meant the spammers were told we were a no-go area.
However the effect of that was not to make them go away, but just to try
harder - they would try sending the same message from numerous different
servers.  So the disadvantage in wasting bandwidth by accepting spam is
partially overcome by the advantage that the spammers don't make numerous
attempts to send the same message in order to try to force it through.

The fact that spam is quarantined also offers the benefit that a more
aggressive level of blocking can be used knowing that the recipients can
still ask for mail to be released if genuine mail has been blocked.  This
does assume that there is a system of notification to users - we do this
with a single daily compilation of blocked messages.

Finally - there is nothing to stop you continuing to block at the SMTP
level using the facilities of your MTA (eg the access file if you use
sendmail).

Regards

Jim Holland
System Administrator
MANGO - Zimbabwe's non-profit e-mail service