SMTP Filter

[David Nugent <davidn@unique.blaze.net.au>]

Is there any way with the current smtpserver to achieve
some sort of filtering on mail based on any one or all of:

  1) Remote host IP and/or resolved hostname
  2) Sender
  3) Recipient

Doing this seems to be the only reasonable and
cost-effective way of filtering out the commercial trashmail
that some specific sites seem to be in the business of
filling mailboxes with. Once an email address gets into
circulation (it seems that a single post to news will
sometimes do it), it seems to attract a considerable number
of junk-mail items over the next few months. Since we pay
for inbound traffic, and over the last number of months the
volume of this sort of junk-mail is now starting to become
significant in terms of cost, I'd ideally like to be able to
filter it out and reject such items before it is actually
transmitted.

I realise that this is not a final or ideal solution to the
problem, but it would go a long way towards reducing our
contribution to the coffers of a few thoughtless "fast cash"
companies around the world who indulge in these sort of
dubious practices.


David Nugent, Microsystems Technical Support
Unique Computing Pty Limited, Melbourne, Australia
PC/LAN/UNIX Communications Software Development