Need advice on new mailserver and spam

[Mike Klinke]

On Monday 06 June 2005 10:22, Bob Brennan wrote:
> I've been called in to solve some massive email problems in a
> company that has about 30 employees and an external mailserver.
> They receive on average about 100 legitimate emails per day and
> 3000+ spams plus the usual virus and worm attacks.
>
......

> My question is - long term - is it better to set up the
> mailserver to reject all non-mailbox emails to cut down on the
> incoming processing load; or to filter and bit-bucket the spam in
> the hopes that the volume will decrease over time with no
> responses to the spam? Or any other techniques any of you are
> using for such problems?
>
> Thanks in advance for opinions/suggestions,
> bob

Take a serious look at greylisting.  I suspect that you can reduce 
your spam load to almost insignificant proportions with that alone.

Here is a good description of the technique:

  http://projects.puremagic.com/greylisting/whitepaper.html

and a  particular implementation I have used to good effect:

  http://hcpnet.free.fr/milter-greylist/


Regards, Mike Klinke