Here is our current configuration from a "big picture" point of view... We have a unix box as a name server and a sendmail server. What happens, is mail is sent to the unix box, then to an NT4 server running domino then to another NT4 server running domino as well. We currently have no spam filter what-so-ever, and I'm looking into implementing something which rids at least 75% of spam and garbage email at the server level of course. I've looked at spamassassin somewhat and it looks like it will do the job, I guess my next step is implementation, which is why I'm here.
Basically, I'm looking for advice; not like- "oh you should just use this..". I mean like- "you have to install x y z, configure it a b c".
Please, don't hesitate to ask questions, they will be answered.