Mazz,

Thanks for the reply - Suggestions please ?
I already run NAVP & ZA on the PC's and they are hanging off a Vigor 2200 Router.
The mail from my own mail servers (mail.oassys.com) is ok - linux 7.2 firewalled and anti-spam in place, but I am considering SPF also to rensure no relaying.
The problems I mostly get are through 'other' service providors - blueyonder & demon, they seem to let all sorts through.
I want to be able to block names/domains at their server end.

Thanks

I have a buddy that uses this: http://www.mailwasher.net/

He swears by it - apparently it works "server side"...bit too technical for me