This is a howto on setting up a nice spam-virus fighting mailserver. It’s based on a singlebox install but spreading out the components, isn’t that difficult. I’ve tried building it so it could scale and still be easy to manage, with a lot of good webinterfaces. I think I have accomplished that - hope you can agree
Administering Dspam is a breeze. No rules to configure, new users can automatically benefit from a global dictionary and quarantine management is simple. But getting a Dspam quarantine set up the first time, without losing any email, can challenge the most seasoned mail administrators