dcc : Distributed Checksum Clearinghouse ( http://www.rhyolite.com/anti-spam/dcc/ )
postgrey : Postgrey is a Postfix policy server implementing greylisting ( http://postgrey.schweikert.ch/ )
razor : Vipul's Razor is a distributed, collaborative spam detection and filtering network ( http://razor.sourceforge.net/ )
spamassassin : SpamAssassin is an extensible email filter which is used to identify spam ( http://spamassassin.apache.org/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a argent-main
For Paludis use this rsync : rsync://gentoo.zugaina.org/argent-main-portage
If you have a problem : ycarus(-at-)zugaina.org