MailScanner : Free Anti-Virus and Anti-Spam Filter ( http://www.mailscanner.info/ )
amavisd-milter : sendmail milter for amavisd-new ( http://amavisd-milter.sourceforge.net/ )
amavisd-new : High-performance interface between the MTA and content checkers ( http://www.ijs.si/software/amavisd/ )
anomy-sanitizer : Perl based e-mail filtering tool, sensitive to html tags, mime types and attachments ( http://mailtools.anomy.net/ )
anubis : GNU Anubis is an outgoing mail processor ( https://www.gnu.org/software/anubis/ )
ask : Active Spam Killer: A program to filter spam ( http://www.paganini.net/ask/index.html )
assp : Anti-Spam SMTP Proxy written in Perl ( http://assp.sourceforge.net/ )
bmf : A fast and small Bayesian spam filter ( http://bmf.sourceforge.net/ )
bogofilter : Bayesian spam filter designed with fast algorithms, and tuned for speed ( http://bogofilter.sourceforge.net/ )
clamassassin : A simple spamassassin-like script for virus scanning (through clamav) and filtering e-mail messages ( http://jameslick.com/clamassassin/ )
clamsmtp : ClamSMTP is an SMTP filter that allows you to check for viruses using the ClamAV anti-virus software ( http://memberwebs.com/nielsen/software/clamsmtp/ )
couriersrs : SRS (Sender Rewriting Scheme) wrapper for the courier MTA ( http://couriersrs.com/ )
dcc : Distributed Checksum Clearinghouse ( http://www.rhyolite.com/anti-spam/dcc/ )
disspam : A Perl script that removes spam from POP3 mailboxes based on RBLs ( http://www.topfx.com/ )
dkimproxy : An SMTP proxy server for adding DKIM headers ( http://dkimproxy.sourceforge.net )
dovecot-antispam : A dovecot antispam plugin supporting multiple backends ( http://wiki2.dovecot.org/Plugins/Antispam/ )
dovecot_deleted_to_trash : Deleted to trash IMAP plugin for Dovecot ( https://github.com/lexbrugman/dovecot_deleted_to_trash )
dspam : A statistical-algorithmic hybrid anti-spam filter ( http://dspam.sourceforge.net/ )
exim-geoip : This is an IPv4 and IPv6 capable GeoIP dlfunc library for Exim ( http://dist.epipe.com/exim/ )
exim-p0f : This is p0f version 3 dlfunc library for Exim ( http://dist.epipe.com/exim/ )
gld : A standalone anti-spam greylisting algorithm on top of Postfix ( http://www.gasmi.net/gld.html )
imapfilter : An IMAP mail filtering utility ( http://imapfilter.hellug.gr )
isbg : IMAP Spam Begone: a script that makes it easy to scan an IMAP inbox for spam using SpamAssassin ( http://redmine.ookook.fr/projects/isbg )
libdkim : DomainKeys Identified Mail library from Alt-N Inc ( http://libdkim.sourceforge.net )
libmilter : The Sendmail Filter API (Milter) ( http://www.sendmail.org/ )
libsieve : A library for parsing, sorting and filtering your mail ( http://libsieve.sourceforge.net/ )
libspf2 : libspf2 implements the Sender Policy Framework, a part of the SPF/SRS protocol pair ( http://www.libspf2.org )
libsrs2 : libsrs2 is the next generation Sender Rewriting Scheme library ( http://www.libsrs2.org/ )
libsrs_alt : Sender Rewriting Scheme library ( http://srs.mirtol.com/ )
maildrop : Mail delivery agent/filter ( http://www.courier-mta.org/maildrop/ )
mailfilter : Mailfilter is a utility to get rid of unwanted spam mails ( http://mailfilter.sourceforge.net/ )
mapson : A challenge/response-based white-list spam filter ( http://mapson.sourceforge.net/ )
milter-regex : A milter-based regular expression filter ( http://www.benzedrine.cx/milter-regex.html )
mimedefang : Antispam, antivirus and other customizable filtering for MTAs with Milter support ( http://www.mimedefang.org/ )
normalizemime : Helper program to normalize MIME encoded messages ( http://hyvatti.iki.fi/~jaakko/spam/ )
opendkim : A milter-based application to provide DKIM signing and verification ( http://opendkim.org )
opendmarc : Open source DMARC implementation ( http://www.trusteddomain.org/opendmarc/ )
opensmtpd-extras : Extra tables, filters, and various other addons for OpenSMTPD ( https://github.com/OpenSMTPD/OpenSMTPD-extras )
p3scan : This is a full-transparent proxy-server for POP3-Clients ( http://p3scan.sf.net/ )
policyd : Policy daemon for postfix and other MTAs ( http://policyd.sf.net/ )
policyd-weight : Weighted Policy daemon for Postfix ( http://www.policyd-weight.org/ )
popfile : Anti-spam bayesian filter ( http://getpopfile.org )
postfwd : Versatile Postfix policy server with a flexible ruleset based configuration ( http://www.postfwd.org/ )
postgrey : Postgrey is a Postfix policy server implementing greylisting ( http://postgrey.schweikert.ch/ )
procmail : Mail delivery agent/filter ( http://www.procmail.org/ )
procmail-lib : Procmail Module Library is a collection of modules for Procmail ( http://freshmeat.net/projects/procmail-lib )
pypolicyd-spf : Python-based policy daemon for Postfix SPF verification ( https://launchpad.net/pypolicyd-spf )
qmail-scanner : E-Mail virus scanner for qmail ( http://qmail-scanner.sourceforge.net )
razor : Vipul's Razor is a distributed, collaborative spam detection and filtering network ( http://razor.sourceforge.net/ )
rblcheck : Perform lookups in RBL-styles services ( http://rblcheck.sourceforge.net/ )
scmail : a mail filter written in Scheme ( http://0xcc.net/scmail/ )
sid-milter : A milter-based application to provide Sender-ID verification service ( http://sourceforge.net/projects/sid-milter/ )
sieve-connect : Sieve Command Line Interface ( http://people.spodhuis.org/phil.pennock/software/ )
spamass-milter : A milter for SpamAssassin ( http://savannah.nongnu.org/projects/spamass-milt/ )
spamassassin : An extensible mail filter which can identify and tag spam ( http://spamassassin.apache.org/ )
spamassassin-botnet : SpamAssassin plugin that attempts to detect messages sent by a botnet ( https://wiki.gentoo.org/wiki/No_homepage )
spambayes : An anti-spam filter using on Bayesian filtering ( http://spambayes.sourceforge.net )
spamdyke : A drop-in connection-time spam filter for qmail ( http://www.spamdyke.org/ )
spampd : spampd is a program to scan messages for possible Unsolicited Commercial E-mail content ( http://www.worlddesign.com/index.cfm/rd/mta/spampd.htm )
spamprobe : Fast, intelligent, automatic spam detector using Bayesian analysis ( http://spamprobe.sourceforge.net/ )
sqlgrey : SQLgrey is a postfix policy service implementing a grey-listing policy ( http://sqlgrey.sourceforge.net/ )
tmda : Python-based SPAM reduction system ( http://www.tmda.net/ )
zdkimfilter : DKIM filter for Courier-MTA ( http://www.tana.it/sw/zdkimfilter )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a gentoo
For Paludis use this rsync : rsync://gentoo.zugaina.org/gentoo-portage
If you have a problem : ycarus(-at-)zugaina.org