dcc : Distributed Checksum Clearinghouse ( https://www.rhyolite.com/dcc/ )
openarc : Open source ARC implementation ( https://github.com/trusteddomainproject/OpenARC )
opendkim : A milter providing DKIM signing and verification ( http://opendkim.org/ )
opendmarc : Open source DMARC implementation ( http://www.trusteddomain.org/opendmarc/ )
postgrey : Postgrey is a Postfix policy server implementing greylisting ( https://postgrey.schweikert.ch/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a oubliette
For Paludis use this rsync : rsync://gentoo.zugaina.org/oubliette-portage
If you have a problem : ycarus(-at-)zugaina.org