These ebuilds come from http://overlays.gentoo.org.
If you have some problems, go to the official site first.
dkimproxy : An SMTP proxy that signs and/or verifies emails using the Mail::DKIM module ( http://dkimproxy.sourceforge.net/ )
dovecot-antispam : A dovecot antispam plugin supporting multiple backends ( http://johannes.sipsolutions.net/Projects/dovecot-antispam )
sbd-proxy : An SMTP proxy for solicited bounce detection ( http://dev.gentoo.org/~wschlich/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a wschlich-testing
For Paludis use this rsync : rsync://gentoo.zugaina.org/wschlich-testing-portage
If you have a problem : ycarus(-at-)zugaina.org