These are additional plugin modules for Bruce Guenther's mailfront SMTP daemon, updated for mailfront 2.00.

You need the mailfront software first, which you can get here:

http://untroubled.org/mailfront/

For the authres and arlog plugins, you need SPF and DKIM and DMARC libraries.

libspf2 is from http://www.libspf2.org/

libopendkim is from http://www.opendkim.org/

Both have linux packages and FreeBSD ports available. I've only built them with the FreeBSD ports.

libopendmarc is at http://sourceforge.net/projects/opendmarc/