Auth SMTP Mysql Freebsd

Hi All

I need to set up an auth smtp mailserver. Exim seems to be the sensible
choice and MySQL would be a handy place to keep the user/pwords.

I have found myriad articles all doing it in a different way and none of the
actually work straight off the page for FreeBSD. Help. Do I need SASLauthd
for example or can I just use Exim and Mysql?

Thanks for your time, if I get this resolved I will type up a short how to.