Just wanted to let you all know that Gandi.net the cheapest and best
domain register has switched recently to a non 2045
compliant mailer to send confirmations. So after 7 months of happily
using courier I will be switching to something
more open to stupidity.
Stick a qmail or sendmail box to listen on your inbound port 25, then
forward all mail to the courier box. You can do your authentication
checking with the q/s box and/or MAPS for spam. Anything that comes
through the q/s box will be considered a degree more trustable.