How do fqdnaliases work ?

[Jan Rychter <jwr@icm.edu.pl>]

I'm using 2.99.46. How do I use the fqdnaliases ?

Say, I want to create an alias:

someuser@thisdomain.com: otheruser@otherdomain.com

Do I add thisdomain.com to localnames ? Simply adding the alias as above
to fqdnaliases and running newfqdnaliases doesn't seem to do anything on
my machine. Or do I need to flag something at compile-time, too?

thanks,
--J.