[Mimedefang] Adding support for learning our addresses

[Damrose, Mark]

> -----Original Message-----
> From: Philip Prindeville

> On the other hand, if, like me, your local address *is* 
> unroutable, then it means that you're behind a firewall, and 
> need to do a gethostbyname() on your own name to figure out 
> what your outside address is (i.e. what the address of your 
> firewall is that proxies for you).

That wouldn't work on my system, and many others.  If you do a
gethostbyname() you'll get the local unroutable address back - 
since the internal and external DNS for my namespace are maintained
on separate servers.

If you are using NAT, then in order to accept mail to 
postmaster@[ip.add.re.ss] (see RFC1123 Section 5.2.17), you'll need 
to include [ip.add.re.ss] in /etc/mail/local-host-names.  Why not 
read that file?