5.4 Sendmail only listening on localhost?

[Chris Moran]

OK, I have to be doing something silly here...
 
I have installed a clean system with 5.4-RELEASE (on a 1.2GHz Athlon, 512MB RAM, lots of disk, etc).
 
Machine has to NICs, one for the "public" and one for the "private" networks here.  However, Sendmail is only listening on port 25 on localhost.
 
I don't confess to being knowledgeable about sendmail configuration, and I figure it's in the mc file someplace, but where do I tell sendmail to listen on one (or more) of the NICs?
 
So far clean installs on 3 machines show the same thing, so I guess this is the default, secure config?
 
Thanks