submit.cf

[stupidmail4me]

What exaclty is this file for? I know that
localhost.cf is the default an doesn't accept
connections from the outside world. sendmail.cf is for
accepting connections to the outside world. But I
can't find anything about submit.cf that explains
exactly what it does.
Everyone is raving about the all-new Yahoo! Mail beta.
http://new.mail.yahoo.com