Hello. I have sendmail 8.13.6 on Fedora 4 and seem to have a problem
with other sites being able to identify mail from my server and in
consequence blacklisting me.

Basically, my sendmail server still sends the machine name even though
sendmail.mc has been compiled with these settings:
MASQUERADE_DOMAIN(localhost)dnl
MASQUERADE_DOMAIN(localhost.localdomain)dnl
MASQUERADE_DOMAIN(hostname)dnl
MASQUERADE_AS(mydomain.com)dnl

and the top line of /etc/hosts is
127.0.0.1 hostname localhost.localdomain localhost

Yet I still get a few bounces because other sites say my machine is
sending as user@hostname instead of user@mydomain.com. Additionally,
some complain that HELO is localhost.localdomain.

Any advice on how to clean this up?