[CentOS] configuring sendmails domain

Wed Nov 14 02:11:02 UTC 2007
Jerry Geis <geisj at pagestation.com>

I tried editing sendmail.cf and changing the Dj line to X.com
so any email originating from my machine would be X.com not m.X.com 
where m is machine name.

I typed make in the /etc/mail directory and did service sendmail restart.

This did not work. email still shows as m.X.com

What am I missing so as to NOT have the machine name in the email address.
I just want the domain.