wrong name on emails

[M.D. DeWar]

Hello,
When I first setup from FreeBSD 4.8 box I gave it one name, badboy. Then
later to due to dns issues I changed it to match DNS. Now when I get an
email from the box it says root at badboy.domain.com instead of the new name.
I searched every file I can think of. rc.local,rc.conf , resolv.conf and
other files but with no luck.
I tried egrep -iR "badboy" /
to find it but it was taking a long long time. So killed it.
Were do I find it and change it or is it permanently at the original
hostname.

Thanks
Mark