Here's the weird thing....the correct name is in the /etc/hosts file.
The name of the server is server.dallas.com. (Not really but you get the point). One of our techs wants to name it Server_Dallas so when he logs on via ssh he can keep track of it and not get confused with any other machines he logs into. So he does sysctl kernel.hostname=Server_Dallas. After he does that Sendmail refuses to send any email to us when I try:
. I can post the log files if it will help. When I open /etc/hosts I see the correct IP with server.dallas.com in there AND Dallas_PBX.
When I use the command "hostname" I see "Server_Dallas". I then use sysctl kernel.hostname=server.dallas.com. I type hostname again and see "server.dallas.com". Now when I email it works. What the!?