GMS needs to know which domain it is managing in order to make sure that email is posted out correctly. This will help to prevent mail loops (where lots of CPU is used and no messages are delivered) and help to stop mail being delivered incorrectly.
GMS must perform a reverse lookup on itself before posting. To perform a reverse lookup it retrieves the machines TCP/IP identity by building the machine name from the host name and domain name.
The default installation of RedHat asks you to enter the fully qualified machine name as the host name.
Host Name: mail.domain.dom
Domain Name: (none)
This will build a machine name of mail.domain.dom.(none), which will cause the reverse lookup to fail. To correct this you must change the host name and domain name to be:
Host Name: mail
Domain Name: domain.dom
You can change these by using the “hostname” and “domainname” commands in RedHat, e.g.
hostname mail domainname domain.dom
or by editing the /etc/hosts file directly.
Keywords:RedHat, TCP/IP, Domain Name, Host Name, Domain, POST,outgoing, queue