To confirm that the server's hostname is configured properly on the host and in DNS do the following from a terminal:
% hostname
This should output the Fully Qualified Domain Name (FQDN) like this

your_server.domain.edu

Now do a forward lookup:
% host your_server.domain.edu
You should get a response like the following

your_server.domain.edu has address 192.168.0.1

Make sure the IP is correct for your network. Now do a reverse lookup:
% host 192.168.0.1
You should get a response like the following

1.0.168.192.in-addr.arpa domain name pointer your_server.domain.edu

Now verify that the dynamically generated localhost name is correct (if forward and reverse DNS were setup properly it will be):
% sudo changeip -checkhostname
Make sure the current hostname and DNS hostname values match

You can also use dig to perform a quick forward and reverse DNS check:
dig your_server.domain.edu
...and to check reverse
dig -x 192.168.0.1


Updated --- brianmacpherson brianmacpherson Feb 7, 2009