setting hostname for COX w/DHCP

[jasonp]

Here's my situation:
Previously on @home I had a static IP address and an assigned hostname and 
all was well.
With the new Cox conversion for the most part the network is working with 
DHCP. I'm using "pump" as a DHCP client on RedHat 7.1

The one problem I'm having is that I don't have a valid hostname anymore.
This was causing me a problem sending mail.
I was using Kmail as a reader and sendmail as a MTA, but that didn't work.
It came up with errors: "cannot route to host" using the old @home hostname, 
or "does not exist" when I made up one randomly.
As a workaround I use the Cox SMTP server and that works, but I'd like to 
have a valid hostname for sendmail.

So, has anyone else gotten the hostname set correctly with a similar setup?
Is it possible anymore?

Jason Phillips