confusing hostname question


My powerbook is called SilverBullet, defined in the sharing Pref.Pane.
When I open a new terminal window, it normally shows SilverBullet:~kon$

But for some reason when I attach my powerbook to my friends Active Directory network (DHCP, DNS, etc) and open terminal, all of the sudden my terminal show w0121p:~kon$
Which happens to be a name of a Windows machine on his network that has been off for some time.

Why does this happen? I'm sure it has something to do with DNS or for that matter DDNS. But when we looked up in his DNS table, it had my IP with the name SilverBullet next to it just like it should.

For the life of me I can't figure out where this w0121p would come from.