[michaelsanford]

I noticed the same behaviour, which seemed to be caused by my DHCP controller (i.e., my router).

I have an iBook with two interfaces (iBookEN and iBookAP for ethernet and airport respectively). I use two pipes for a complex QoS implementation.

I noticed that, even though my hostname in System Preferences was iBook, it would take on the hostname given by my DHCP controller (or, more specifically, the one provided as a DHCP Client ID, given above).

But, after having used two routers (a Linksys WRT54G-CA v6 with dd-wrt custom firmware and a DLink DI-624 with 2.76) I have only experienced hostname changes with the Linksys, not with the DLink.