It got really annoying for me to see how my terminal prompt kept changing when I connected my Macbook from work. I know I can easily fix this by setting my prompt in my .profile file, but I wanted to find out why this was happening.

It turns out the culprit is DHCP. By Default the hostname is determined dynamically on your macbook. This setting can be controlled with your /etc/hostconfig file. Here is what it looks like on my laptop -

\# This file is going away

AFPSERVER=-NO-  
AUTHSERVER=-NO-  
TIMESYNC=-NO-  
QTSSERVER=-NO-

To hard code a hostname, I just added “HOSTNAME=MyMacBook” (without the quotes) to the end of the file.
Some might consider the changing hostname a feature they might want. Not me ;)