There are two things that might be the issue:

1st) You laptop has a fixed network address for your work network, and/or home network doesn't provide a dynamic network address.

2nd) You're work network is probably behind a firewall and proxy server, and for browsing the internet you need to set up the proper proxy address on the browser.

On FireFox the SwitchProxy add-on is usefull for changing proxy on the fly with just a right-click of the mouse...

SyncMaster: both of the previous posts where spam, so I deleted them.