Something else to remember.
Not only do the clients need to know where the GUP is, but the potential GUP itself must know so too.
Do you have different LiveUpdate policies applied to your servers and workstations?
- If yes. make sure that both LiveUpdate policies have got your server defined as a GUP.
- If no, review the links posted by Brian81 above, review the SYLINK log files and test (using HTTP or telnet) if TCP port 2967 is active
Those machines are not updating when in the office
Your GUP is on the same remote site?
(the laptops appear to pull down updates from Live Update when they are not in the office)
In your LiveUpdate policy, do you have the option set to use the default Symantec LiveUpdate server? See this screen shot: