Problem with RRAS VPN - 2003

Hello,

I have a Windows 2003 box that has been running as an RRAS VPN server
for the last year, and I have never experienced any problems. As of
yesterday, users can sucessfully connect to the VPN, but they only have
intermittent access to the resources beyond the VPN. For example, they
may be able to get to IP1, but not IP2 (on the same subnet). The next
time they connect to the VPN, they may be able to get to IP2, but not
IP1.

These same users can access the entire network if they sit down in the
office; it's the VPN that's problematic. I've disabled and recofigured
RRAS on the problematic machine, to no avail.

For the time being, I've moved RRAS to a different machine, and it
seems to be working; however, I'm concerned that this will happen
again, and I would like to find a solution.

Can anyone explain this behavior?

TIA

Chris