There’s a problem when connected to a VPN using Windows XP.
If a hostname whatever.domain.com resolves internally to an IP that differs from what the same hostname resolves to externally then you’re going to hit this issue.
The first thing you would generally do is make sure that the Remote Access connection is at the top of the binding order in advanced network settings.
However, this doesn’t work!!! This is a known bug to Microsoft and has NEVER been fixed!
You basically need to make the same change, but do it via the registry.
Change the key called ‘Bind’… ensure that the value “\Device\NdisWanIp” is at the top of the list.