We have a SBS 2003 server running a VPN, and while the VPN connection is fine, network resources beyond the VPN server itself aren't always available. When clients connect, the VPN connection works just as it should. Clients have no trouble reaching the VPN server (192.168.1.145) via ping, nor do they have issues with any shares hosted on that server. However, if they attempt to access other network resources they have intermittent success.
Pinging anything beyond the VPN server on the 192.168.1.x subnet works sometimes, and sometimes it times out. When a resource can be pinged, its shares also work, and when it can't be pinged, the shares also drop. There seems to be no rhyme or reason as to when these resources work or don't work. They drop in and out repeatedly over the course of a single VPN session.
What's weird is that when a node decides to respond, the ping will time out on the first packet, then the remaining 3 will go through quickly. After that the node and all its shared resources work fine. Then I ping it again and at some point and the first ping packet responds normally and the remaining 3 time out. After that, the resource is unreachable for a while. This pattern has repeated itself multiple times. I don't know if that helps in diagnosing the problem, but I thought it was fairly odd.
The VPN is setup with RRAS using PPTP with a static pool of IPs. The remote clients all have different subnets than the VPN. As I said before, the connection itself works as it should. It's only resources beyond the VPN server that are sometimes inaccessible. Also, this inaccessibility problem is not present on clients that are actually on the local (192.168.1.x) network.
Any help would be greatly appreciated.