Windows 7 workstations that are joined to a Windows Server 2003 R2 domain are unable to access file shares after being moved to a remote location via a VPN. The workstations were previously on the corporate (HQ) network and could access shares just fine. What has changed is their physical location, IP address, and the introduction of a VPN.
I believe this is an issue with this Server 2003 box (that is also the domain controller) that is somehow rejecting or otherwise blocking authentication requests to the remote site.
The HQ network IP range is 10.100.1.x, subnet 255.255.255.0 The remote site IP range is 10.100.2.x, subnet 255.255.255.0
VPN is gateway-to-gateway between two Netgear UTM9S appliances.
Everyone can ping one another from either side. RDP also works from either side. And you can browse available file shares on the domain controller, even access SYSVOL or NETLOGON shares without issue. So I do not believe this is an issue with the VPN itself, because the only failure is share access that requires authentication.