I have a client that is having some issues with DNS resolution over the SSL and remote user VPN. When they have a remote user logged in over the SSL VPN or the remote user VPN it takes over a minute to resolve a name while mapping a drive. I have checked and the internal DNS servers are listed, but it appears that the external DNS servers are taking precedence over the internal DNS servers. We are using a Cisco 3000 VPN concentrator for the SSL VPN and remote user VPN.
I have this problem too.