The VPN connection connects quickly and works for a while. It will quietly fail after a random amount of time. Disconnecting and connecting makes it work again for a while. When it is not working, I cannot ping address on the internal network (therefore this is not a DNS issue). Both ends (RRAS and the client) show that the connection is connected. The client has no problem getting to internet sites (I have unchecked the "use default gateway on remote network") while the VPN is dead. The VPN does not recognize it is dead and therefore does not auto redial (it will redial properly if I unplug/plug the cord). Other computers in the same office (therefore using the same internet connection) work properly before, during, and after the other computer goes dead. On some days it might be hours before the connection fails, and other days it might fail almost immediately after connecting.
I have 2 different setups that exhibit the same behavior. Neither setup is related to the other. Both are Win 2k8 R2 servers running RRAS to provide the VPN server. One is the DC (so this is a multi homed DC), the other is not. I did not change VPN settings from the defaults.
A win 7 client has had this problem, and so has a win XP client. We use the built in windows VPN. The bad behavior has happened from 2 different locations.