I have asked a similar question to this before and thought the problem was resolved but it seems to be still here. This problem is doing my head in now!
I have a routing and remote access server setup for remote access, thats its only use, nothing else. I have one of its interfaces setup for the internal network, and the other setup the same but with a different IP. I then have a cisco router which port forwards the VPN port to 192.168.26.161 (the 2nd interface of the routing and remote access server). This interface is setup with default gateway dns etc.
In routing and remote access I have 192.168.26.161 as the interface connected to the internet, and have created an access rule for a group in active directory to access this, and this authenticates users correctly.
On each machine I setup the VPN on, I have it setup so they use the remote networks default gateway. On the server I also have it setup to use DHCP relay to my DHCP server/DNS Domain controller server (192.168.26.5).
Now when I connect it authenticates me fine and the other users I setup.
Now strangely I cannot ping 192.168.26.5, but i can ping all other internal addresses. I cannot ping by name, obviously because i cannot communicate with DNS server (192.168.26.5).
Sometimes it seems to work, and others it doesnt... and its really starting to make me tear my hair out now!
Additionally and I am not sure this has anything to do with anything, i get a dfgw or 0.0.0.0 on my laptop when i do IPCONFIG /ALL... everything else looks correct so DHCP is working ok.
Everything on my internal network works fine, and there are no glaringly obvious messages in the event logs of either my routing and remote access server, or the domain controller...
Any help with this is VERY appreciated!