I have a Windows 2003 server DC and several other workgroup computers on the same local physical network connected to a router and then to an ISP with a dynamic address. I am trying to connect to the server via VPN and RDP. For testing I am connecting from within the same physical network using a free domain name for dynamic ISP IP address. I get the above error. I try the ISP IP address at the time and I get the same error.
Do I need to forward some port in the router in order to get to the server? If I do, what port number I need to forward and what else I need to change on the server? At present I have the specific RDP port forwarded to the server.
The client computer does not belong to the domain while the user name trying to connect does.