How to Configure RRAS DOD to Interoperate with Third-Party Unnumbered Connections (226322)

SUMMARY

When Dial on Demand (DoD) in Routing and Remote Access Service (RRAS) is used to connect to a terminal server, the terminal server may give out an IP address on the same subnet as the LAN that the RRAS server is connected to. As a result, the clients on the local LAN and the remote side of RRAS server fall within the same IP network.

A number of hardware routers/terminal servers allow you to do this with "Unnumbered connections". RRAS can be configured to work with these kinds of routers, so that you do not have to subnet the range of IPs that you have been given from an Internet Service Provider (ISP).

MORE INFORMATION

In RRAS, when dialing a third-party terminal server or router that supports unnumbered connections, configure the following:

Use an arbitrary static pool. An example of an arbitrary static pool to use would be 10.0.0.248/29.
Create the DoD connection. Configure the DoD connection to dial into a "non-Windows NT router" that expects you to know your IP address.
Add a static route. When connecting your LAN clients to the Internet, the typical entry would be a default gateway route. This default gateway route is associated with the DoD connection to the ISP. This can also be a specific route for remote networks.
On the DoD connection, prerequest the IP the router wants to give you. Do not use "server assigned" address. In order for unnumbered connections to work, it is important to know the IP address that will be assigned by the router/terminal server
Change the IP on the LAN network card so that it is not the same as the IP you are requesting from the DoD (this is important - routers that support unnumbered connections seem to want these to be the same, but RRAS does not. So make sure the IP bound to the network adapter is not the same as the one you are prerequesting, although it does have to be the same Network ID). For example, if the IP assigned by the dial-up device was always going to be 131.107.0.1, then the IP assigned to the network adapter could be 131.107.0.2. This would work well.