Windows 8 In Depth

Advanced Routing for Remote Networks

As discussed previously, if you use dial-up or Virtual Private Networking to connect to a remote network with more than one subnet, you usually must let Windows set the default gateway to be the remote network. Otherwise, Windows won’t know which network hosts must be reached through the VPN or dial-up connection and which should be reached through your Internet connection. Unfortunately, all your Internet traffic will travel through the tunnel, too, thus slowing you down. The remote network might not even permit outgoing Internet access.

The alternative is to disable the use of the default gateway and then manually add routes to all subnets known to belong to the private network.

To disable the default gateway, ...