Configuring multiple gateways on a network in Windows 7

If you have multiple network adapters in your computer and you configure a default gateway for each adapter (which creates a default route in the IP routing table for all destinations that are not located on the subnet), information on your network might not be routed to the correct destinations if you connect to disjoint networks—separate networks that are not designed to communicate directly.

Only a single gateway is used for all destinations that are not located on the subnet, even when you configure multiple default gateways. An example of this is when a computer is connected to both an intranet with multiple subnets and the Internet. With a default gateway configured for both adapters, you can either communicate with all computers on the Internet or all computers on the intranet, but not both.

To solve this problem, do the following:

1. Configure a default gateway for the network adapter that's connected to the network with the most routes (usually the network adapter that's connected to the Internet).
2. Don't configure a default gateway for any other network adapter. Instead, use static routes or dynamic routing protocols to add the routes for the other disjoint networks to the local IP routing table. If the routing infrastructure uses Routing Information Protocol (RIP) for IPv4, you can turn on RIP Listener in Windows, which allows your computer to learn other routes on the network by "listening" to broadcast RIP messages, and then adding IPv4 routes to the routing table. If the routing infrastructure doesn't use RIP, you can't use RIP listening.

To configure a default gateway

1. Go to Control Panel and then open Network and Sharing Center, then click on Change adapter Settings option in the left pane.
2. Right-click the network adapter that you want to configure a default gateway for, and then click Properties. If you are prompted for an administrator password or confirmation, type the password or provide confirmation(depend on UAC level).
3. Click the Networking tab.
4. Under This connection uses the following items, click either Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol Version 6 (TCP/IPv6), and then click Properties.

5. In the dialog box that appears, select either Obtain an IP address automatically or Use the following IP address.

If you configure the network adapter to obtain an IP address automatically, the default gateway is assigned by the DHCP server. If you specify an alternate configuration (IPv4 only), the default gateway is the IP address in the Default gateway box on the Alternate Configuration tab. You can only specify one default gateway.

If you manually specify an IP address configuration, the default gateway is the IP address in the Default gateway box on the General tab.

To turn on RIP Listener

1. Go to Control Panel, then open Programs and Features.
2. In the left pane, click Turn Windows features on or off. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
3. Select the RIP Listener check box, and then click OK.

You can also manually configure the IPv4 & IPv6 settings.