Troubleshooting Gateways

If you see the message "Your default gateway does not belong to one of the configured interfaces.." during setup, find out whether the default gateway is located on the same logical network as the computer's network adapter. The easiest way to do this is to compare the network ID portion of the default gateway's IP address with the network IDs of the computer's network adapters. In other words, check that the bitwise logical AND of the IP address and the subnet mask equals the bitwise logical AND of the default gateway and the subnet mask.

For example, a computer with a single network adapter configured with an IP address of 172.16.27.139 and a subnet mask of 255.255.0.0 requires a default gateway of the form 172.16.y.z. The network ID of the IP interface is 172.16.0.0/16. Using the subnet mask, TCP/IP can determine that all traffic on this network is local; everything else must be sent to the gateway.

© 1985-2000 Microsoft Corporation. All rights reserved.