Default Gateway Configuration for Multihomed Computers
A multihomed computer is one that has multiple network interfaces. For computers using TCP/IP, these interfaces can be separate network interface cards (NICs) or multiple IP addresses on one NIC. This article discusses the recommended method of configuring the default gateway on multihomed computers.
In the TCP/IP properties of each of the products listed above, you have the
option to configure a default gateway for each NIC or multiple default
gateways for the same NIC. Every NIC that has a default gateway adds a
0.0.0.0 route (default route) to the routing table.
In either case, the TCP/IP routing table will have multiple default routes listed (to view the routing table, type "ROUTE PRINT" from the command prompt). The route most likely to be used is the default gateway for the primary NIC that is bound to TCP/IP, but this is not always the case. If the Transmission Control Protocol (TCP) session on the active default gateway times out, TCP can switch to the next default gateway. This can present a problem depending on your network configuration.
It is not recommended to have multiple adapters configured on the same network (it may even create more overhead). For more information on TCP/IP behavior when multiple adapters are configured on the same network, please see the following article in the Microsoft Knowledge Base:
Q175767 Expected Behavior of Multiple Adapters on Same NetworkIf both NICs are on the same contiguous network, this should not be a problem as long as the default gateways are valid. However, if the NICs are configured on disjoint networks, or networks that are physically separated and cannot communicate with each other, you will not be able to communicate with the destination host reliably.
Q128978 Dead Gateway Detection in TCP/IP for Windows NT
Q171564 TCP/IP Dead Gateway Detection Algorithm Updated for Windows NTOnly one default gateway should be configured on any multihomed computer. The default gateway is a global configuration for the server, not a setting that must be set for each network adapter. The server is already aware of all the networks it is directly connected to, and adds a route to each network for which it has a TCP/IP address.
Q169161 Registry Parameters for RIP for IP Version 1
Additional query words: multi-homed multi homed
Keywords : kbnetwork win95
Issue type : kbinfo
Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351xsearch kbWinNT350xsearch kbWinNT400xsearch kbWinNTW350 kbWinNTW350xsearch kbWinNTW351xsearch kbWinNTW351 kbwin2000AdvServ kbwin2000AdvServSearch kbwin2000S kbWinNTW310 kbWinNTSsearch kbWinNTS400xsearch kbWinNTS400 kbWinNTS351 kbWinNTS350 kbWinNTS310 kbWinNTAdvSerSearch kbWinNTAdvServ310 kbwin2000Ssearch kbwin2000Search kbwin2000ProSearch kbwin2000Pro kbWinNTS351xsearch kbWinNTS350xsearch kbWinNTS310xsearch kbWinNT310xSearch kbWinNTW310Search
Last Reviewed: March 9, 2001