How To Configure Windows NT as a Remote IP Router

 Last reviewed: December 31, 1997
Article ID: Q123024

The information in this article applies to:
  • Microsoft Windows NT Workstation version 3.5
  • Microsoft Windows NT Server version 3.5
  • Microsoft Windows NT Server version 4.0
  • Microsoft Windows NT Workstation version 4.0

SUMMARY

This article describes how to configure Windows NT Workstation or Windows NT Server to serve as an IP router from a subnet to an Internet/enterprise gateway using dual network interface cards (NICs). (When Windows NT has more than one NIC installed it is referred to as a multi-homed system.)

HOW TO CONFIGURE WINDOWS NT AS AN IP ROUTER

Install and bind TCP/IP to both NICs. Assign the correct IP address to each NIC respective to the subnet in which it resides. Check that IP routing has been enabled by using the IPCONFIG /ALL command.

EXAMPLE CONFIGURATION

In the following example you should configure the 199.55.10.1 NIC to a default gateway of 199.55.10.252. The 212.56.11.1 NIC should be configured with a blank default gateway: 

   Multi-homed Windows NT 3.5 TCP/IP Workstation/Server
   ----------------------------------------------------
           |                             |
           |                             |
           |                             |
          NIC                           NIC
      212.56.11.1                   199.55.10.1
      -----------                   -----------
           |                             |
           |                             |
           |                             |
      Network ID:                   Router to Internet/
      212.56.11.0                   enterprise default
                                    gateway port address:
                                    199.55.10.252
The IPCONFIG /ALL command should display something similar to the following:

Windows NT IP Configuration 

        Host Name . . . . . . . . . : gha-1
        DNS Servers . . . . . . . . :
        Node Type . . . . . . . . . : Hybrid
        NetBIOS Scope ID. . . . . . :
        IP Routing Enabled. . . . . : Yes
        WINS Proxy Enabled. . . . . : No
        NetBIOS Resolution Uses DNS : No
Ethernet adapter Lance1: 

        Description . . . . . . . . : DEC Etherworks Turbo Adapter
        Physical Address. . . . . . : 08-00-2B-30-D1-E0
        DHCP Enabled. . . . . . . . : No
        IP Address. . . . . . . . . : 199.55.10.1
        Subnet Mask . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . : 199.55.10.252
Ethernet adapter EE162: 

        Description . . . . . . . . : Intel EtherExpress 16 Miniport
        Physical Address. . . . . . : 00-AA-00-44-B4-CB
        DHCP Enabled. . . . . . . . : No
        IP Address. . . . . . . . . : 212.56.11.1
        Subnet Mask . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . :
The ROUTE command is provided as an interface to manipulate the routing table. You can use ROUTE PRINT, ROUTE ADD, ROUTE DELETE, and ROUTE CHANGE to modify the routing table.

The ROUTE PRINT Command should show only one default gateway: 

   Network Address   Netmask   Gateway Address   Interface     Metric
   0.0.0.0           0.0.0.0   199.55.10.252     199.55.10.1   1
A static route also needs to be added to the router at 199.55.10.252 providing a route back to the 212.56.11.0 network. Add the 199.55.10.1 gateway address as the static route to the 212.56.11.0 network. The method of adding this static route will vary among routers.

NOTE: Each NIC must be on a different subnet in order to route between the segments. If they are on the same subnet, the procedure above does not work as it is requesting the Windows NT computer to act as a bridge. Microsoft Windows NT does not function as a bridge and is not supported acting as a bridge.

Additional query words: prodnt multihomed
Keywords : nthowto ntnetserv NTSrvWkst nttcp kbnetwork
Version : 3.5 4.0
Platform : winnt

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Last reviewed: December 31, 1997
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