Microsoft KB Archive/113342

= How to Test a TCP/IP Router or Multihomed Host =

Article ID: 113342

Article Last Modified on 2/20/2007

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APPLIES TO


 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows 2000 Datacenter Server
 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows NT Workstation 3.1
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Advanced Server 3.1

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This article was previously published under Q113342



SUMMARY
If you are on a subnet and are having problems talking to another subnet through TCP/IP, the following information can help you determine if the problem is with the router.



MORE INFORMATION
To troubleshoot router problems, you need a network map and the Internet addresses and subnet masks for your node, the router, the remote side of the router, and the destination node.

Example
                         Two Subnets One Router --                             |   ROUTER   | --             195.22.3.1  >   |            |   < 195.22.4.25              255.255.255.0   |            |   255.255.255.0                              |            |

|---|           |---|

|                                  |                 YOU                              DESTINATION 195.22.3.33                         195.22.4.66            255.255.255.0                        255.255.255.0

 Use the PING command to access your computer. For example:

ping 195.22.3.33

If this PING works, your node is probably okay. Use the PING command to access the 'near' side of the router. For example:

ping 195.22.3.1

If this PING works, this side of the router is okay.

NOTE: Because you can ping this address does not necessarily mean this is a router. Use the PING command to access the 'far' side of the router. For example:

ping 195.22.4.25

If this PING works, the router is working.

If it does not work, have someone use the PING command

ping 195.22.4.25

from the destination node (195.22.4.66).

If this PING works, the router is bad. Use the PING command to access the remote host. For example:

ping 195.22.4.66

If this works, TCP/IP should be working fine.