Product Reviews

A Few of My Favorite Things: DCDiag

Compaq knows a thing or two about troubleshooting large networks. Here are some of the utilities and programs it uses most and likes best for Windows 2000.

• By Fred Grant
• 08/01/2001

In the Support Tools directory on the Win2K CD, DCDiag provides a number of tests that can help determine the health of individual DCs, all DCs in a site, or all DCs in an enterprise.

When no tests are explicitly specified, DCDiag tests connectivity, replication, topology integrity, Check NC Head Security Descriptors, Check Net Logon Rights, Locator Get Domain Controller, Intersite Health, Check Roles and Trust Verification. For each of these tests, DCDiag shows the success or failure of the test with more detail provided with the /v switch.

Although DCDiag features a number of diagnostic tests, I use it most frequently to quickly diagnose replication problems like the one shown in the figure. It provides a quick way to determine which DC replication partners are unreachable and how long it’s been since replication last occurred. Other tools also do this, but I find DCDiag the easiest to use for a quick overview that doesn’t require the use of lengthy GUIDs.

DCDiag can help you determine if a server has replication problems. (Click image to view larger version.)

The following shows part of the output obtained from running DCDiag on a DC (RISRV01) when one of the other DCs (MASRVONE) isn’t available on the network.

[Replications Check,RISRV01] A recent replication attempt failed:
   From MASRVONE to RISRV01
   Naming Context: CN=Schema,CN=Configuration,DC=cpqri,DC=com
   The replication generated an error (1722):
   The RPC server is unavailable.
   The failure occurred at 2001-05-06 16:52.46.
   The last success occurred at 2001-05-05 20:51.49.
   20 failures have occurred since the last success.
   [MASRVONE] DsBind() failed with error 1722,
   The RPC server is unavailable..
   The source remains down. Please check the machine.

Although useful for detecting errors on DCs, manual intervention is still required to fix the errors that are detected.