NetDiag provides a master class in testing Network Availability. When you run NetDiag from the command line it carries out a battery of tests, which test your servers' ability to operate successfully. As usual, my goal in this NetDiag tutorial is to show you how to get testing your Lan or Wan network.
Even if there is no problem with your Active Directory, it is still worth running NetDiag to learn about a healthy operating system, for example, NetDiag checks the NIC bindings. Get a free copy of Netdiag at the end of this page.
Examples of NetDiag
- Installing Exchange and you wish to check that you can connect to other servers.
- Checking VPN network tunnels on the WAN.
- DNS problems. Computers cannot 'see' their domain controller on the LAN.
- A quick check on hotfixes.
- Check the Network Card Bindings from the command prompt.
- You are having problems with IPSEC.
- Winsock corruption, wrong version incompatibilities.
- NetDiag checks that Domain Controllers are all able to 'speak' LDAP.
Installing NetDiag
NetDiag magically appears after you install the Support Tools from the Windows Server 2003 CD. Once NetDiag.exe (and Support Tools) is the path then you can run it from any command prompt.
NetDiag switches
/v If you need the full report on your network availability, then append this verbose switch to the command. Unlike the /v of other utilities, NetDiag /v really does produce chapter and verse on your network cards and their binding.
/Debug This debug switch was disappointing in that it did not produce any more details than those supplied by the /v. Perhaps I would have received extra information if my Windows Server 2003 really had a network connectivity problem.
/q When you just need to know if there are any errors, this is the switch for troubleshooting. The /q is the antithesis of the /v and /debug.
/test: Unlike DCDiag, NetDiag's test switched worked perfectly. What is more the command:
netdiag /test produced the following list of possible tests:
- NetSh PowerShell