Dcdiag - checking DNS

Dcdiag.exe is a command-line tool that most administrators know about. It's great for troubleshooting various domain and domain controller (DC) issues, and in Service Pack 1 for Win2003, it has picked up some new capabilities.

Run Dcdiag /TEST:DNS to test the health of AD's DNS infrastructure. By default, this tests both basic DNS functionality, forwarders or root hints, delegation, dynamic updates, record registration, external name resolution, and Internet host resolution (it checks for http://www.microsoft.com/ by default). This is a great one-command test to see how your entire DNS infrastructure is working.

A second is Dcdiag /TEST:CheckSecurityError, which looks for basic security problems.
As always, you can run Dcdiag right on a domain controller or from your client workstation (although you'll need to specify a server or naming context so that Dcdiag knows what to test; use the /s: argument to specify a DC server name).

Tool Location
The Dcdiag command-line tool is included when you install Windows Server 2003 Support Tools from the product CD. For more information about how to install Windows Support Tools, see Install Windows Support Tools (http://go.microsoft.com/fwlink/?LinkId=62270

To install Windows Support Tools

1. Insert the Windows CD into your CD-ROM drive.
2. Click No if you are prompted to reinstall Windows.
3. When the Welcome screen appears, click Perform additional tasks, and then click Browse this CD.
4. Go to the \Support\Tools folder.
   For complete setup information, refer to the Readme.htm file available in this folder.
5. Double-click suptools.msi.
6. Follow the instructions that appear on your screen.