Solve Windows 2000 DNS server problems Peter Parsons MCSE, TechRepublic.com DNS is the backbone of Windows 2000 Active Directory. If it fails, so does your network, so it's important to know how to troubleshoot a faulty DNS server. If there's one component of Windows 2000 that needs to be solid from the get-go, it's DNS. DNS is the backbone of Windows 2000 Active Directory, the repository of the information your network's hardware and software need to communicate. If DNS fails, so does your network. To keep that from happening, I'll show you what's involved in troubleshooting a faulty DNS server. Start with the basics
If you're having DNS problems, you don't want to get out your Windows CD-ROM and start reinstalling software. There are many things you can do to diagnose and solve DNS problems before taking drastic steps. The best way to fix these problems is to start with the basics. If a user reported the DNS trouble, the first thing you should do is try DNS out yourself. Even though you can do that simply by opening a browser window, you can also PING the user's workstation using the workstation's DNS name rather than an IP address. If you get a response, you know DNS is working because PING uses DNS for name resolution. If PING doesn't return a response, you first need to check all the obvious weak links before you start fiddling with the DNS installation. These weak links include the network card, cables, and any router that the user may be sending packets through. At the user's workstation, you should run IPCONFIG /ALL from a command line to see whether the TCP/IP stack on the local machine is responding correctly. If you're running DHCP, try running IPCONFIG /RELEASE followed by IPCONFIG /RENEW. Running these two commands back to back will renew the IP address lease and refresh the workstation's DHCP options. If you run IPCONFIG /FLUSHDNS, you can flush the local host's resolver cache. After that, run IPCONFIG /REGISTERDNS to check the event log and zone file for errors and updates, respectively. If you're lucky, this could be all you need to do to isolate and fix the problem. If you need more help diagnosing DNS, you can use an NSLOOKUP query. NSLOOKUP is a command line utility that allows you to query DNS server zone files. Just as with any other service, the Event Viewer is a gold mine of information when resolving DNS errors. Some of the common DNS errors you may find in Event Viewer include:

• 132 (Warning) DNS_EVENT_NBSTAT_ADAPTER_FAILED
• 404 (Error) DNS_EVENT_CANNOT_BIND_TCP_SOCKET
• 409 (Warning) DNS_EVENT_UPDATE_LISTEN_ADDRESSES
• 500 (Error) DNS_EVENT_INVALID_REGISTRY_ZONE
• 1003 (Error) DNS_EVENT_CACHE_FILE_NOT_FOUND


For a complete list of DNS Errors found in Event Viewer, visit Microsoft's TechNet Knowledge Base.