The primary troubleshooting tool for DNS included with Windows 2000 Server and other DNS implementations is Nslookup.exe. This tool can be used to perform DNS queries, obtain detailed information from the command prompt, and debug DNS problems.
You can use Nslookup in interactive and non-interactive modes. Non-interactive mode is useful for looking up a single piece of data, such as one DNS record. To use Nslookup in non-interactive mode, type nslookup <name> <server>, where <name> is the name of the record you’re looking for and <server> is the name of the DNS server you want to query.
Interactive mode is much more powerful. To enter the interactive mode, you have to type nslookup at the command prompt. You end up in the Nslookup prompt, where you can use special commands such as set or ls, which can be used to list all records or records of a given type in a specified domain. To get a list of all available commands, type ?.
The most simple use is a query for an A record. To get an IP address of a host name, just type its name in the Nslookup prompt. Nslookup will then query the DNS server for this host name and return the result. If it doesn’t return the expected result, you can debug to see the exact request and answer packets. You turn the full debugging on by typing set d2, and you turn it off by typing nod2 in the Nslookup prompt. You can also specify the type of records you’re looking for: A, CNAME, MX, NS, etc.
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