Resolving problems with DNS, Active Directory, and Group Policy

Escaping the Trap

Incorrect name resolution and network connectivity are the most common problems on networks. Therefore, if a service on one or more computers fails or if connectivity and performance problems occur, always check first whether name resolution and the connection between the servers and clients is working optimally. At the command prompt, nslookup checks to see whether the name of the server can still be resolved on the computers involved, which can often help delimit errors. All participating servers – and clients – need to be able to resolve one anothers' addresses.

Name Resolution and Network Connectivity

Name resolution plays an important role: The nslookup command must return the server IP address correctly. However, this does not work in nested structures until you have configured Domain Name System (DNS) servers for the subdomain on the subdomain controller and the DNS server has registered. To use other DNS servers for name resolution on the local machine, run nslookup <host> <server> at the command line as follows:

nslookup dc02.microsoft.com dc01.contoso.com

Here, nslookup attempts to resolve host dc02.microsoft.com using server dc01.contoso.com . Instead of the second entry, you could specify the IP address.

If you enter a DNS server with its fully qualified domain name (FQDN) as the service entry, it requires the DNS server used by the local computer to resolve the server dc01.contoso.com , but not the host dc02.microsoft.com . The DNS server dc01.contoso.com in turn can then resolve the host dc02.microsoft.com , and you will not see an error.

In other words, you can use the nslookup tool to reveal in great detail the weak points of your DNS resolution. To query multiple hosts one after another, use

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