Name Server Tools
A number of tools that are useful for debugging DNS are available in Linux under the bind-utils and whois packages. These tools are invaluable to administrators. Although some overlap exists between the tools, each has its advantages and disadvantages. The best way to compare them is to take a look at some of them. This will also give you the opportunity to check your name server setup.
The nslookup program performs name server lookups. The program has two modes, interactive and non-interactive. Two ways are available to enter interactive mode. The first way is to run nslookup with no arguments. The second way is to run nslookup with a hyphen (signifying input from the keyboard) and a name server. If nslookup is not given ...