nslookup : Networking

When nslookup is started, it displays the current hostname and the IP address of the locally configured DNS server. You will then see a command prompt which allows you to specify further queries. This is known as 'interactive' mode. The commands you can enter in interactive mode are listed in Table 10.

Table 10 nslookup Switches
Switch	Description
all	Prints options, as well as current server and host information
[no]debug	Prints debugging information
[no]d2	Prints exhaustive debugging information
[no]defname	Appends the domain name to each query
[no]recurse	Asks for recursive answer to query
[no]search	Uses domain search list
[no]vc	Always uses a virtual circuit
domain=NAME	Sets default domain name to NAME
srchlist=N1[/N2/.../N6]	Sets domain to N1 and search list to N1, N2, and so on
root=NAME	Sets root server to NAME
retry=X	Sets number of retries to X
timeout=X	Sets initial timeout interval to X seconds
type=X	Sets query type (for example, A, ANY, CNAME, MX, NS, PTR, SOA, or SRV)
querytype=X	Same as type
class=X	Sets query class (for example, IN [Internet], ANY)
[no]msxfr	Uses MS fast zone transfer
ixfrver=X	Current version to use in IXFR transfer request
server NAME	Sets default server to NAME, using current default server
exit	Exits the program

Instead of using interactive mode, you can also execute nslookup requests directly at the command prompt. The following listing shows the output from nslookup when a domain name is specified to be resolved.

C:\>nslookup comptia.org
Server:  nsc1.ht.ok.shawcable.net
Address:  64.59.168.13
Non-authoritative answer:
Name:    comptia.org
Address:  208.252.144.4

As you can see from the output, nslookup shows the hostname and IP address of the DNS server against which the resolution was performed, along with the hostname and IP address of the resolved host.