NSLookup Network Utility
The nslookup, or nameserver lookup, utility is used to find an IP address and associate it with a domain name. NSLookup is available for most major operating systems.
C:\>nslookup /?
Usage:
nslookup [-opt ...] # interactive mode using default server
nslookup [-opt ...] - server # interactive mode using 'server'
nslookup [-opt ...] host # just look up 'host' using default server
nslookup [-opt ...] host server # just look up 'host' using 'server'
If you type nslookup without any options, it opens an interactive prompt where you can issue commands. Type in a ? at the prompt and you will see the different options available:
C:\>nslookup Default Server: ns1.comporium.net Address: 208.104.244.45 > ? Commands: (identifiers are shown in uppercase, [] means optional) NAME - print info about the host/domain NAME using default server NAME1 NAME2 - as above, but use NAME2 as server help or ? - print info on common commands set OPTION - set an option all - print options, current server and host [no]debug - print debugging information [no]d2 - print exhaustive debugging information [no]defname - append domain name to each query [no]recurse - ask for recursive answer to query [no]search - use domain search list [no]vc - always use a virtual circuit domain=NAME - set default domain name to NAME srchlist=N1[/N2/.../N6] - set domain to N1 and search list to N1,N2, etc. root=NAME - set root server to NAME retry=X - set number of retries to X timeout=X - set initial time-out interval to X seconds type=X - set query type (ex. A,AAAA,A+AAAA,ANY,CNAME,MX,NS,PTR, SOA,SRV) querytype=X - same as type - set query class (ex. IN (Internet), ANY) [no]msxfr - use MS fast zone transfer ixfrver=X - current version to use in IXFR transfer request server NAME - set default server to NAME, using current default server lserver NAME - set default server to NAME, using initial server root - set current default server to the root ls [opt] DOMAIN [> FILE] - list addresses in DOMAIN (optional: output to FILE) -a - list canonical names and aliases -d - list all records -t TYPE - list records of the given RFC record type (ex. A,CNAME,MX,NS, PTR etc.) view FILE - sort an 'ls' output file and view it with pg exit - exit the program >
If you enter in a domain name or hostname at the prompt, it will use your current DNS server to determine the IP address:
> learnthat.com Server: ns1.comporium.net Address: 208.104.244.45 Non-authoritative answer: Name: learnthat.com Address: 72.51.34.96
NSlookup allows you to troubleshoot domain name server problems and problems resolving host names.
