Nslookup is an administrative command-line tool for troubleshooting and testing DNS servers. It is installed alongside the protocol of TCP/IP through a Control Panel. In order to use Nslookup, there are several tips that should be noted:
- The protocol of TCP/IP requires to be installed while running as Nslookup.exe on the system.
- A single DNS server is at least required to be defined in the field of the Service Searching Order of the DNS tab in the Properties page of Microsoft TCP/IP.
- Nslookup always devolves the name derived from the latest context. Failure for name queries to be fully qualified results in the query being attached to the present context. A perfect example is the present DNS settings, which are att.com while performing a query on www.microsoft.com; the initial query goes out as www.microsoft.com.att.com since it is unqualified. This may be an inconsistent behavior in regard to other vendor Nslookup versions.
- Nslookup.exe is run in non-interactive and interactive modes. Non-interactive mode is handy when only one data piece requires being returned.
- Nslookup.exe may be started in the interactive mode by simply typing “Nslookup” on the command prompt:
- Typing “?” or “help” or on the command prompt generates lists of obtainable commands.
- For interactive commands to be interrupted, press CTRL+C.
- For an interactive mode to be exited followed by a return to the prompt command, Exit should be typed on the command prompt.
- Various varieties of options are capable of being set in Nslookup.exe by running at the command prompt’s set command.
- To obtain these options’ complete listing requires typing set all.
Looking up Dissimilar Data Types
For different types of data to be looked up within the name space of the domain, use: the command prompt’s set query type or set type command. Making the initial query for remoter names results in an authoritative answer while subsequent queries results non-authoritative answers. Similarly, the initial querying of the remote host results in the respective DNS server contacting the authoritative DNS server of that domain.
Direct Querying from Different Name Server
When directly querying from different name servers, lserver or server commands should be used to switch to this name server. lserver commands make use of local servers with an aim of getting the server’s address in order to switch to, whereas server commands use the present default server for getting the address. For excellent testing and troubleshooting of DNS serves, the nslookup utility comes in handy.