dig is a command-line client that allows you to make queries against DNS servers, which are servers that provide the Internet name service. While querying DNS servers is part of most Internet based applications (like web browsers, chat clients, email tools and so forth), those queries are done by the clients in the background, and without any user intervention. dig allows you to make such queries explicitly from the command-line. This is usually interesting for people that maintain DNS servers and want to test them, or network administrators that want to inspect name resolution in a particular network.
dig is part of the BIND software package, which runs on POSIX platforms, but ports to the Windows platform exist. An alternative tool is
nslookup, but dig is usually preferred for its better configurability and scriptability.
This tag should be added to questions that explicitly refer to the dig tool and its workings. Related tags are