Dig (command)

dig is a network administration command-line tool for querying the Domain Name System (DNS).

dig is useful for network troubleshooting and for educational purposes. It can operate based on command line option and flag arguments, or in batch mode by reading requests from an operating system file. When a specific name server is not specified in the command invocation, it uses the operating system's default resolver, usually configured in the file resolv.conf. Without any arguments it queries the DNS root zone.

dig supports Internationalized domain name (IDN) queries.

dig is a component of the domain name server software suite BIND. dig supersedes in functionality older tools, such as nslookup and the program host; however, the older tools are still used in complementary fashion.

Basic
In this example, dig is used to query for any type of record information in the domain example.com:

The number 172719 in the above example is the time to live value, which indicates the time of validity of the data.

The any DNS query is a special meta query which is now deprecated. Since around 2019, most public DNS servers have stopped answering most DNS ANY queries usefully.

If ANY queries do not enumerate multiple records, the only option is to request each record type (e.g. A, CNAME, or MX) individually.

Specific DNS server
Queries may be directed to designated DNS servers for specific records; in this example, MX records:

With output formatting
There are many output formatting options available. A common selection to make the output more terse is:

Where +noall +answer +multiline are simply output formatting flags.

History
dig was originally written by Steve Hotz and incorporated into BIND 4 since at least 1990; later it was rewritten by Michael Sawyer, and is maintained by the Internet Systems Consortium as part of BIND 9.

When originally written, the manual page for dig indicated that its name was an acronym for "Domain Information Groper". This expansion was removed in 2017; the tool's name is now simply "dig".