dig (domain information groper) is a network administration command-line tool for querying Domain Name System (DNS) name servers.
dig is useful for network troubleshooting and for educational purposes. dig can operate in interactive command line mode 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 will use the operating systems default resolver, usually configured via the resolv.conf file. Without any arguments it queries the DNS root zone.
dig supports Internationalized Domain Name (IDN) queries.
dig is part of the BIND domain name server software suite. dig replaces older tools such as nslookup and the host program.
Example usage
In this example, dig is used to query for any type of record information in the domain example.com:
$ dig example.com any ; <<>> DiG 9.6.1 <<>> example.com any ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4016 ;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;example.com. IN ANY ;; ANSWER SECTION: example.com. 172719 IN NS a.iana-servers.net. example.com. 172719 IN NS b.iana-servers.net. example.com. 172719 IN A 208.77.188.166 example.com. 172719 IN SOA dns1.icann.org. hostmaster.icann.org. 2007051703 7200 3600 1209600 86400 ;; Query time: 1 msec ;; SERVER: ::1#53(::1) ;; WHEN: Wed Aug 12 11:40:43 2009 ;; MSG SIZE rcvd: 154
The number 172719 in the above example represents the Time to live value.
Queries may be directed to designated DNS servers for specific records; in this example, MX records:
$ dig wikimedia.org MX @ns0.wikimedia.org ; <<>> DiG 9.6.1 <<>> wikimedia.org MX @ns0.wikimedia.org ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61144 ;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 2 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;wikimedia.org. IN MX ;; ANSWER SECTION: wikimedia.org. 3600 IN MX 10 mchenry.wikimedia.org. wikimedia.org. 3600 IN MX 50 lists.wikimedia.org. ;; ADDITIONAL SECTION: mchenry.wikimedia.org. 3600 IN A 208.80.152.186 lists.wikimedia.org. 3600 IN A 91.198.174.5 ;; Query time: 73 msec ;; SERVER: 208.80.152.130#53(208.80.152.130) ;; WHEN: Wed Aug 12 11:51:03 2009 ;; MSG SIZE rcvd: 109
