dig is a
network administration
Network management is the process of administering and managing computer networks. Services provided by this discipline include fault analysis, performance management, provisioning of networks and maintaining quality of service. Network managem ...
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
The DNS root zone is the top-level DNS zone in the hierarchical namespace of the Domain Name System (DNS) of the Internet.
Before October 1, 2016, the root zone had been overseen by the Internet Corporation for Assigned Names and Numbers (ICANN ...
.
dig supports
Internationalized domain name
An internationalized domain name (IDN) is an Internet domain name that contains at least one label displayed in software applications, in whole or in part, in non-Latin script or alphabet or in the Latin alphabet-based characters with diacrit ...
(IDN) queries.
dig is a component of the domain name server software suite
BIND
BIND () is a suite of software for interacting with the Domain Name System (DNS). Its most prominent component, named (pronounced ''name-dee'': , short for ''name Daemon (computing), daemon''), performs both of the main DNS server roles, acting ...
. dig supersedes in functionality older tools, such as
nslookup and the program
host; however, the older tools are still used in complementary fashion.
Example usage
Basic
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 is the
time to live
Time to live (TTL) or hop limit is a mechanism which limits the lifespan or lifetime of data in a computer or network. TTL may be implemented as a counter (digital), counter or timestamp attached to or embedded in the data. Once the prescribed ev ...
value, which indicates the time of validity of the data.
The ''any'' DNS query is a special meta query which is now deprecated. Sinc
around 2019 most public DNS servers have stopped answering most DNS ''ANY'' queries usefull
RFC8482 - Saying goodbye to ANY
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:
$ dig wikimedia.org MX @ns0.wikimedia.org
; <<>> DiG 9.11.3 <<>> wikimedia.org MX @ns0.wikimedia.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39041
;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1024
; COOKIE: c9735311d2d2fa6e3b334ab01b67960d (good)
;; QUESTION SECTION:
;wikimedia.org. IN MX
;; ANSWER SECTION:
wikimedia.org. 3600 IN MX 10 mx1001.wikimedia.org.
wikimedia.org. 3600 IN MX 50 mx2001.wikimedia.org.
;; Query time: 1 msec
;; SERVER: 208.80.154.238#53(208.80.154.238)
;; WHEN: Sat Sep 18 21:33:24 PDT 2021
;; MSG SIZE rcvd: 108
With output formatting
There are man
output formatting optionsavailable. A common selection to make the output more terse is:
$ dig +noall +answer +multiline wikimedia.org MX
wikimedia.org. 3600 IN MX 10 mx1001.wikimedia.org.
wikimedia.org. 3600 IN MX 50 mx2001.wikimedia.org.
Where ''+noall +answer +multiline'' are simply output formatting flags.
History
dig was originally written by Steve Hotz and incorporated into
BIND
BIND () is a suite of software for interacting with the Domain Name System (DNS). Its most prominent component, named (pronounced ''name-dee'': , short for ''name Daemon (computing), daemon''), performs both of the main DNS server roles, acting ...
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".
See also
*
BIND
BIND () is a suite of software for interacting with the Domain Name System (DNS). Its most prominent component, named (pronounced ''name-dee'': , short for ''name Daemon (computing), daemon''), performs both of the main DNS server roles, acting ...
name server
*
Root name server – top-level name servers providing top level domain name resolution
*
List of DNS record types – possible types of records stored and queried within DNS
*
whois
*
host is a simple utility for performing Domain Name System lookups
*
nslookup, another utility that can be used to obtain similar information
References
Bibliography
* Paul Albitz and Cricket Liu. DNS and BIND, 5th Edition. Nutshell Series. O'Reilly and Associates, Inc., 2006.
External links
Official BIND 9 man page for digHow to use dig to query DNS name serversDig source code in ISC Gitlab repository
{{Unix commands
DNS software
Domain Name System
Free network-related software