How to Retrieve DNS Information Using Dig

dig is a command-line DNS diagnostic tool from BIND. It retrieves and displays various DNS properties of a hostname or IP address, such as its DNS records and authoritative name servers.

Installing dig

You can install dig on most operating systems by downloading the latest version of BIND 9 from BIND’s trang web, or from the command line using a package manager. Click your operating system’s tab below lớn view instructions on how lớn install dig.

Windows

To install dig for Windows, go lớn BIND’s trang web and tải về the most current version of BIND 9. Extract the downloaded tệp tin and double-click the BINDinstall icon in the newly created directory.

On the BIND 9 Installer screen, verify that the target directory is phối lớn C:\Program Files\ISC BIND 9 (or C:\Program Files (x86)\ISC BIND 9 if you are using an x86 architecture) and select the Tools Only kiểm tra box. Then click Install.

Once you’ve installed BIND 9, you need lớn add BIND lớn your system’s paths lớn make dig available from the command line. To add the path lớn your system, open the Windows Control Panel and then open your System Properties. In the Advanced tab, click Environment Variables.

Under System Variables, select the Path variable and then click Edit.

In the Edit environment variable screen, click New and enter the new path C:\Program Files\ISC BIND 9\bin (or C:\Program Files (x86)\ISC BIND 9 if you are using an x86 architecture). Once you’ve added the path, click OK.

In the Edit Variables window, click OK. In the System properties window, click OK.

Once you’ve added the path variable, open a new Command Prompt window and verify dig’s installation by running the dig -v command. dig should return version information about itself. If the command returns anything other phàn nàn version information, verify your path variable configuration.

macOS

dig is usually installed by mặc định on macOS systems and you can access it from the Terminal command line with no additional installation. Run the dig -v command in Terminal lớn verify dig’s installation. If the command returns anything other phàn nàn dig’s version information, you need lớn install BIND.

To install BIND on macOS using Homebrew, first verify Homebrew’s installation by running the following command:

brew -v

If the command returns anything other phàn nàn brew’s version information, you may need lớn install Homebrew.

To install Homebrew, use the following command:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Once you’ve installed Homebrew, use the following command lớn install BIND:

brew install bind

Once you’ve installed BIND, run rẩy the dig -v command again lớn verify dig’s installation.

Linux

dig is usually installed by mặc định on Linux systems and you can accessed it from the command line with no additional installation. Run the dig -v command lớn verify dig’s installation. If the command returns anything other phàn nàn dig’s version information, you may need lớn install dnsutils.

To install dnsutils on Linux using apt-get, run rẩy the following commands:

sudo apt-get update
sudo apt-get install dnsutils

Once you’ve installed dnsutils, run rẩy the dig -v command again lớn verify dig’s installation.

Common dig Commands

Below are some common dig commands lớn retrieve DNS information about a hostname. You can run rẩy any of the following examples in a terminal lớn see the output:

Command	Example	Description
`dig`	`dig example.com`	Returns the A records found at a hostname.
`dig any`	`dig example.com any`	Returns all records for a hostname, including NS and SOA records.
`dig @`	`dig @ns1.digitalocean.com example.com MX`	Queries a hostname’s name server directly instead of your ISP’s resolver. Include the record type parameter lớn retrieve records of a specific type at a hostname. DigitalOcean’s name server addresses are: ns1.digitalocean.com, ns2.digitalocean.com, and ns3.digitalocean.com
`dig`	`dig example.com NS`	Only returns the records of a specified type at a hostname.
`dig +short`	`dig example.com +short`	Only returns the IP addresses for all A records at a hostname.
`dig +trace`	`dig example.com +trace`	Adding `+trace` instructs dig lớn resolve the query from the root name server and return information from each server queried in the delegation chain.

dig commands return one or multiple sections of information about the hostname’s DNS records depending on the syntax of your query. In the example below, dig returned results for the query dig example.com:

; <<>> DiG 9.10.6 <<>> example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50169
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 5

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION
;example.com.			IN	A

;; ANSWER SECTION:
example.com.		6108	IN	A	93.184.216.34

;; AUTHORITY SECTION:
example.com.		52437	IN	NS	b.iana-servers.net.
example.com.		52437	IN	NS	a.iana-servers.net.

;; ADDITIONAL SECTION:
a.iana-servers.net.	195	IN	A	199.43.135.53
a.iana-servers.net.	195	IN	AAAA	2001:500:8f::53
b.iana-servers.net.	195	IN	A	199.43.133.53
b.iana-servers.net.	195	IN	AAAA	2001:500:8d::53

The most relevant sections for users tend lớn be the following:

Question Section: A reaffirmation of the query made lớn the DNS. In the example above, dig queried the hostname example.com and requested information about the hostname’s A records.
Answer Section: The records returned by the query. The answer section usually contains the most relevant information for dig users. In the example above, dig returned the A record for the IP address 204.13.248.106.
Authority Section: The authoritative name servers that host the hostname’s records. This can be helpful in verifying a hostname’s current delegation. For more information about how lớn delegate your hostname lớn point at DigitalOcean’s name servers, see our community tutorial.
Additional Section: Any extra information the resolver may have passed along with the answer. In the example above, the resolver passed along the IP addresses for example.com’s name servers in addition lớn the answer of the original query.