Intro Linux Commands for DNS

DIG is used to query information about various DNS records, including host addresses, mail exchganges, and name servers, eg. “dig”.

Install dig on Linux (Optional)

Most modern Linux systems include the dig command.

Verify that it’s installed by checking the software version. To do so, open a command line and enter the following:

dig -v

The system should respond with a numeric code. If the system can’t find the command specified, install dig by entering the following:

Debian / Ubuntu:

sudo apt-get install dnsutils

CentOS / RedHat:

sudo yum install bind-utils

Once the installation finishes, verify the installation with the following command:

dig -v

How to Use the dig Command With Examples

Let’s look at the basic usage of the dig command.

Show canonical names (CNAMEs) or aliases that are associated with a domain name :

dig domain.tld cname

Show mail exchange records that are associated with a domaine name :

dig domain.tld mx

Show IPv6 addresses that are associated with a domain name :

dig domain.tld AAAA

Query a domain name associated with a specific IP address :

dig -x

Query for all records associated with a domaine name (A, AAAA, MX, NS, etc) :

host -v domain.tld 
host -a domain.tld

Configure system Domain Name System (DNS) resolver including local domain :

cat /etc/resolv.conf

Local listing of IP to hostnames. Takes precedence over DNS lookups :

cat /etc/hosts

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