Use apt-get or yum to install DIG (and other DNS utilities).

[root@server1 ~]# yum install bind-utils

The DIG command followed by a domain name will display information about the domain name, such as the A record (IPv4 address) of the domain. The QUESTION SECTION is simply the lookup you are performing, and the ANSWER SECTION is the answer to the question. The AUTHORITY SECTION lists the name servers that are being used.

[root@server1 ~]# dig www.example.com
. . .
;; QUESTION SECTION:
;www.example.com            IN    A

;; ANSWER SECTION:
www.example.com.     875    IN    A     93.184.216.34

;; AUTHORITY SECTION:
example.com.		6728	IN	  NS	a.iana-servers.net.
example.com.		6728	IN	  NS	b.iana-servers.net.
. . .

Reverse lookup

The -x option can be used to do a reverse lookup, to resolve an IP address to a hostname.

[root@server1 ~]# dig -x 12.34.56.78
. . . 
;; ANSWER SECTION:
87.65.43.21.in-addr.arpa.  86400  IN    PTR    cpe-87-65-43-21.example.com.
. . .

Answer section

Typically, only the ANSWER SECTION is needed. The following options can be appended to only display the ANSWER SECTION.

[root@server1 ~]# dig www.example.com +nocomments +noquestion +noauthority +noadditional +nostats
. . .
www.example.com.      875      IN     A     93.184.216.34

The same can be accomplished using the following options.

[root@server1 ~]# dig www.example.com +noall +answer
. . .
www.example.com.      875      IN     A     93.184.216.34

IP address only

The +short option can be used to only display the IP addresss from the ANSWER SECTION.

[root@server1 ~]# dig www.example.com +short
93.184.216.34

MX records

The MX or -t MX option can be used to add the mail records to the output.

[root@server1 ~]# dig www.example.com MX
. . . 
;; ANSWER SECTION:
www.example.com.      875      IN     A     93.184.216.34
example.com           900      IN     MX    5 mx1.example.com.
example.com           900      IN     MX    10 mx2.example.com.
. . .

NS records

The NS or -t NS option can be used to add the name servers to the output.

[root@server1 ~]# dig www.example.com NS
. . . 
;; ANSWER SECTION:
www.example.com.      875      IN     A     93.184.216.34
example.com           900      IN     NS    ns1.domaincontrol.com.
example.com           900      IN     NS    ns1.domaincontrol.com.
. . .

SOA

The SOA or -t SOA option can be used to display the Start of Authority.

[root@server1 ~]# dig www.example.com SOA
. . . 
;; AUTHORITY SECTION:
example.com.       60     IN     SOA     sns.dns.icann.org noc.dns.icann.org 201611078 7200 3600 1209600 3600
. . .

Use a different nameserver

Instead of using the DNS server in /etc/resolv.conf, the @ character followed by the IP address of the nameserver you would like to use can be used to use an alternate nameserver. In this example, Google's 8.8.8.8 nameserver is used.

[root@server1 ~]# dig @8.8.8.8 www.example.com
. . .
;; ANSWER SECTION:
www.example.com.      875      IN     A     93.184.216.34
. . .

Use a preferred interface

The machine may have two or more interfaces. For example, let's say eth0 has IP address 192.168.0.100, and eth1 has IP address 10.0.0.100. The -b option can be used to select the interface to use.

[root@server1 ~]# dig -b 192.168.0.100 www.example.com
. . .
;; QUESTION SECTION:
;www.example.com               IN     A

;; ANSWER SECTION:
www.example.com.      875      IN     A     93.184.216.34
. . .