The dig command in Linux is used to perform DNS lookups and query DNS servers. Here are some common ways to use dig.
First, install dig if it is not installed. See – https://www.geekdecoder.com/how-to-install-dig-utility-of-centos/
To query a specific DNS server for information about a domain name.
For example, to query the Google DNS server (8.8.8.8) for information about geekdecoder.com:
dig @8.8.8.8 geekdecoder.com
dig @8.8.8.8 geekdecoder.com
Output
dig @8.8.8.8 geekdecoder.com
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.13 <<>> @8.8.8.8 geekdecoder.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13730
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;geekdecoder.com. IN A
;; ANSWER SECTION:
geekdecoder.com. 14400 IN A 192.99.236.66
;; Query time: 31 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Tue Mar 14 14:25:57 UTC 2023
;; MSG SIZE rcvd: 60
To get more detailed information about a domain name.
dig domain-name
For example:
dig geekdecoder.com
Output
dig geekdecoder.com
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.13 <<>> geekdecoder.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46107
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;geekdecoder.com. IN A
;; ANSWER SECTION:
geekdecoder.com. 14400 IN A 192.99.236.66
;; Query time: 111 msec
;; SERVER: 67.207.67.3#53(67.207.67.3)
;; WHEN: Tue Mar 14 14:29:04 UTC 2023
;; MSG SIZE rcvd: 60
To query for a specific record type:
dig record-type domain-name
For example, to query for the mail servers (MX records) for geekdecoder.com:
dig MX geekdecoder.com
Output
dig MX geekdecoder.com
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.13 <<>> MX geekdecoder.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6621
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;geekdecoder.com. IN MX
;; ANSWER SECTION:
geekdecoder.com. 14400 IN MX 0 mail.geekdecoder.com.
;; Query time: 101 msec
;; SERVER: 67.207.67.3#53(67.207.67.3)
;; WHEN: Tue Mar 14 14:30:37 UTC 2023
;; MSG SIZE rcvd: 65
You can also combine options to get more specific results, such as:
dig +short A domain.com
This will return only the IP addresses (A records) for geekdecoder.com in a concise format.
dig +short A geekdecoder.com
Output
dig +short A geekdecoder.com
192.99.236.66
For more information about the dig command and its options, you can consult the dig manual page by typing man dig in the terminal.