How to use "dig" utility to debug DNS

This note was created on 2024-04-02
This note was last edited on 2024-04-24

=== Usage ===
Check MX record for "example.com":
$ dig example.com mx

Perform a DNS lookup for the A records of "example.com" and display only answer section in short format:
$ dig example.com a +short

Perform a DNS lookup for the A (IPv4 address) records of "example.com" and display only the answer section:
$ dig example.com a +noall +answer

Check CNAME record for "www.example.com" using specific DNS server:
$ dig www.example.com cname @9.9.9.9

Check CNAME record for "www.example.com" using specific DNS server via DOT:
$ dig www.example.com cname @9.9.9.9 +tls

Check CNAME record for "www.example.com" using specific DNS server via DOH:
$ dig www.example.com cname @dns.quad9.net +https

Perform a reverse DNS lookup for the IP address "9.9.9.9":
$ dig -x 9.9.9.9

Query authoritative DNS:
$ dig +nssearch example.com

Check DNSSEC:
$ dig +dnssec example.com

Display the full trace of the DNS query for MX record:
$ dig +trace example.com mx @9.9.9.9