dig is basic command to fetch details from to nameservers

• Basic example: dig redhat.com
  • dig output has following section
    • Header: It has basic details like dig version and metadata about response.
    • Question section: It has the query we’ve asked for.
    • Answer section: Response given by the nameservers.
    • Authority section: It has the nameservers for the domains
    • Additional section: It lists the IP’s of nameservers.
• To fetch the shortned version of dig’s output
  • dig redhat.com +noall +answer +question
    • +noall : will not show any output
    • +answer : will show answer section
    • +question : will show question section
  • dig redhat.com +short
• List the MX record for the domain.
  • dig redhat.com MX +noall +answer +question
• List NS records for any domain.
  • dig redhat.com NS +noall +answer +question
• Resolve a domain record.
  • dig www.redhat.com +noall +answer +question

    $ > dig www.redhat.com +noall +answer +question
  
    ; <<>> DiG 9.8.3-P1 <<>> www.redhat.com +noall +answer +question
    ;; global options: +cmd
    ;www.redhat.com.			IN	A
    www.redhat.com.		3600	IN	CNAME	ds-www.redhat.com.edgekey.net.
    ds-www.redhat.com.edgekey.net. 13481 IN	CNAME	ds-www.redhat.com.edgekey.net.globalredir.akadns.net.
    ds-www.redhat.com.edgekey.net.globalredir.akadns.net. 3600 IN CNAME e3396.dscx.akamaiedge.net.
    e3396.dscx.akamaiedge.net. 20	IN	A	173.222.31.161
    

• Get response from specific nameserver.
  • dig @namserver_address domain_url: dig @ns2.redhat.com. www.redhat.com
• Get reverse dns i.e. get record from given ip.
  • dig -x @nameserver_address ip_addr: dig -x @ns.homebox.in 1.2.3.4 OR
  • dig -x ip_addr: dig -x 1.2.3.4