Find the DNS Authority Record for a DNS Domain (SOA)

Q.How do I find out the DNS authority record (SOA) for any DNS domain under UNIX / Linux shell?

A. You can easily find out (SOA) start of authority record using command such as dig or host under UNIX and Linux like operating systems. SOA specifies authoritative information about a DNS zone, including the primary name server, the email of the domain administrator, the domain serial number, and several timers relating to refreshing the zone.

Display SOA using host command

$ host -t soa {domain.com}
$ host -t soa cyberciti.com

Sample output:

cyberciti.com has SOA record ns1.nixcraft.net. vivek.nixcraft.com. 2009012202 10800 3600 604800 3600

Display SOA using dig command

$ dig SOA {domain.com}
$ dig SOA cyberciti.com

Sample output:

; <> DiG 9.5.0-P2 <> SOA cyberciti.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52962
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 3

;; QUESTION SECTION:
;cyberciti.com.			IN	SOA

;; ANSWER SECTION:
cyberciti.com.		10518	IN	SOA	ns1.nixcraft.net. vivek.nixcraft.com. 2009012202 10800 3600 604800 3600

;; AUTHORITY SECTION:
cyberciti.com.		1088	IN	NS	ns2.nixcraft.net.
cyberciti.com.		1088	IN	NS	ns1.nixcraft.net.
cyberciti.com.		1088	IN	NS	ns3.nixcraft.net.

;; ADDITIONAL SECTION:
ns3.nixcraft.net.	63071	IN	A	208.43.78.162
ns1.nixcraft.net.	156291	IN	A	208.43.138.52
ns2.nixcraft.net.	156291	IN	A	75.126.168.152

;; Query time: 226 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu Feb  5 11:44:40 2009
;; MSG SIZE  rcvd: 196

Replace cyberciti.com with your actual domain name for which you are trying to locate the DNS Authority.

Posted by: SXI ADMIN

The author is the creator of SXI LLC and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.