About dig output reading

[Karan]

Hi,
I have some questions about the output reading of "dig" utility.

When I executed "dig @202.42.239.6 mydomain.com. any", the system
gives the output consists of a word "AUTHORITY: 2" but sometime it
stated as "AUTHORITY: 0".

Could somebody explain what is meant by "AUTHORITY: 2" and "AUTHORITY:
0"? What is the implication? Thanks.

; <<>> DiG 9.2.1 <<>> @202.42.239.6 mydomain.com. any
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35022
;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;mydomain.com.                       IN      ANY


=================
; <<>> DiG 9.2.1 <<>> @202.42.239.6 mydomain.com. any
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35022
;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 2

;; QUESTION SECTION:
;mydomain.com.                       IN      ANY