権威DNSサーバーへの問い合わせでWARNING: recursion requested but not available

dig @abc.abc.abc.abc www.example.com ANY

www.example.com のネームサーバーのIP (ここでは abc.abc.abc.abc とした) を指定してdigしたとき、

; <<>> DiG 9.8.3-P1 <<>> @abc.abc.abc.abc www.example.com ANY
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: １１１１１
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;www.example.com.       IN  ANY

;; ANSWER SECTION:

...

WARNING: recursion requested but not available

こんなWARNINGがでた。

たいそう気持ちが悪いので、RD (recursion desired) bit が立たないようした。

$ dig +norecurse  @abc.abc.abc.abc www.example.com ANY

; <<>> DiG 9.8.3-P1 <<>> +norecurse @abc.abc.abc.abc www.example.com ANY
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11111
;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 1

;; QUESTION SECTION:
;www.example.com.       IN  ANY

;; ANSWER SECTION:

...

$ man dig

...

+[no]recurse
           Toggle the setting of the RD (recursion desired) bit in the query. This bit is set by default, which means dig normally sends
           recursive queries. Recursion is automatically disabled when the +nssearch or +trace query options are used.

...