MoinQ:

DNS/TCP/facebook.comについて、ここに記述してください。

/a.ns.c10r.facebook.com

$ dig z-p42-instagram.c10r.facebook.com. @a.gtld-servers.net

; <<>> DiG 9.12.1 <<>> z-p42-instagram.c10r.facebook.com. @a.gtld-servers.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62065
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 5
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;z-p42-instagram.c10r.facebook.com. IN  A

;; AUTHORITY SECTION:
facebook.com.           172800  IN      NS      a.ns.facebook.com.
facebook.com.           172800  IN      NS      b.ns.facebook.com.

;; ADDITIONAL SECTION:
a.ns.facebook.com.      172800  IN      AAAA    2a03:2880:fffe:c:face:b00c:0:35
a.ns.facebook.com.      172800  IN      A       69.171.239.12
b.ns.facebook.com.      172800  IN      AAAA    2a03:2880:ffff:c:face:b00c:0:35
b.ns.facebook.com.      172800  IN      A       69.171.255.12

;; Query time: 166 msec
;; SERVER: 192.5.6.30#53(192.5.6.30)
;; WHEN: Sun Apr 22 13:31:33 JST 2018
;; MSG SIZE  rcvd: 185

$ dig z-p42-instagram.c10r.facebook.com. @a.ns.facebook.com

; <<>> DiG 9.12.1 <<>> z-p42-instagram.c10r.facebook.com. @a.ns.facebook.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46010
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 5
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;z-p42-instagram.c10r.facebook.com. IN  A

;; AUTHORITY SECTION:
c10r.facebook.com.      3600    IN      NS      a.ns.c10r.facebook.com.
c10r.facebook.com.      3600    IN      NS      b.ns.c10r.facebook.com.

;; ADDITIONAL SECTION:
a.ns.c10r.facebook.com. 3600    IN      AAAA    2a03:2880:fffe:b:face:b00c:0:99
a.ns.c10r.facebook.com. 3600    IN      A       69.171.239.11
b.ns.c10r.facebook.com. 3600    IN      AAAA    2a03:2880:ffff:b:face:b00c:0:99
b.ns.c10r.facebook.com. 3600    IN      A       69.171.255.11

;; Query time: 34 msec
;; SERVER: 69.171.239.12#53(69.171.239.12)
;; WHEN: Sun Apr 22 13:32:09 JST 2018
;; MSG SIZE  rcvd: 185

$ dig z-p42-instagram.c10r.facebook.com. @69.171.239.11

; <<>> DiG 9.12.1 <<>> z-p42-instagram.c10r.facebook.com. @69.171.239.11
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32511
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 5
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;z-p42-instagram.c10r.facebook.com. IN  A

;; ANSWER SECTION:
z-p42-instagram.c10r.facebook.com. 60 IN A      31.13.82.174

;; AUTHORITY SECTION:
c10r.facebook.com.      3600    IN      NS      a.ns.c10r.facebook.com.
c10r.facebook.com.      3600    IN      NS      b.ns.c10r.facebook.com.

;; ADDITIONAL SECTION:
a.ns.c10r.facebook.com. 3600    IN      AAAA    2a03:2880:fffe:b:face:b00c:0:99
a.ns.c10r.facebook.com. 3600    IN      A       69.171.239.11
b.ns.c10r.facebook.com. 3600    IN      AAAA    2a03:2880:ffff:b:face:b00c:0:99
b.ns.c10r.facebook.com. 3600    IN      A       69.171.255.11

;; Query time: 34 msec
;; SERVER: 69.171.239.11#53(69.171.239.11)
;; WHEN: Sun Apr 22 13:33:28 JST 2018
;; MSG SIZE  rcvd: 201