[dns-operations] A strange DNS problem (intermittent SERVFAILs)

[Paul Ebersman]

matthew-l> I wonder whether the first one (SERVFAIL for NS) is a clue.
matthew-l> bcpe.fr is delegated to the same servers which do not answer
matthew-l> NS queries.  Thus, NS RRSET is only available from the parent
matthew-l> (.fr) and not the child.  Maybe this upsets child-centric
matthew-l> resolvers.

Likely. Comcast is using nominum, which is parent-centric. Works on
their resolvers:

$ dig @75.75.75.75 banquepopulaire.fr ns

; <<>> DiG 9.12.2 <<>> @75.75.75.75 banquepopulaire.fr ns
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62340
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;banquepopulaire.fr.            IN      NS

;; ANSWER SECTION:
banquepopulaire.fr.     3600    IN      NS      dns2.bpce.fr.
banquepopulaire.fr.     3600    IN      NS      dns1.bpce.fr.

;; Query time: 367 msec
;; SERVER: 75.75.75.75#53(75.75.75.75)
;; WHEN: Sat May 30 11:30:55 MDT 2020
;; MSG SIZE  rcvd: 90