Hi there !
This has been happening for the last few weeks while using Cloudflare DNS, occassionally a request will return a SERVFAIL for my domain name (candy-crush.fr) and then shortly after return the valid response.
I created a little monitor of my DNS to be sure that they are healthy, and all is running good.
Here the actual response from 1.1.1.1:
; <<>> DiG 9.10.6 <<>> candy-crush.fr @1.1.1.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 60
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1452
;; QUESTION SECTION:
;candy-crush.fr. IN A
;; Query time: 2235 msec
;; SERVER: 1.1.1.1#53(1.1.1.1)
;; WHEN: Thu Nov 29 15:03:34 CET 2018
;; MSG SIZE rcvd: 43
And the response from 8.8.8.8:
; <<>> DiG 9.10.6 <<>> candy-crush.fr @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40843
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;candy-crush.fr. IN A
;; ANSWER SECTION:
candy-crush.fr. 299 IN A 212.129.45.37
;; Query time: 49 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Thu Nov 29 15:05:02 CET 2018
;; MSG SIZE rcvd: 59
I can’t find any explanation about what is happening 