Une autre indispo d'au moins plusieurs heures au mois de septembre ou octobre 2013 chépu. Le problème a été mentionné sur le facebook de dot.tk.

% dig mauvaispourlesyeux.tk

; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> mauvaispourlesyeux.tk
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 21828
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mauvaispourlesyeux.tk.		IN	A

;; Query time: 50 msec
;; SERVER: 194.2.0.20#53(194.2.0.20)
;; WHEN: Mon Apr 15 18:47:20 2013
;; MSG SIZE  rcvd: 39

% dig tzii.tk              

; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> tzii.tk
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21875
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 4, ADDITIONAL: 8

;; QUESTION SECTION:
;tzii.tk.			IN	A

;; ANSWER SECTION:
tzii.tk.		300	IN	A	93.170.52.21
tzii.tk.		300	IN	A	93.170.52.31

;; AUTHORITY SECTION:
tk.			86400	IN	NS	a.ns.tk.
tk.			86400	IN	NS	b.ns.tk.
tk.			86400	IN	NS	c.ns.tk.
tk.			86400	IN	NS	d.ns.tk.

;; ADDITIONAL SECTION:
a.ns.tk.		10800	IN	A	194.0.38.1
b.ns.tk.		10800	IN	A	194.0.39.1
c.ns.tk.		10800	IN	A	194.0.40.1
d.ns.tk.		10800	IN	A	194.0.41.1
a.ns.tk.		10800	IN	AAAA	2001:678:50::1
b.ns.tk.		10800	IN	AAAA	2001:678:54::1
c.ns.tk.		10800	IN	AAAA	2001:678:58::1
d.ns.tk.		10800	IN	AAAA	2001:678:5c::1

;; Query time: 73 msec
;; SERVER: 194.2.0.20#53(194.2.0.20)
;; WHEN: Mon Apr 15 18:47:35 2013
;; MSG SIZE  rcvd: 300

% dig +trace mauvaispourlesyeux.tk

; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> +trace mauvaispourlesyeux.tk
;; global options: +cmd
;; Received 12 bytes from 194.2.0.20#53(194.2.0.20) in 66 ms

% dig +trace tzii.tk              

; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> +trace tzii.tk
;; global options: +cmd
;; Received 12 bytes from 194.2.0.20#53(194.2.0.20) in 59 ms

D'après http://networking.ringofsaturn.com/Unix/dnstroubleshooting.php

SERVFAIL / SERVFAIL means that the domain does exist and the root name servers have information on this domain, but that the authoritative name servers are not answering queries for this domain.

Peu de temps après,

dig mauvaispourlesyeux.tk       

; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> mauvaispourlesyeux.tk
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23417
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mauvaispourlesyeux.tk.		IN	A

;; ANSWER SECTION:
mauvaispourlesyeux.tk.	300	IN	A	178.33.43.220

;; Query time: 130 msec
;; SERVER: 194.2.0.20#53(194.2.0.20)
;; WHEN: Mon Apr 15 18:53:03 2013
;; MSG SIZE  rcvd: 55

Voir aussi: http://stackoverflow.com/questions/3051035/dns-dig-command-line-tool-returns-status-servfail-should-i-be-worried

… qui a durée à peu près 4 ou 5h.

Le site tzii.tk était accessible. Mais pas un autre .tk également utilisé pour tester.