I noticed .de domains were not resolving as expected. While debugging, it turns out some DNS servers of the denic seem to be out of sync.
This is a ``nice" query, created by resolving a well known domain on the denic nameservers:
---snip---
nihilus@zeus:~$ dig -t NS de
; <<>> DiG 9.5.1-P3 <<>> -t NS de
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61752
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 9
;; QUESTION SECTION:
;de. IN NS
;; ANSWER SECTION:
de. 86400 IN NS z.nic.de.
de. 86400 IN NS c.de.net.
de. 86400 IN NS l.de.net.
de. 86400 IN NS a.nic.de.
de. 86400 IN NS s.de.net.
de. 86400 IN NS f.nic.de.
;; ADDITIONAL SECTION:
a.nic.de. 2191 IN A 194.0.0.53
a.nic.de. 2191 IN AAAA 2001:678:2::53
c.de.net. 2191 IN A 208.48.81.43
f.nic.de. 2191 IN A 81.91.164.5
f.nic.de. 2191 IN AAAA 2001:608:6:6::10
l.de.net. 2191 IN A 77.67.63.105
l.de.net. 2191 IN AAAA 2001:668:1f:11::105
s.de.net. 2191 IN A 195.243.137.26
z.nic.de. 2191 IN A 194.246.96.1
;; Query time: 819 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed May 12 14:50:27 2010
;; MSG SIZE rcvd: 306
nihilus@zeus:~$ for i in a.nic.de c.de.net f.nic.de l.de.net s.de.net z.nic.de; do dig fefe.de @$i; done
; <<>> DiG 9.5.1-P3 <<>> fefe.de @
a.nic.de
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 9590
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;fefe.de. IN A
;; AUTHORITY SECTION:
de. 7200 IN SOA f.nic.de. its.denic.de. 2010051253 7200 7200 3600000 7200
;; Query time: 23 msec
;; SERVER: 2001:678:2::53#53(2001:678:2::53)
;; WHEN: Wed May 12 14:50:54 2010
;; MSG SIZE rcvd: 77
[...]
; <<>> DiG 9.5.1-P3 <<>> fefe.de @
z.nic.de
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 40763
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;fefe.de. IN A
;; AUTHORITY SECTION:
de. 7200 IN SOA f.nic.de. its.denic.de. 2010051253 7200 7200 3600000 7200
;; Query time: 12 msec
;; SERVER: 194.246.96.1#53(194.246.96.1)
;; WHEN: Wed May 12 14:50:54 2010
;; MSG SIZE rcvd: 77
---snip---
As you see, at least a.nic.de and z.nic.de return an NXDOMAIN for a registered and correctly configured domain.