old rDNS entries not deleted when someone deletes their tunnel?

[hlinden]

Hello Forum,

I posted this a few minutes ago over in "General Discussion" and thought about it under the shower for a few minutes, so it seems more fit to post here now. Sorry for the crosspost, I deleted the other one:

I only set up my HE-tunnel yesterday and I simply forgot to set the rDNS-entries for my subnet (2001:470:1f0b:114c::/64), so there were none. Well, there should have been none, as I understand it, but instead this happened:

Code Select Expand

hlinden@espresso ~ $ dig -x 2001:470:1f0b:114c::1

; <<>> DiG 9.9.3-P2 <<>> -x 2001:470:1f0b:114c::1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 65126
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 4

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.c.4.1.1.b.0.f.1.0.7.4.0.1.0.0.2.ip6.arpa. IN PTR

;; ANSWER SECTION:
1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.c.4.1.1.b.0.f.1.0.7.4.0.1.0.0.2.ip6.arpa. 0 IN PTR ip6.todd.heikendorf-server.de.

;; AUTHORITY SECTION:
c.4.1.1.b.0.f.1.0.7.4.0.1.0.0.2.ip6.arpa. 3860 IN NS ns1.ntdns.de.
c.4.1.1.b.0.f.1.0.7.4.0.1.0.0.2.ip6.arpa. 3860 IN NS ns2.ntdns.de.
c.4.1.1.b.0.f.1.0.7.4.0.1.0.0.2.ip6.arpa. 3860 IN NS ns3.ntdns.de.

;; ADDITIONAL SECTION:
ns1.ntdns.de. 446 IN A 62.141.32.2
ns2.ntdns.de. 446 IN A 62.141.34.2
ns3.ntdns.de. 446 IN A 62.241.33.128

;; Query time: 31 msec
;; SERVER: 131.234.137.23#53(131.234.137.23)
;; WHEN: Mon Nov 04 12:46:52 CET 2013
;; MSG SIZE  rcvd: 252




I noticed, when a traceroute6 resolved my router as "ip6.todd.heikendorf-server.de".

I've set the rDNS-entries for my subnet to the he.net DNS-servers now, so once the TTL of this entries is gone it should  work correctly, but how can this happen in the first place?

Could it be that someone had that subnet before me and when he deleted the tunnel you didn't remove the rDNS entries?