Sticky old nameservers

[Andreas Schwarz]

Hi Stephane,

die you check the output from

unbound-control lookup assemblee-nationale.fr

?

I occasionally have similar issues with my setup when a domain changes its nameservers. If I recall correctly, this is due to the domain's old nameserver to be asked being cached. The command from above may show the issue.

Cheers

Am 19. Februar 2020 09:07:44 MEZ schrieb Stephane Bortzmeyer via Unbound-users <unbound-users at lists.nlnetlabs.nl>:
>I thought I knew the DNS but apparently I don't.
>
>Yesterday, around 1030 UTC the domain assemblee-nationale.fr had an
>issue: the IP address of its nameservers changed. The "new"
>nameservers served a different NS set. The problem is now fixed since
>yesterday, around 1200 UTC . The TTL of the wrong information was only
>300 seconds. Therefore, it should have disappeared by now. But it is
>not the case:
>
>% dig NS assemblee-nationale.fr
>
>; <<>> DiG 9.11.5-P4-5.1-Debian <<>> NS assemblee-nationale.fr
>;; global options: +cmd
>;; Got answer:
>;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56522
>;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
>
>;; OPT PSEUDOSECTION:
>; EDNS: version: 0, flags: do; udp: 4096
>;; QUESTION SECTION:
>;assemblee-nationale.fr.	IN NS
>
>;; ANSWER SECTION:
>assemblee-nationale.fr.	300 IN NS ns1432.ztomy.com.
>assemblee-nationale.fr.	300 IN NS ns2432.ztomy.com.
>
>;; Query time: 495 msec
>;; SERVER: ::1#53(::1)
>;; WHEN: Wed Feb 19 09:01:12 CET 2020
>;; MSG SIZE  rcvd: 102
>
>The correct NS set is ns{0,1,2}.fr.claradns.net, as you can see in the
>delegation (which did not change). Why is it not picked?
>
>It is as if the resolver does not return to the parent and, when the
>TTL expires, queries again the wrong nameservers.
>
>[::1 is Unbound Version 1.9.0 linked libs: libevent 2.1.8-stable (it
>uses epoll), OpenSSL 1.1.1d  10 Sep 2019]
>
>[Restarting Unbound solves the problem.]
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