[Pdns-users] Problem with Linode NS Servers

[Brian Candler]

On 13/03/2025 14:59, rob777 via Pdns-users wrote:
>#
>
> My Powerdns Recursor cant resolve stuff from the NS Servers 
> ns1.linode.com <http://ns1.linode.com/> , ns2.linode.com 
> <http://ns2.linode.com/>, ns3.linode.com <http://ns3.linode.com/>
>
>#
>
>
You starting point should be to send test DNS queries directly there. On 
your pdns server:

dig +norec @ns1.linode.com alpinelinux.org a

Repeat this several times.

1. do you get any reply?
2. is the reply authoritative (aa flag present) ?
3. are the answers consistent between successive queries (apart from 
ordering of RRs), and is the TTL the same?

 From here I get:

# dig +norec @ns1.linode.com alpinelinux.org a

; <<>> DiG 9.18.30-0ubuntu0.22.04.2-Ubuntu <<>> +norec @ns1.linode.com 
alpinelinux.org a
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30452
;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1024
;; QUESTION SECTION:
;alpinelinux.org.        IN    A

;; ANSWER SECTION:
alpinelinux.org.    3600    IN    A    213.219.36.190

;; AUTHORITY SECTION:
alpinelinux.org.    3600    IN    NS    ns5.linode.com.
alpinelinux.org.    3600    IN    NS    ns4.linode.com.
alpinelinux.org.    3600    IN    NS    ns3.linode.com.
alpinelinux.org.    3600    IN    NS    ns1.linode.com.
alpinelinux.org.    3600    IN    NS    ns2.linode.com.

;; Query time: 6 msec
;; SERVER: 2600:14c0:6::2#53(ns1.linode.com) (UDP)
;; WHEN: Thu Mar 13 18:15:57 UTC 2025
;; MSG SIZE  rcvd: 160

If you get no reply at all in point (1), then *maybe* linode are 
blocking your DNS traffic. Or there is a network routability issue 
between you and them. Try with traceroute, and raise the issue with 
*your* provider.

If you get a reply but it doesn't look what I showed above, then there 
is something between you and the Internet which is mangling your DNS, 
e.g. some sort of inline proxy - in which case, this is a networking 
issue that you have to take upstream, nothing to do with PDNS.

It could also be a problem resolving "ns1.linode.com", which it has to 
do before sending the query there. Does that resolve? Try:

dig +short @8.8.8.8 ns1.linode.com. a

then repeat the original query with the IP address returned:

dig +norec @x.x.x.x alpinelinux.org a

Happy debugging!

Brian.
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