Mismatch AAAA records and DNS

#1

Hi there,

First of all thank you for your service, it is so much needed now all ISPs are switching to dual stack lite.

I have a dns zone that worked like a charm until yesterday:

  • the website is working fine: I can see the records of the DNS zone and they are being updated every day (when my ISP changes the IPv6 prefix)
  • none of the DNS server however seem to know any of the records of my dns zone

First time I noticed was yesterday, maybe the problem is happening since a longer time.

This is what the interface shows me: the prefix update is happening periodically (~once a day) and seems to be working fine:

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This is the reply of the DNS servers (the 3 of them have the same type of answer). The record r-pi4-8.yayimorphology.dynv6.net exists since several weeks already:

% nslookup r-pi4-8.yayimorphology.dynv6.net ns1.dynv6.com
Server:         ns1.dynv6.com
Address:        2a01:4f9:c010:95b::#53

*** Can't find r-pi4-8.yayimorphology.dynv6.net: No answer

Of course, I tried other DNS servers (Google) and none of them seem to know the record anymore, and it seems that no entry on the full zone are known to the DNS servers.

Can anyone help me there?

#2

I can not confirm:

nslookup r-pi4-8.yayimorphology.dynv6.net 8.8.8.8
Server:  dns.google
Address:  8.8.8.8

Name:    r-pi4-8.yayimorphology.dynv6.net
Address:  2001:16b8:5ce0:70ff:dea6:32ff:feb7:cac6

and:

nslookup yayimorphology.dynv6.net 8.8.8.8
Server:  dns.google
Address:  8.8.8.8

Name:    yayimorphology.dynv6.net
Address:  2001:16b8:5a01:ad2c:7eff:4dff:fead:c53f

However, the subdomains are not updated. I assume your entries are

Name                              Data
r-pi4-8.yayimorphology.dynv6.net  2001:16b8:5ce0:70ff:dea6:32ff:feb7:cac6

and

Name                              Data
test.yayimorphology.dynv6.net     2001:16b8:5ce0:70ff:bae8:56ff:fe24:397e

but should read

Name                              Data
r-pi4-8.yayimorphology.dynv6.net  ::7eff:4dff:fead:c53f

and

Name                              Data
test.yayimorphology.dynv6.net     ::bae8:56ff:fe24:397e

Was that the problem?

#3

Thank you for checking!

As far as I know/understand, the entries are correct: whenever I put the MAC address for data, I end up with a full IPv6 (if this is what you mean) on the web interface and an update on the prefix just updates everything (If this is what you mean?).

However about the nslookup:

  • trying on my ubuntu box yields me the right result from the server 8.8.8.8
  • trying from my android phone with the DNS client “AndroDNS” does not return anything
  • trying from my macOS does not return me anything

… now that I have confirmation it works on someone’s else computer, turns out that:

  • the AndroDNS client had to be switched explicitly to AAAA records
  • the nslookup on macOS suddenly decided to defaults to A records,
% nslookup                                  
> set type=AAAA
> r-pi4-8.yayimorphology.dynv6.net 
Server:         2001:16b8:5ce0:70ff::1
Address:        2001:16b8:5ce0:70ff::1#53

Non-authoritative answer:
r-pi4-8.yayimorphology.dynv6.net        has AAAA address 2001:16b8:5ce0:70ff:dea6:32ff:feb7:cac6

Still cannot access my raspberry from my smart phone, something is blocking the traffic, but does not seem to be because of the DNS.
Sorry for the false alarm!

#4

Don’t worry, that’s what the community is for.

Yes. However, the prefix should actually be identical, which it is not in the figure. Hence my assumption. With linux computers it doesn’t matter whether you enter the MAC address or the host part, with windows it has to be the host part.

Clicking on the Data heading toggles the display in the web interface.

Sometimes the router also causes problems with DNS resolution. Therefore, you should always try 8.8.8.8 (or 1.1.1.1) with nslookup.

#5

Yes. However, the prefix should actually be identical, which it is not in the figure.

Yes, sorry for the confusion:

  • the machines r-pi4-8.yayimorphology.dynv6.net and test.yayimorphology.dynv6.net are the 2 ones that have the prefix update + MAC address in place
  • the other entry yayimorphology.dynv6.net is pointing somewhere else outside of that network, and the update procedure is a full IPv6

So this is normal behaviour.

Sometimes the router also causes problems with DNS resolution. Therefore, you should always try 8.8.8.8 (or 1.1.1.1) with nslookup.

Indeed! That and the fact that nslookup was looking for an A record really confused me. In that respect, the test you made saved me a lot of time, thanks a lot for that!