Subj : ipv6 resolvability
To   : All
From : David Gonzalez
Date : Sat Nov 16 2024 22:18:58

   Hello Michiel!

13 Nov 24 13:39, you wrote to Floris van Unen:

Its great to see progress on enabling IPv6 for your nameservers, Floris! Adding AAAA records and updating the glue records is a smart move to enhance IPv6 compatibility.

Regarding your question on IPv6 fallback behavior: If a DNS client (resolver) attempts to resolve a domain over IPv6 and finds that none of the authoritative nameservers for that domain have an IPv6 address, it will indeed fall back to IPv4, provided the client has IPv4 connectivity and the domains nameservers are reachable over IPv4. This fallback ensures accessibility for IPv4-only or mixed IPv4/IPv6 environments but doesnt fully support the vision of an IPv6-only future.

As MV pointed out, preparing for an IPv6-only environment is crucial. While many current nameservers still offer AAAA records over IPv4, native IPv6 access for your nameservers ensures seamless support as networks continue moving towards IPv6-exclusive setups. Additionally, by having both IPv4 and IPv6 connectivity, you improve redundancy and are better positioned to handle requests from diverse client networks.

Using sites like http://test-ipv6.com and https://ipv6-test.com is a fantastic way to confirm full IPv6 functionality. These tools not only check your IPv6 reachability but also evaluate DNS resolution to verify whether queries return IPv6 addresses where available. Its worth checking them out post-configuration to verify everything is set up correctly.

Nice work on pushing IPv6 adoption forward!


 MV> Hello Floris,

 MV> On Wednesday November 13 2024 13:20, you wrote to All:

 FU>> with help of https://internet.nl/site/fido.unen.net/3038781/ i
 FU>> found out that none of my nameservers supported ipv6 so i added
 FU>> ipv6 AAAA records for the nameservers and updated the glue
 FU>> records and now it's better.

 MV> Great!

 MV> So what do http://test-ipv6.com and https://ipv6-test.com say?

 FU>> So does a recursive DNS query fallback into ipv4 if none of the
 FU>> nameservers for a domain have an ipv6 address? Because people
 FU>> could still find my ipv6 AAAA record on my ipv4-only
 FU>> nameservers...

 MV> Don't confuse the accesability with the content of name servers. Most
 MV> name servers that are accesible by IPv4 only do respond with an AAAA
 MV> record when that is present for the requested host.

 MV> But of course we should all prepare to function in an IPv6 only
 MV> environment, so the use of name servers that are accesable via IPv6 is
 MV> much preferred.


 MV> Cheers, Michiel

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David

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