[supriyo-biswas]

This “human usable” argument gets trotted out so much on here and elsewhere, but the same people would be surprised to know about HTTP/2, TLS and the like, which by that definition, isn’t human usable either because of binary formats and encryption.

People never interact with these protocols directly and use a layer of indirection such as a HTTP/2 client for HTTP, and the same applies for IPv6: use DNS (or your hosts file).

[butlerm]

There are a number of relevant issues here, including the general problem that DNS is not trustable and is not reliable or not reliable enough to use for configuring routers and firewalls. It is not even necessarily accessible or usable for reverse lookup at all. DNS wasn't really designed for common cases where network administrators enter IP address prefixes. That could probably fixed to some degree using a name system that was designed for security use, including operation when the network is partitioned or wildly malfunctioning.

And of course the need to maintain two sets of IP addresses and two sets of IP address prefixes - even and especially in DNS itself - is probably the number one factor slowing down the deployment of IPv6. That and far too many places, far too many interfaces, far too many protocols, and far too many APIs (notably Berkeley sockets) that are not transparent to which network layer protocol is being used or what the address format is. The wire format, transfer format, configuration format, and administration of DNS address records is a case in point.

[supriyo-biswas]

Adding another DNS record or changing a socket listener is hardly the issue though. Most sysadmins are unfamiliar with IPv6 networking concepts such as NDP, DHCPv6 and so on, and having to learn a new system is what hinders its adoption.

Unfortunately, such changes are quite common in networking; Linux networking has many moving parts these days, there was the move to iproute2 and nftables, and the like, so one can only try to best keep up with the changes.

[NoZebra120vClip]

> the same applies for IPv6: use DNS (or your hosts file).

And for reverse DNS, PTR records? What should we use there?

[supriyo-biswas]

If you're setting up your private DNS resolvers, you can add PTR records to it. There's nothing special about PTR records in IPv6, they're just DNS records for "in6-addr.arpa" instead of "in-addr.arpa".

[NoZebra120vClip]

How many PTR records should you add for the customary 64-bit Interface ID that applies to one device configured with SLAAC?

https://datatracker.ietf.org/doc/html/rfc8501#page-4