HOWTO: IPv6 reverse DNS zone names

[coryr]

The IPv6 rDNS public beta service has been announced here. IPv6 reverse zones are different from IPv4 reverse zones.

An IPv4 reverse DNS zone name for 192.168.0.0/24 will be: 0.0.168.192.in-addr.arpa. Doing zones for CIDR netblocks gets much more crufty.

The IPv6 rDNS scheme is more straight forward, though longer. For this netblock:

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2001:470:1f05:c8e::/64

you will also be tracing the network address backward, though we will not use any trailing 0's. Note that all middle 0's must be included. Separate every numeral with a dot to get:

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e.8.c.0.5.0.f.1.0.7.4.0.1.0.0.2

And instead of "in-addr.arpa" (because all IPs are "internet addresses"), we'll designate that it's IPv6 using:

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.ip6.arpa

Keeping this in mind, our IPv6 rDNS zone looks like this:

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e.8.c.0.5.0.f.1.0.7.4.0.1.0.0.2.ip6.arpa

You can add PTR records via the interface we provide. Note you'll need to backfill any double-colon (::) zeroes you use.

Hope this helps!