Reverse DNS Zones

Last updated October 26, 2026

Note

Reverse DNS zones are available on the Solo Pro plan and higher. See the differences between plans.

A reverse DNS zone holds the PTR records that map IP addresses back to hostnames. DNSimple can host reverse zones for IPv4 and IPv6 addresses, as long as whoever controls your IP addresses delegates the reverse zone to DNSimple.

How reverse zones are named

Reverse zones live under two special domains: in-addr.arpa for IPv4 and ip6.arpa for IPv6. The IP address is written backwards, so the most specific part comes first, like the labels of any other domain name.

IPv4: For the address 192.0.2.4, the reverse zone for the 192.0.2.0/24 network is 2.0.192.in-addr.arpa. Inside that zone, the PTR record for the address has the name 4.
IPv6: Each hexadecimal digit of the address becomes one label, in reverse order. For the address 2001:db8::567:89ab, the reverse zone for the 2001:db8::/64 network is 0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa. Inside that zone, the PTR record for the address has the name b.a.9.8.7.6.5.0.0.0.0.0.0.0.0.0.

When you add a reverse zone in DNSimple, you can type the zone name, or enter the network with its prefix length (such as 2001:db8::/64), select Parse an IP address?, and let DNSimple work out the zone name for you.

For the full record format, see the PTR Record Reference.

Why delegation matters

Adding a reverse zone to your DNSimple account does not make it answer queries on its own. Resolvers find a reverse zone the same way they find any other zone, by following delegation from the parent. For IP addresses, the parent is controlled by whoever allocated the addresses: a Regional Internet Registry (RIR), or the internet service provider, hosting company, or cloud provider you got the addresses from.

Before you set up a reverse zone, make sure you can have the reverse zone for your address range delegated to DNSimple’s name servers. Depending on your provider, you may not have control over this. In that case, ask your provider to set up the PTR records you need on their own name servers instead.

Have more questions?

If you have additional questions or need any assistance with reverse DNS zones, just contact support, and we will be happy to help.