whatsmydns.net - DNS Propagation Checker
  1. What's My DNS?
  2. DNS Tools
  3. Reverse DNS Generator

Reverse DNS Record Generator

192.168.1.2 in reverse DNS format:

2.1.168.192.in-addr.arpa

Convert IPv4 and IPv6 addresses into reverse DNS record formats for PTR records in DNS zones.

How do you generate reverse DNS PTR records?

By using the Reverse DNS generator tool on this page, you can instantly generate PTR records by converting any valid IPv4 or IPv6 address into its corresponding entry required for a reverse DNS PTR record. You simply need to enter the address and press the convert button.

DNS records used for Reverse DNS lookups, known as PTR records are represented in a different format depending on whether they are for IPv4 or IPv6 addresses. They are stored as a special entry in the DNS zone for the .arpa domain. IPv4 addresses are within .in-addr.arpa while IPv6 addresses are under .ip6.arpa.

IPv4 Reverse DNS Generator

In order to create a PTR record used for reverse DNS for the corresponding IPv4 A record forward lookup, the IP address will need to be converted in a specific way and placed in the .in-addr.arpa zone.

Rules for generating IPv4 reverse DNS records

The following set of rules uses the example IPv4 address: 127.0.0.1

  1. Split the IP address into parts separated by each dot (.) - 127.0.0.1 becomes 127, 0, 0, 1
  2. Reverse the order of each part - 1, 0, 0, 127
  3. Join each part back together with a dot (.) - 1.0.0.127
  4. Add .in-addr.arpa to the end of the address - 1.0.0.127.in-addr.arpa

IPv6 Reverse DNS Generator

In order to create a PTR record used for reverse DNS for the corresponding IPv6 AAAA record forward lookup, the IP address will need to be converted in a specific way and placed in the .ip6.arpa zone.

This address must be generated from the fully expanded IPv6 address to ensure consistency.

Rules for generating IPv6 reverse DNS records

The following set of rules uses the example IPv6 address: 2002:7f00:1::

  1. Expand the IPv6 address - 2002:7f00:1:: becomes 2002:7f00:0001:0000:0000:0000:0000:0000
  2. Remove all the colons (:) - 2002:7f00:0001:0000:0000:0000:0000:0000 becomes 20027f00000100000000000000000000
  3. Reverse the entire result - 00000000000000000000100000f72002
  4. Add a dot (.) between each character - 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.0.0.f.7.2.0.0.2
  5. Add .ip6.arpa to the end of the address - 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.0.0.f.7.2.0.0.2.ip6.arpa

Example Reverse DNS Records

Any valid IP address can be converted into their corresponding reverse DNS entry, below are a few examples:

IP Address Reverse DNS Record Description
127.0.0.1 1.0.0.127.in-addr.arpa IPv4 Reverse DNS record
192.168.1.2 2.1.168.192.in-addr.arpa IPv4 Reverse DNS record
2002:7f00:1:: 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.0.0.f.7.2.0.0.2.ip6.arpa Compressed format IPv6 Reverse DNS record
2002:7f00:0001:0000:0000:0000:0000:0000 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.0.0.f.7.2.0.0.2.ip6.arpa Expanded format IPv6 Reverse DNS record

Other IP Address Tools