PTR Record Generator (IPv4 & IPv6)
Hand-writing the reverse-DNS name for an IPv6 address means expanding it to 32 nibbles and reversing them under ip6.arpa — easy to get wrong. Paste any IPv4 or IPv6 address and this generator gives you the exact reverse name, a ready-to-paste PTR record, and the reverse zone your provider delegates (a /24 for IPv4, a /64 for IPv6). Optionally pass the hostname the PTR should point to.
Reviewed by the SysGlass team · Updated July 21, 2026
What it checks
- The fully-expanded form of the address (all 8 IPv6 groups, no ::)
- The exact reverse-DNS name: in-addr.arpa for IPv4, ip6.arpa for IPv6
- A ready-to-paste PTR record line for your zone file
- The delegated reverse zone (/24 for IPv4, /64 for IPv6) to ask your host for
- Works identically for IPv4 and IPv6
How to read the result
- The 'Reverse DNS name' is where the PTR record lives — copy it exactly.
- The 'PTR record' row is a complete zone line; replace the hostname with your server's real FQDN.
- The 'Reverse zone' is what your hosting provider/ISP delegates to you; ask them for it if you manage your own reverse DNS.
- For mail servers, make sure the PTR hostname's forward A/AAAA points back to this IP (forward-confirmed reverse DNS).
Frequently asked questions
How do I write the reverse DNS name for an IPv6 address?
Expand the address to its full 32 hex digits, reverse the order of every nibble, separate each with a dot, and append .ip6.arpa. This tool does it for you so you don't make a mistake.
What's the difference between this and a reverse DNS lookup?
A reverse DNS (PTR) lookup queries what PTR an IP currently resolves to. This generator builds the reverse name and PTR record you need to publish — useful when you're creating reverse DNS, not checking it.
What is the reverse zone for /24 and /64?
Providers usually delegate reverse DNS by block: a /24 IPv4 block maps to a three-octet in-addr.arpa zone, and a /64 IPv6 block maps to a 16-nibble ip6.arpa zone. The tool shows the zone for your address.
Who actually publishes the PTR record?
The owner of the IP block — your hosting provider or ISP — controls reverse DNS. Generate the record here, then either add it in their control panel or ask them to delegate the reverse zone to you.