BYTETOOLS

PTR Record Generator

Build reverse-DNS PTR records for IPv4 and IPv6: in-addr.arpa and ip6.arpa names plus the ready-to-paste zone-file line. Pure formatting, no lookups.

Zone-file PTR record (IPv4)

10.2.0.192.in-addr.arpa. 3600 IN PTR mail.example.com.

Reverse-DNS name

10.2.0.192.in-addr.arpa

Parent zone (/24 delegation)

2.0.192.in-addr.arpa

PTR records live in the zone your provider delegates to you — add the record there. This tool only formats the record; it does not perform a reverse lookup.

What is the PTR Record Generator?

The PTR Record Generator builds the reverse-DNS name for any IP address — reversed octets under in-addr.

  • IPv4 reverse names — reversed octets + .in-addr.arpa
  • IPv6 reverse names — all 32 nibbles reversed + .ip6.arpa, generated correctly
  • Complete zone-file line with TTL, class and trailing dots
  • Shows the parent delegation zone (/24 for IPv4, /64 for IPv6)
  • Validates the address and the target hostname before generating
  • 100% offline — formats records, never queries DNS

How to use the PTR Record Generator

  1. 1

    Enter the IPv4 or IPv6 address — the type is detected automatically.

  2. 2

    Enter the hostname the address should resolve back to, e.g. mail.example.com.

  3. 3

    Set the TTL in seconds (3600 is a sensible default).

  4. 4

    Copy the zone-file PTR line, or just the reverse name, and add it to your reverse zone.

About the PTR Record Generator

The PTR Record Generator builds the reverse-DNS name for any IP address — reversed octets under in-addr.arpa for IPv4, reversed nibbles under ip6.arpa for IPv6 — and emits the complete zone-file PTR line with your hostname, TTL and correct trailing dots.

Reverse DNS matters most for mail servers: many receivers reject or distrust mail from IPs whose PTR record is missing or does not match the HELO name. Writing the IPv6 nibble format by hand — 32 reversed hex digits — is exactly the kind of error-prone chore this tool removes.

It is a pure formatter: it never performs a reverse lookup or contacts any DNS server. Everything is string manipulation done 100% locally in your browser, so it works offline and nothing you type is transmitted.

Frequently asked questions

What is a PTR record?

A PTR record is the reverse of an A or AAAA record: it maps an IP address back to a hostname. It lives under the special in-addr.arpa (IPv4) or ip6.arpa (IPv6) domains, with the address components reversed so that DNS delegation follows network ownership.

Why do mail servers need PTR records?

Most large mail receivers check that the sending IP has a PTR record and that it forms a sensible forward-confirmed pair with an A/AAAA record. Missing or generic reverse DNS is a strong spam signal, and some servers reject such mail outright, so a correct PTR is essential for deliverability.

How is an IPv6 PTR record formatted?

The address is expanded to all 32 hex digits, each digit becomes one DNS label, the order is reversed, and .ip6.arpa is appended. For example 2001:db8::567:89ab becomes b.a.9.8.7.6.5.0.0.0…0.8.b.d.0.1.0.0.2.ip6.arpa. This tool generates that string for you, which is far safer than typing it.

Where do I add the PTR record — my domain's DNS?

Usually not. Reverse zones follow IP ownership, so the PTR normally goes in your hosting provider's or ISP's control panel, or in a reverse zone they delegate to you. Many clouds set it from an API or support ticket. This tool gives you the exact record to request or paste.

Does this tool check my existing reverse DNS?

No — it builds and formats records only and performs no lookups at all. To verify a live PTR you would query DNS with a tool like dig -x from a machine with network access. Keeping this generator offline is what makes it safe for internal addressing too.

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