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Free PTR record checker and reverse DNS lookup

Many mail servers check that a sending IP address has a PTR record and that the hostname resolves back to the same IP. Enter an IP address to see its PTR hostname and whether forward-confirmed reverse DNS passes.

Enter a public IPv4 or IPv6 address.

Background

What is a PTR record?

A PTR record is a reverse DNS record that maps an IP address to a hostname, the opposite of an A or AAAA record. Receiving mail servers look up the PTR record of the connecting IP address and check that the hostname resolves back to the same address before they trust the sender.

How to read the result

A mail server should have a PTR hostname that resolves back to the same IP address. This is called forward-confirmed reverse DNS. Receivers compare it with the hostname the server uses when it connects.

The organization that controls the IP address, usually your hosting or cloud provider, publishes the PTR record. You cannot change it in your own domain’s DNS.

Coverage

What this tool checks

  • The PTR record for an IPv4 or IPv6 address
  • The hostname returned by reverse DNS, and its TTL
  • The reverse lookup name and reverse DNS zone
  • Whether the hostname resolves back to the same IP address (forward-confirmed reverse DNS)

Troubleshooting

Common problems and how to fix them

No PTR record
Ask the provider that controls the IP address to publish reverse DNS. If you send from a cloud or VPS provider, request the PTR record from the provider’s control panel or support team. You cannot set a PTR record in your own DNS zone.
Generic provider hostname
Hostnames that embed the IP address can look like home connections to receivers. Ask for a PTR on a hostname in your own domain, such as mail.example.com.
Forward DNS mismatch
Update the hostname’s A or AAAA record, or change the PTR record, so both directions point to the same host and address.
Unexpected hostname
Confirm you entered the public sending IP. A relay or network address translation can change the address that receivers actually see.

Example

IP address:    192.0.2.10
PTR hostname:  mail.example.com
Forward check: mail.example.com → 192.0.2.10
The PTR hostname resolves back to the original IP address, so reverse DNS is forward-confirmed.

FAQ

Questions about reverse DNS

Who can change a PTR record?
The organization that controls the IP address. Contact your hosting, cloud, or network provider.
Is a PTR record required to send email?
Many receivers reject or penalize mail from servers without reverse DNS. A PTR hostname that resolves back to the same IP is expected for any server that sends mail directly.
Can one IP address have several PTR records?
DNS allows it, but mail servers should use a single hostname so identity checks give consistent results.
What is forward-confirmed reverse DNS?
It means the IP address resolves to a hostname through its PTR record, and that hostname resolves back to the same IP address through an A or AAAA record.

Keep checking

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Dedicated IP

An IP reserved for your team.

About Dedicated IP
Specifications
RFC 1035: Domain Names: Implementation and Specification (opens in a new tab)
RFC 1912: Common DNS Operational and Configuration Errors (opens in a new tab)