Reverse IP Lookup

Find the PTR (reverse DNS) hostname associated with an IP address or domain.

Enter an IPv4 or IPv6 address, or a domain name to resolve first.

What is a reverse IP lookup?

A reverse IP lookup finds the hostname attached to an IP address through reverse DNS. A normal DNS lookup turns a name into an address; a reverse lookup goes the other way, asking which name is recorded for an address. That name lives in a PTR (pointer) record. This tool accepts an IPv4 address, an IPv6 address or a domain name, and shows the PTR hostname if one exists.

Note that this tool finds the reverse DNS name for one address. It does not list every website hosted on a shared server.

How reverse DNS works

PTR records are stored in special DNS zones. For IPv4, the address is reversed and placed under in-addr.arpa, so 8.8.8.8 becomes 8.8.8.8.in-addr.arpa; IPv6 uses ip6.arpa. Those zones are controlled by whoever holds the address block, usually a hosting company or internet provider. That is why the reverse name is set by the network owner, not by the owner of a website using the address.

When you enter a domain, the tool first resolves it to an IP address, preferring IPv4, and then runs the reverse lookup on that address.

How to use the reverse IP lookup

  1. Enter an IP address such as 8.8.8.8, or a domain such as example.com.
  2. Press Reverse Lookup.
  3. Read the IP address, its version and type, and the PTR hostname.
  4. Read the interpretation note below the result for what it means.

What the reverse lookup results mean

PTR found

The address has a reverse name. Names often show the provider and the server's role, for example a mail server name or a generic name based on the address.

No PTR record found

No reverse name is set. This is common for home connections and shared hosting, and is not a fault in itself.

Not applicable

Private, loopback and other special addresses are not used on the public internet, so they have no public reverse name to look up.

Reverse DNS and email delivery

Receiving mail servers often check the PTR record of the server sending to them. Many expect a sending server to have a reverse name, and some also check that the name resolves back to the same address, a match known as forward-confirmed reverse DNS. Missing or generic reverse names can push mail into spam folders. If you run your own mail server, ask your hosting provider to set a PTR record that matches the server's hostname.

Reverse lookups from the command line

You can run the same check in a terminal. On Windows, nslookup 8.8.8.8 returns the PTR name for an address. On macOS and Linux, dig -x 8.8.8.8 does the same, and adding +short prints only the hostname. This tool gives the same answer in a browser, with a short explanation of what it means.

Common uses

  • Checking a mail server's reverse DNS before sending email.
  • Identifying the provider behind an unfamiliar address in a server log.
  • Confirming a PTR change made by your hosting provider.

Common problems and fixes

Your server has no PTR record. PTR records cannot be set at your normal DNS provider. Ask the company that supplies the IP address, usually through its control panel or support team.

The domain could not be resolved. Check the spelling, and confirm the domain has an A or AAAA record with the DNS Lookup.

Related tools

  • IP Lookup combines reverse DNS with network and reputation data.
  • DNS Lookup runs forward lookups for A and AAAA records.
  • MX Lookup finds a domain's mail servers to check.
  • SMTP Test connects to a mail server to test it.

Frequently asked questions

What is a PTR record?

A PTR, or pointer, record maps an IP address back to a hostname. It is the reverse of an A or AAAA record, which maps a name to an address. PTR records are stored in special reverse DNS zones that are controlled by whoever holds the IP address block, usually the hosting provider or internet provider.

Does this tool show all websites on the same IP?

No. It finds the reverse DNS name recorded for one address. Listing every domain hosted on a shared server would need a large database built by crawling the web, which this tool does not use. The PTR name usually belongs to the server or provider, not to any one website.

Why does my IP address have no reverse DNS?

The network that controls the address has not set a PTR record. This is common for home broadband and shared hosting. For a website it rarely matters, but a mail server should have one. Ask the company that provides the IP address to add it.

How do I set up a PTR record?

Contact the provider that gives you the IP address, such as your hosting or cloud company. Many have a reverse DNS setting in their control panel. You cannot add PTR records at your domain's DNS provider, because reverse zones belong to the owner of the address block.

Can I do a reverse lookup on a domain name?

Yes. When you enter a domain, the tool first resolves it to an IP address, using IPv4 if available and IPv6 otherwise, then finds the PTR hostname for that address. The result may be a hosting provider's server name rather than the domain you entered.

Why does the PTR name not match my domain?

Reverse DNS is set by the owner of the address block, so hosting providers often use their own generic names. That is normal for websites. For a dedicated mail server, ask the provider to set the PTR record to your mail server's hostname, which should also resolve back to the same address.

Is reverse DNS important for email?

Yes. Many receiving mail servers check that the sending server's IP address has a PTR record, and some check that the name resolves back to the same address. Missing or generic reverse names can cause messages to be rejected or marked as spam, so mail servers should always have a matching PTR record.