Reverse IP Lookup

Turn an IP address back into a name

A normal DNS lookup turns a name into an IP address. A reverse lookup goes the other way: you give it an IP address and it asks DNS for the host name registered for that address, using what's called a PTR record. The result often reveals who runs the server, for example a host name like mail.example.com or server123.hostingcompany.net.

Reverse lookups help system administrators, email senders and security analysts understand where traffic is coming from. A visitor IP in your logs that resolves to a search engine's crawler domain, a cloud provider or a residential ISP tells you a lot about what you're looking at.

Not every IP has a PTR record. If nothing is returned, the network owner simply hasn't set one up.

How to use the reverse ip lookup

1. Enter the IPv4 or IPv6 address.
2. Submit the lookup.
3. Read the host name returned, if one exists.
4. For more context, run the host name through a DNS or Whois lookup.

Common uses

• Identifying the network or company behind an IP address in your server logs.
• Checking that your mail server's IP has a PTR record that matches its host name, which many receiving servers expect.
• Verifying that a crawler claiming to be a search engine really comes from that search engine's domain.
• Investigating abusive traffic or brute-force login attempts.
• Documenting servers and IP ranges in your own infrastructure.

Tips and things to know

• For email, the PTR record should point to a host name whose A record points back to the same IP (called forward-confirmed reverse DNS). Mismatches increase the chance of mail landing in spam.
• PTR records are set by whoever controls the IP block, usually your hosting or cloud provider, not in your domain's DNS zone.
• Shared hosting servers host many sites on one IP, but the PTR record only names the server itself.
• To estimate the location of the IP, use the IP lookup. To check a domain's records, use the DNS lookup.

Frequently asked questions

What is a PTR record?

A pointer record maps an IP address to a host name. It's the basis of reverse DNS.

Why does my IP have no reverse DNS?

The provider that owns the IP hasn't configured a PTR record. Ask your host or cloud provider to set one.

Does reverse DNS matter for email deliverability?

Yes. Many mail servers check that the sending IP has a valid PTR record and treat missing or generic ones as a spam signal.

Can I find all websites hosted on an IP?

A PTR lookup only returns the name configured for the IP, usually the server's host name, not every site hosted on it.

Related tools

• IP Lookup: Get approximate IP details.
• DNS Lookup: Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
• Website hosting checker: Get the web-host of a given website.
• Whois Lookup: Get all possible details about a domain name.
• HTTP headers lookup: Get all the HTTP headers that an URL returns for a typical GET request.