Reverse IP Lookup in your browser, no signup

Find the hostname published for an IP address. A reverse lookup asks DNS for the PTR record, which is the name the owner of the address block has attached to it - and it is the record mail servers, firewalls and abuse desks check when deciding whether to trust traffic. Leave the field blank to look up the address you are connecting from. Not every address has a PTR record, and that is normal for home connections; for a mail server it is a problem worth fixing.

SEO and webmaster checks are only useful if they match what Googlebot or a browser would see. Guessing from the HTML source alone is how people ship broken tags.

Reverse IP Lookup is a good fit when checking that a mail server has matching forward and reverse DNS before chasing deliverability.

In plain English

Reverse IP Lookup is built around a few practical wins, not a long feature list:

• Shows the actual PTR record with its TTL rather than a cached guess.
• One click looks up the address you are connecting from, with nothing to type.
• Explains what a missing record means instead of showing an empty result.
• Copy button for pasting a hostname straight into a ticket or config.
• Works for both IPv4 and IPv6 addresses.
• Free, instant and no signup.

How to run it

1. Enter an IP address. Type any public IPv4 or IPv6 address, or leave it blank to look up your own.
2. Run the lookup. The PTR record is queried live from DNS and shown with its TTL.
3. Check it matches. For a mail server, the hostname should also resolve forward to the same address.

Real situations

• Checking that a mail server has matching forward and reverse DNS before chasing deliverability.
• Identifying who owns an address that appears in your server logs.
• Confirming that a hosting provider set up reverse DNS after you requested it.
• Investigating an unfamiliar IP in a firewall or abuse report.
• Finding the hostname behind an address flagged by a monitoring alert.
• Verifying that a crawler claiming to be a search engine really resolves to one.

Small habits that help

• For mail servers, the PTR should match the hostname used in the SMTP greeting.
• A missing PTR on a home or mobile connection is completely normal.
• Reverse DNS is set by whoever owns the address block, so ask your host to change it.
• Confirm the forward record too - a PTR that does not resolve back is treated as suspicious.
• TTL tells you how long a change will take to propagate.

Skip these

• Expecting every IP to have a hostname - most do not, and that is not an error.
• Assuming the PTR proves ownership; anyone controlling the block can publish any name.
• Trusting a crawler because its PTR says Google without checking the forward record too.
• Trying to look up a private address such as 192.168.x.x, which has no public reverse DNS.
• Changing reverse DNS at your registrar - it is set by the address block owner, not the domain registrar.

Does anything leave your device?

Reverse IP Lookup needs the ToolBox API for work a browser cannot do. What you submit is processed, then discarded. It is not kept as a library of your files.

Related tools worth opening next

If this is one step in a longer job, these usually come after it:

• Ping Tool - Measure latency, jitter and packet loss to any server - from our network, not yours
• SMTP Tester - Check that a mail server answers, negotiates TLS, and accepts your login - step by step
• Website Speed Test - Real browser-rendered GTmetrix-style report: grade, Core Web Vitals, page weight and fix recommendations

Open the Reverse IP Lookup when you are ready. It is free, and you do not need an account.