Reverse DNS Lookup

Look up the hostname associated with an IPv4 address using a PTR record lookup. Enter an IP address to see what hostname it resolves back to.

IPv4 Address

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Why use Reverse DNS Lookup?

Reverse DNS lookup finds the hostname associated with an IP address by querying a PTR record at a special reverse-notation domain (e.g. 8.8.8.8 is queried as 8.8.8.8.in-addr.arpa). This tool builds that query automatically from a plain IP address input, using the same DNS infrastructure as the site's DNS Lookup tool.

Key benefits

Automatically builds the correct in-addr.arpa query
Uses the same DNS infrastructure as the DNS Lookup tool
No signup required

Features

IPv4 to hostname (PTR record) lookup
Automatic reverse-notation domain construction

Popular use cases

Identifying the hostname behind a server IP in a log file
Verifying reverse DNS is configured for a mail server (often required to avoid spam filtering)
Investigating an unfamiliar IP address

How to use Reverse DNS Lookup

1
Enter an IPv4 address
Type the IP address you want to look up, e.g. 8.8.8.8.
2
Lookup
Click Lookup to query the PTR record for that IP.

Frequently asked questions

What is a PTR record?

A PTR (pointer) record maps an IP address back to a hostname — the reverse of a normal A record, which maps a hostname to an IP address.

Why does my lookup return no results?

Not every IP address has a PTR record configured — reverse DNS is opt-in and set up by whoever controls the IP block, so many IPs (especially residential or dynamic ones) have none.

Does this support IPv6?

This version supports IPv4 addresses only.

Last reviewed: July 2026

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