Reverse IP Lookup

Reverse IP Lookup: Find the Hostname for an IP Address

Enter a public IPv4 address and the tool looks up its reverse DNS (PTR) record. You get back the hostname the address owner published, such as dns.google for 8.8.8.8, or "Hostname not found" if there is none.

How reverse DNS works

Forward DNS maps a name to an address. Reverse DNS goes the other way through a special zone, in-addr.arpa. To look up 203.0.113.25, the tool reverses the octets and asks for the PTR record at 25.113.0.203.in-addr.arpa. The same query from a terminal:

dig -x 8.8.8.8 +short
dns.google.

The holder of the IP block controls that zone, not the domain owner. That is usually your hosting company, cloud provider or ISP. To set a PTR record for your server, use your provider's control panel (AWS, DigitalOcean and Hetzner all have one) or open a support ticket.

Where PTR records matter

• Mail servers: Gmail, Outlook and most other receivers check that a sending IP has a PTR record, and that the name resolves back to the same IP (forward-confirmed reverse DNS). A missing or generic PTR such as ip-203-0-113-25.example-isp.net is a common reason for rejected or spam-foldered mail.
• Logs: a PTR name tells you whose network an address belongs to, for example crawl-66-249-66-1.googlebot.com for a Google crawler.
• Traceroute output: router PTR names often hint at the city or carrier of each hop.

What this tool doesn't do

A PTR record names one host. It doesn't list the websites hosted on an IP. One shared-hosting server can serve thousands of domains, and DNS has no index of them. Services that claim to show "all domains on this IP" build that list from their own web crawls and passive DNS data, so their results are partial and often out of date.

Anyone can also publish any PTR name for addresses they control, so treat it as a hint. Confirm it by resolving the name forward with the DNS Lookup tool, and look up the block owner with IP Whois.