Reverse DNS Lookup
Find the hostname assigned to an IP address through its PTR record (reverse DNS).
- Runs on our servers
- Free to use
About this tool
Reverse DNS maps an IP address back to a name through PTR records in the in-addr.arpa and ip6.arpa zones. This lookup returns the PTR record of any public IPv4 or IPv6 address and offers a one-click forward check so you can confirm that the hostname resolves back to the same IP, the test most mail systems perform.
Use it to vet addresses found in server logs, to confirm that a mail server is set up correctly before sending, or to see which provider an address belongs to when whois is ambiguous.
This is what a result looks like (trimmed):
$ dig -x 8.8.8.8 +short
dns.google.How to use it — quick steps
- 01
Enter the ip address
Type or paste the ip address in the field above. The lookup runs from our servers, not from your device.
- 02
Press "Lookup PTR record"
Press "Lookup PTR record" or Ctrl + Enter. The result appears below in a few seconds. Results can be copied.
- 03
Read the result
It appears in the dark panel under the form in a few seconds. Every block has [copy] and other actions.
Key features of this tool
External lookups
The lookup runs from our infrastructure, so you see what the public internet sees without exposing your own IP address or network.
Fast and cached
Results come back in seconds; identical lookups are cached for a few minutes to keep the service fast and responsive for everyone.
Easy to reuse
Every result block can be copied with one click or downloaded as a text file, and tables can also be saved as CSV for your reports.
Frequently asked questions
What is reverse DNS used for?
Mail servers check that the sending IP has a PTR record that resolves back to the same address (forward-confirmed reverse DNS); without it messages are often rejected. It also helps identify crawlers, ISPs and hosting providers in logs.
Who sets the PTR record?
The owner of the IP block, normally your ISP or hosting provider. Many hosting panels let you edit it; residential ISPs set generic names you cannot change.
Is a generic PTR like 1-2-3-4.dynamic.isp.net bad?
For a mail server, yes: it signals a residential line. For anything else it is harmless.