Reverse DNS Lookup
Turn an IP address into a hostname with a live PTR lookup. Works for IPv4 and IPv6, straight from your browser.
Reverse DNS (PTR) lookup
Enter an IPv4 or IPv6 address to find the hostname it points back to.
Results will appear here.
How reverse DNS works
A normal lookup turns a name into an address. Reverse DNS does the
opposite: it asks which hostname an IP address claims as its own, stored
in a special PTR record. To do that, the address is rewritten into a
pointer name — IPv4 addresses use the .in-addr.arpa
domain and IPv6 addresses use .ip6.arpa.
This tool builds that pointer for you and queries it live over
DNS-over-HTTPS, so nothing passes through our servers.
How to read the result
If a PTR record exists, you will see the hostname the IP points to — for example a mail server, a CDN edge node or an ISP gateway. An empty result is not an error: PTR records are optional and are set by whoever owns the IP block. For email senders, the rule of thumb is that the PTR should resolve to a name that, looked up again, points back to the same IP (forward-confirmed reverse DNS).
| Result | What it means |
|---|---|
| Hostname found | The IP has a PTR record — common for servers and infrastructure. |
| No PTR record | Normal for many home and cloud IPs; nothing is broken. |
Frequently asked questions
What is reverse DNS?
Reverse DNS (rDNS) maps an IP address back to a hostname using a PTR record. It is the opposite of a normal lookup: instead of name → address, it answers address → name.
Why does an IP have no PTR record?
PTR records are optional and are controlled by whoever owns the IP block — usually your ISP or hosting provider, not the website operator. Many residential and cloud IPs simply have no reverse record, which is normal.
Why does reverse DNS matter for email?
Mail servers often reject or downrank messages from IPs without a valid, matching PTR record. If you run your own mail server, a correct reverse DNS entry that matches your sending hostname improves deliverability.
Does this work for IPv6?
Yes. The tool builds the correct .ip6.arpa pointer for IPv6 addresses and queries it the same way as IPv4. Many IPv6 addresses still have no PTR record, so an empty result is common.
Chasing a network problem?
Reverse DNS is one clue. To see whether an issue is your line, your DNS or the destination, run the full check-up — it measures speed, latency and DNS together and explains the verdict.