What Is My Reverse DNS
Your reverse DNS
Detecting…
Reverse DNS (PTR) maps your public IP back to a hostname. Many home and mobile IPs have no PTR record.
How to use
- Open the page — your public IP is detected first, then a PTR lookup runs automatically.
- The hostname appears at the top if a PTR record exists; otherwise the page explains that none was found.
- Click Copy to save the reverse DNS name for email setup, server config, or a support ticket.
FAQ
What is my reverse DNS?
Reverse DNS is the hostname associated with your public IP via a PTR (pointer) DNS record. If one exists, it appears at the top of this page — for example host-203-0-113-42.example.net. Many home and mobile IPs have no PTR record at all.
What is a PTR record?
A PTR record maps an IP address back to a domain name — the opposite of a normal A record that maps a name to an IP. Mail servers and network diagnostics often check PTR to verify the sender's identity.
Why is no PTR record found?
Most residential and mobile IPs do not have reverse DNS configured. ISPs typically assign PTR only to business, dedicated, or server IPs. A missing PTR is normal for home broadband — it is not an error.
Who controls my reverse DNS?
The organization that owns the IP block — usually your ISP or hosting provider — controls PTR records in their DNS servers. You cannot set PTR yourself unless the provider gives you a control panel or API for it.
Does reverse DNS affect email delivery?
Some mail servers reject or flag mail from IPs without a matching PTR or with a generic PTR (for example a cable-modem pool name). This matters for self-hosted mail servers, not typical web browsing.
How is this different from DNS Lookup?
This page detects your own public IP and looks up its PTR record automatically. DNS Lookup is for querying any domain or record type you enter — A, AAAA, MX, TXT, and more.
Introduction
What Is My Reverse DNS detects your public IP and performs a PTR lookup to find the hostname mapped to it, displayed front and center with a one-click copy button. Below it, a details panel lists all PTR records returned and notes when none exist — a common and normal result for home and mobile connections.
Reverse DNS is the mirror of forward DNS: instead of asking "what IP does this name point to?", it asks "what name points back to this IP?". Email administrators, network engineers, and abuse desks check PTR records regularly. Finding yours should not require command-line dig -x — this page runs the lookup from your live address.
What is reverse DNS?
Reverse DNS (rDNS) uses PTR records in the in-addr.arpa (IPv4) or ip6.arpa (IPv6) zones to map an IP address to a hostname. Forward and reverse should ideally agree:
| Direction | Record type | Example |
|---|---|---|
| Forward (name → IP) | A record | mail.example.com → 203.0.113.42 |
| Reverse (IP → name) | PTR record | 203.0.113.42 → mail.example.com |
A typical residential PTR might look like a generic pool name:
c-203-0-113-42.hsd1.ca.comcast.net
A business or server PTR is often a meaningful hostname:
mail.example.com
Why PTR records matter
- Email deliverability — many SMTP servers verify that the connecting IP's PTR matches or relates to the sending domain.
- Network diagnostics —
tracerouteand log analysis often show PTR names instead of bare IPs. - Abuse and security — incident responders use PTR to identify the responsible network operator quickly.
Home users rarely need a custom PTR, but knowing whether one exists — and what it says — helps when setting up a home mail server or debugging delivery issues.
Common use cases
- Self-hosted email — verify your ISP assigned a PTR and that it matches your mail hostname.
- Server provisioning — confirm a hosting provider set reverse DNS after you requested it.
- Support tickets — paste your PTR when a provider asks for reverse DNS details.
- Curiosity check — see whether your residential IP has any hostname at all (often it does not).
Best practices
- No PTR is normal on residential and mobile IPs — do not treat it as a misconfiguration.
- If you need a custom PTR for mail, request it from your ISP or host — it cannot be set from your router.
- Forward and reverse DNS should match for mail servers — if you run
mail.example.com, ask your provider to set PTR to that name. - For forward DNS queries on any domain, use DNS lookup; for your public IP and ISP, see what is my IP.