Skip to content
TechToolsHQ
NewsReviewsGuidesTech 101Tech SeriesToolsNewsletter
TechToolsHQ

Independent, research-driven tech coverage — breaking news, in-depth reviews, buying guides, and technical tutorials to help you understand and choose with confidence.

Explore
NewsReviewsGuidesTech 101Tech SeriesFree Tools
Legal
About UsOur AuthorsContact UsPrivacy PolicyTerms of ServiceCopyright & DMCAAffiliate DisclosureEditorial PolicyAdvertise With Us

© 2026 TechToolsHQ. All rights reserved.

Tools / Reverse DNS (PTR) lookup

Reverse DNS (PTR) lookup

Verify reverse pointer records (PTR) for mail deliverability, server attribution, and forward-confirmed reverse DNS (FCrDNS) diagnostics.

Loading tool…

About this tool

Reverse DNS resolves an IP address back to a hostname via its PTR record — the opposite of a normal lookup. This tool performs that reverse lookup for any IPv4 or IPv6 address, which is important for mail deliverability, server attribution and forward-confirmed reverse DNS (FCrDNS) checks.

Mail servers frequently reject or distrust senders whose IP has no PTR record or whose PTR does not match the forward record, so confirming reverse DNS is a standard step in diagnosing email problems. It also helps attribute an address to a host when reviewing logs or connections.

Use it to check that a sending server’s reverse DNS is set correctly, to run an FCrDNS verification, or to identify the hostname behind an address. It reflects the current PTR data published for the IP.

Frequently asked questions

What is a PTR record?
A pointer record that maps an IP address to a hostname — the reverse of the usual name-to-address lookup. It is what reverse DNS resolves.
Why does reverse DNS matter for email?
Mail servers often require a sending IP to have a PTR record that matches its forward record. A missing or mismatched PTR is a common cause of rejected or distrusted mail.
What is FCrDNS?
Forward-confirmed reverse DNS: the PTR resolves to a hostname whose forward record points back to the same IP. Passing it is a sign of a properly configured server.
Does it work for IPv6?
Yes. It resolves PTR records for both IPv4 and IPv6 addresses.

Enjoying Reverse DNS (PTR) lookup?

TechToolsHQ is an independent, reader-supported tech platform. If this free tool saved you time, solved a problem, or helped your workflow, consider supporting our work. Your support helps us keep our utilities 100% free, private, and ad-free for everyone.

100% optional · Reader supported · Independent researchSupport our work

Related tools

  • WHOIS domain lookupInspect domain registration, registrar, creation, and expiration dates.
  • Open port checkerTest TCP connectivity and firewall rules across standard application ports.
  • URL redirect tracerTrace 301, 302, and 307 redirect chains and inspect HTTP status codes.
  • XML sitemap validatorCheck XML sitemap health, count indexed URLs, and detect broken links.
  • cURL to code converterConvert cURL commands into JavaScript fetch, Python requests, Node axios, Go, PHP and Rust.
  • Docker run to Docker Compose converterConvert docker run CLI commands into clean, production-ready docker-compose.yml files.

Browse all tools