DNS Toolkit — Reverse DNS, Record Lookup & Propagation Checker — IT Ops Tools

What the DNS Toolkit covers

Reverse PTR lookups with ASN enrichment and eight forward record types resolved client-side over DNS-over-HTTPS, plus a server-side global propagation check.

Reverse (PTR) Lookups

Resolves an IP address back to its hostname via the PTR record, then enriches it with ASN, network range, and registry (RIR) details — useful for identifying who actually owns an address you see in logs.

Eight Forward Record Types

Looks up A, AAAA, CNAME, MX, NS, TXT, SOA and CAA records in parallel for any domain, with toggles to include or exclude specific record types from the query.

IPv4 & IPv6 Support

Reverse lookups work against both IPv4 addresses and IPv6 addresses (including compressed notation), so the same tool covers dual-stack environments.

ASN & Network Enrichment

Surfaces the autonomous system number, announcing network, and organisation behind an IP — handy for quickly distinguishing cloud/hosting traffic from residential or corporate ranges.

CAA Policy Checks

Reads CAA records to show which certificate authorities are authorised to issue TLS certificates for a domain — a quick way to verify certificate issuance policy is configured as expected.

Resolved via DNS-over-HTTPS in Your Browser

Reverse and forward lookups run client-side over encrypted DNS-over-HTTPS straight from your browser — nothing you query is logged or stored on our servers.

Global Propagation Map

The Propagation tab queries a rotating sample of resolvers worldwide over UDP port 53 and plots each answer on a live map — green agrees with the majority, amber still differs, grey didn't answer — so you can watch a change roll out.

Anycast vs. Geographic Resolvers

Distinguishes anycast resolvers (Google, Cloudflare, Quad9, OpenDNS) — whose answer reflects the node nearest our server — from resolvers pinned to a country, which give a true regional signal for spotting GeoDNS/CDN differences and stale TTLs.

Frequently asked questions

What is a reverse DNS (PTR) lookup?

A reverse DNS lookup takes an IP address and returns the hostname assigned to it through its PTR record in the in-addr.arpa (IPv4) or ip6.arpa (IPv6) zone — the opposite of a forward lookup that turns a name into an IP.

Why does an IP address have no PTR record?

PTR records are optional and are published by whoever controls the IP address reverse zone, usually the network operator. Many addresses — especially dynamic, cloud, or residential ones — have no PTR configured, so the lookup returns nothing.

What is the difference between forward and reverse DNS?

Forward DNS resolves a domain name to records such as A, AAAA, MX or TXT. Reverse DNS does the opposite, resolving an IP address back to a hostname. The two are configured independently and do not have to match.

What is an ASN?

An Autonomous System Number identifies the network that announces an IP address on the internet via BGP. It tells you which organisation — an ISP, cloud provider, or enterprise — is responsible for routing that address.

What is DNS propagation?

DNS propagation is the time it takes for a DNS change to be visible everywhere. Resolvers around the world cache records until their TTL expires, so after an update some locations return the new value while others still serve the old one.

How long does DNS propagation take?

Usually anywhere from a few minutes to 48 hours. The main factor is the record TTL: a resolver keeps serving its cached answer until the TTL counts down, so records with lower TTLs propagate faster.

Why do some locations still show the old DNS record?

Those resolvers cached the previous answer and will not refetch until the TTL expires. Anycast resolvers and ISPs that stretch short TTLs can also lag, which is why a change can look complete in one region but not another.

How do I check if my DNS has propagated globally?

Open the Propagation tab, enter your domain, pick the record type (A, AAAA, CNAME, MX, NS, TXT or SOA) and run the check. The toolkit queries resolvers worldwide and shows, on a live map, how many agree with the majority answer.

Is the DNS Toolkit free?

Yes. It is free and needs no sign-up. Reverse and forward lookups run client-side over encrypted DNS-over-HTTPS from your browser; the propagation check runs server-side, querying resolvers directly over UDP port 53 with no third-party propagation API in the middle. Nothing you query is stored.