Reverse DNS Lookup

Translate an IPv4 or IPv6 address into its exact reverse-DNS name, query authoritative PTR evidence, and verify whether returned hostnames resolve forward to the original address.

IPv4 and IPv6 normalization
Authoritative PTR and TTL evidence
Forward-confirmed reverse DNS
Delegation and DNSSEC diagnostics

IPv4 or IPv6 address

Enter one bare address. CIDR prefixes, ports, zone IDs, hostnames, and ambiguous IPv4 octets with leading zeroes are rejected.

Discovery resolver

Used for zone discovery and validation controls; PTR evidence is queried directly from authoritative servers.

Normalized query preview

Canonical address: 8.8.8.8
Expanded IPv6
Absolute PTR query name: 8.8.8.8.in-addr.arpa.
Address scope note: No common special-use prefix detected.

Live examples:

One address is checked at a time because each run contacts the reverse zone’s authoritative servers and may perform bounded forward verification. Results depend on live public DNS and the same-origin Octetify DNS analyzer; no private or split-horizon DNS is queried.

Reverse DNS result

Query overview

Canonical input, exact reverse transformation, selected discovery resolver, and service timing.

Address
Family
PTR query
Resolver
Completed
Analyzer time
Evidence
Cache

PTR answers and authoritative evidence

All hostnames observed from authoritative endpoints are retained. TTL is evidence reported by those endpoints, not a countdown for a local resolver cache.

Forward-confirmed reverse DNS (FCrDNS)

Each PTR hostname is resolved in the original address family: A for IPv4 or AAAA for IPv6. A pass requires the exact canonical input address to appear in that hostname’s authoritative forward answers. This is a consistency check, not proof of identity or ownership.

Reverse-zone authority

Authoritative reverse DNS server observations
Nameserver	Public endpoints	Reachability	RCODE / outcome	Latency	TTL

Delegation and DNSSEC

These diagnostics describe the reverse zone that serves the PTR name. “Indeterminate” means the bounded analyzer could not collect enough evidence; it does not mean secure or insecure.

Delegation trace evidence

Delegation trace steps
Hop	Current zone	Server	RCODE	Next delegation / answer	Latency

DNSSEC resolver claims

DNSSEC resolver claim evidence
Resolver	Address	RCODE	AD claim	CD control	Latency

Analyzer findings

Actionable warnings supplied by the analyzer. An empty list means no analyzer warning was emitted, not that every possible DNS issue was excluded.

Portable evidence

The raw view includes the authoritative PTR analysis and every completed forward-confirmation analysis. Downloading JSON preserves the same evidence with a generated timestamp.

View raw JSON

How to read a reverse lookup

NXDOMAIN vs NODATA

NXDOMAIN says the queried reverse name does not exist. NODATA says the name exists but has no PTR RRset. Both mean no PTR hostname was returned, but they are different DNS outcomes.

PTR is a published claim

The address-block operator controls the reverse zone. A PTR name can be missing, generic, stale, or point anywhere; it does not enumerate every website hosted on the address.

FCrDNS adds consistency

A PTR hostname passes FCrDNS only when its forward A or AAAA answers contain the original address. Mail systems commonly use this signal, but it does not replace SPF, DKIM, or DMARC.

Standards basis: RFC 1035 defines PTR records and IN-ADDR.ARPA; RFC 3596 defines nibble-reversed IP6.ARPA names; RFC 2308 distinguishes negative-answer forms.