What is a reverse DNS ARPA pointer?

An in-addr.arpa pointer reverses the IPv4 octets (e.g. 8.8.8.8 ➔ 8.8.8.8.in-addr.arpa) used by DNS servers to perform reverse IP-to-hostname lookups.

Updated: August 2026 • Verified v1.2

IP Geolocation & Network ASN Inspector

Internet & NetworkNetwork

Local Browser Execution: Your input is processed locally in your browser and is not sent to UTL servers.

Deterministic IP Scope Classification: Octet Parsing ➔ CIDR Matching ➔ ARPA Generation

Was this calculation helpful?

Understanding Your Results

Classifies IP addresses into public or private RFC scopes, generates reverse DNS PTR records, renders 32-bit binary octet streams, and optionally queries public city/country/ISP data.

Practical Guidance & Next Steps

RFC 1918 subnets (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) are private non-routable ranges and do not have public geolocation.

What is this?

A networking utility that classifies IP address ranges, scopes, and network routing metadata.

How does it work?

1. Enter an IPv4 or IPv6 address. 2. View deterministic client-side analysis (scope, RFC 1918 status, reverse ARPA, binary breakdown). 3. Optionally click 'Query Public Geolocation' to look up city, country, and ISP.

Why use it?

Quickly determines whether an IP address in firewall logs is internal, carrier-grade NAT, or external.

Technical Scope & Calculation Limitations

Client-side scope analyzer executes locally. External geolocation requires an active internet connection to query public WHOIS.

Frequently Asked Questions

RFC 1918 defines private IP ranges (10.x.x.x, 172.16.x.x–172.31.x.x, 192.168.x.x) reserved for internal local networks that cannot be routed directly over the public internet.

Windows Desktop & Widget Options