IP Address Lookup - Network Intelligence & Geolocation

An IP address lookup reveals detailed information about any IP — geographic location, hosting provider, reverse DNS records, and network relationships. Use robtex.com to discover the infrastructure behind any IPv4 or IPv6 address.

What IP Lookup Reveals

Every IP address carries metadata that tells a story about its origin and purpose. Our lookup tool extracts:

  • Geographic location - Country, city, and coordinates based on regional internet registry data
  • Network ownership - The organization or ISP that controls the address block
  • ASN details - Autonomous System information showing the network's position in global routing
  • PTR records - Reverse DNS hostnames configured for the IP
  • A record for - All domains currently resolving to this IP, with nested lookups showing each domain's other IPs
  • Previously A record for - Domains that used to resolve to this IP but no longer do, revealing past hosting relationships
  • Related infrastructure - Other IPs on the same network, shared hosting relationships

How to Use IP Lookup

Enter any IP address in the search box. For IPv4, use dotted decimal notation like192.0.2.1. For IPv6, use standard colon-separated format like2001:db8::1.

Results display immediately, showing the address's network context and all associated DNS records. Click any related hostname or ASN to explore connected infrastructure.

Common Use Cases

Security investigation - Trace suspicious traffic back to its source network. Identify whether an IP belongs to a known hosting provider, residential ISP, or cloud platform.

Network troubleshooting - Verify that DNS records resolve correctly and that reverse DNS is properly configured for mail servers and other services requiring PTR records.

Competitive research - Discover what hosting infrastructure competitors use and identify shared hosting relationships.

Abuse reporting - Find the correct abuse contact for a network by identifying the responsible ASN and organization.

Understanding Results

Results are organized into distinct sections:

  • PTR — Reverse DNS pointer records configured by the IP owner (e.g., mail servers needing valid PTR for deliverability)
  • A record for — Domains currently resolving to this IP via passive DNS observation. Each domain shows nested A records so you can see what other IPs it also uses, revealing shared hosting and CDN patterns
  • Previously A record for — Historic relationships: domains that once resolved to this IP but have since moved. Useful for tracking infrastructure migrations, identifying former tenants, and security investigations
  • IP numbers used in conjunction — Other IPs frequently co-hosted with domains on this address

A single IP might host hundreds of domains. Our passive DNS database captures these relationships over time, exposing shared hosting patterns and infrastructure changes invisible in simple WHOIS lookups.

→ Look up an IP address on robtex.com

For IP reputation and blocklist checking, see RBLS.org which checks IPs against 100+ DNSBLs.

FAQ

What's the difference between IPv4 and IPv6 lookup?
Both work identically. IPv6 addresses contain more routing information but return the same categories of data: location, ownership, and DNS records.
How current is the geolocation data?
IP geolocation is updated regularly from regional internet registries. Accuracy varies - datacenter IPs are highly accurate while mobile and residential IPs may show approximate locations.
Can I look up my own IP?
Yes. Enter your public IP to see how your network appears to external services and verify your reverse DNS configuration.
Why do some IPs show no reverse DNS?
Not all IP addresses have PTR records configured. This is common for residential connections and some cloud providers.
What does "Previously A record for" show?
Domains that used to resolve to this IP but no longer do. This passive DNS history reveals past hosting relationships — useful for security investigations, tracking infrastructure migrations, and understanding which sites previously shared an IP.
How far back does the historic data go?
Our passive DNS observations go back to 2009, with coverage varying by domain, depending on when we first observed the domain-to-IP relationship.