ASN Prefix Explorer & BGP IP Block Lookup
Look up IPv4 and IPv6 network prefix blocks announced by an Autonomous System Number (ASN) across global BGP routing tables.
About the ASN Prefix Explorer
An Autonomous System Number (ASN) is a globally unique identifier assigned by Regional Internet Registries (RIRs like ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC) to networks operating under a unified BGP routing policy. The iN2 ASN Prefix Explorer queries live global routing databases to enumerate all active IPv4 and IPv6 CIDR prefix blocks originated by an Autonomous System.
Use Cases
- Firewall & Access Control Lists: Generating white-lists or geo-blocking rule sets for network infrastructure.
- ISP Peering & Transit Audits: Verifying IP address space originated by upstream service providers.
- Security Incident Response: Isolating IP ranges belonging to cloud providers, hosting companies, or botnets.
- BGP Route Leak Audits: Checking expected vs. actual advertised prefixes across global BGP tables.
Relevant RFC Standards
BGP routing definitions follow RFC 4271 (A Border Gateway Protocol 4) and RFC 1930 (Guidelines for Creation, Selection, and Registration of an Autonomous System).