Question 1

What is an Autonomous System Number (ASN)?

Accepted Answer

An Autonomous System (AS) is a collection of connected IP routing prefixes under the control of one or more network operators that presents a common, clearly defined routing policy to the Internet.

Question 2

What is Border Gateway Protocol (BGP)?

Accepted Answer

BGP is the core routing protocol of the global Internet. It exchanges reachability information between Autonomous Systems (ASNs) to determine optimal paths across network nodes.

Question 3

What are Internet Exchange Points (IXPs)?

Accepted Answer

IXPs are physical facilities allowing ISPs and content delivery networks (CDNs) to exchange Internet traffic directly between their networks, reducing cost and latency.

Question 4

How can I find all IP prefixes announced by an ISP?

Accepted Answer

Searching an organization's ASN in our tool (e.g. AS15169 for Google) returns the full list of IPv4 and IPv6 prefixes advertised to the global BGP routing table.

ASN Lookup