IPASKBGP
The routing protocol that carries “this prefix is reachable via this path” across the internet.
BGP (Border Gateway Protocol) is how networks tell each other which IP prefixes they can reach and through which path. Every announced prefix has an origin AS and an AS path.
Looking glasses (RIPEstat, bgp.tools, bgp.he.net) let you see the origin AS for an address. That origin is what platforms and blocklists effectively use.
BGP has no built-in security: a network can announce space it does not own. That is what RPKI and DROP-style lists try to catch.
Related: Residential IP · Native IP · Dual ISP · CGNAT · ASN · RPKI · Anycast · CDN edge