BGP Route Lookup

Look up BGP routing information for IP addresses and prefixes

Example Lookups

BGP Lookup

About BGP Routing

What is BGP?

Border Gateway Protocol (BGP) is the routing protocol of the Internet. It's used to exchange routing information between autonomous systems (AS) and determines the best path for data to travel across the global Internet.

AS Path

The AS path shows the sequence of autonomous systems a route has traversed. It is used to prevent routing loops and as a primary path selection criterion.

  • Origin AS: The AS that originally advertised the prefix
  • Path Length: Number of ASes in the path; shorter is preferred
  • AS Prepending: Artificially lengthening path by repeating ASN for traffic engineering

BGP Route Types

  • Announced: Prefix is actively advertised in BGP (Visible in global routing tables)
  • Not Announced: Prefix not currently advertised (May be allocated but not routed)
  • More Specific: Longer prefix (more specific) within a larger block (Overrides less specific routes)
  • Less Specific: Shorter prefix (less specific) covering this range (Backup route if more specific withdrawn)

About RIPE RIS

This tool uses RIPE NCC's Routing Information Service (RIS), which collects and stores Internet routing data from multiple locations worldwide. RIS provides valuable insight into the global routing system.

Quick Tips

  • More specific prefixes (longer subnet masks) take precedence over less specific ones
  • AS paths show the route from observer to origin, not your local path
  • Multiple prefixes for an IP may indicate deaggregation or anycast
  • Compare origin AS with WHOIS data to verify legitimate ownership
  • Route changes can take minutes to propagate globally
  • Private ASNs (64512-65535) should never appear in the global routing table
  • Unusually long AS paths may indicate route leaks or suboptimal routing