ASN and BGP Prefix Lookup by IP
Enter an IPv4 or IPv6 address to see its origin ASN, advertised BGP prefix and autonomous system name.
How to read the result
Compare the origin ASN and prefix with information from your provider or autonomous system. An unexpected ASN is a reason to investigate, but it does not by itself prove a route leak or hijack.
Before making a network decision, also check RPKI, IRR records and your upstream operator. Public routing sources may update with a delay.
Frequently asked questions
What is an origin ASN?
The ASN of the autonomous system that originates the BGP prefix containing the queried IP.
Where does the data come from?
The tool obtains reference data about public BGP routing through Team Cymru WHOIS.
Is IPv6 supported?
Yes, the lookup works for both IPv4 and IPv6 addresses.
Does an unexpected ASN prove a route hijack?
No. It is a signal for further investigation. Compare the result with RPKI, IRR and information from your network operator.
