Can I look up both IPv4 and IPv6 addresses?

Yes, the tool supports querying both IPv4 and IPv6 addresses and ASNs, returning routing and registration data for each.

Do I need to create an account to use the lookup?

No account is required; the service is publicly available for basic use without mandatory paid plans.

What kind of information will I get back from a query?

You will receive BGP origin ASN, prefix data, and additional routing metadata flags showing ownership and registry details for the specified identifier.

How accurate are the routing metadata flags returned?

The flags reflect data from public registries like ARIN and are suitable for network diagnostics, though they may be delayed or incomplete for recently allocated resources.

NetworkTool Review

BGP AS Lookup

Provided byTeam Cymru IP to ASN Lookupcymru.com

This free lookup tool maps IP addresses to BGP origin ASN/prefix data and also accepts ASN queries. It supports IPv4 ...

One of 5 options for BGP AS Lookup

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Screenshot of BGP AS Lookup on Team Cymru IP to ASN Lookup — cymru.comOpen the live tool →

About this tool

What BGP AS Lookup does

The Free BGP AS Lookup tool at Team Cymru resolves Border Gateway Protocol Autonomous System Number and IP address registration records using ARIN's RDAP web search interface. Users can query either an IP address or an ASN to retrieve structured ownership and registry information. The service supports both IPv4 and IPv6 inputs and exposes additional routing metadata flags, making it a versatile option for network diagnostics. As a publicly available tool with no mandatory paid plan for basic use, it provides direct access to routing data without subscription barriers.

Step by step

How to use the Team Cymru IP to ASN Lookup BGP AS Lookup

1
Enter an IP address or ASN number into the search field on the Team Cymru lookup page
2
Select whether the query targets an IP address or an Autonomous System Number
3
View the returned results showing BGP origin ASN, prefix data, and routing metadata flags
4
Use the structured ownership and registry information for network troubleshooting or research

Is it right for you

Best for

Network administrators, developers, and researchers who need quick, free access to BGP routing and registration data for IPv4 or IPv6 addresses and ASNs.

Limitations

Results depend on public registry availability and may be delayed
Interface is functional but lacks advanced filtering or visualization options
No unit switching or format customization beyond the standard RDAP output

Questions

BGP AS Lookup FAQ

Can I look up both IPv4 and IPv6 addresses?: Yes, the tool supports querying both IPv4 and IPv6 addresses and ASNs, returning routing and registration data for each.
Do I need to create an account to use the lookup?: No account is required; the service is publicly available for basic use without mandatory paid plans.
What kind of information will I get back from a query?: You will receive BGP origin ASN, prefix data, and additional routing metadata flags showing ownership and registry details for the specified identifier.
How accurate are the routing metadata flags returned?: The flags reflect data from public registries like ARIN and are suitable for network diagnostics, though they may be delayed or incomplete for recently allocated resources.

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