BGP Prefix Lookup
Find the routed prefix and origin ASN for an IP.
Use the BGP Prefix Lookup tool
What this bgp prefix lookup does
BGP Prefix Lookup asks RIPEstat for the routed prefix that covers an IP address or CIDR block, then shows the origin ASN, the network holder, the containing registry block and any related less-specific prefixes.
The answer describes routing metadata, not reachability. RIS collectors see most of the global table but can miss very small or filtered announcements, and different networks can choose different paths. A prefix appearing here does not prove that a host answers ping, HTTP or any other service.
Why use it
- Identify which network originates an address before reporting abuse.
- Check that a prefix is actually announced after a BGP change.
- Separate a registry allocation from the more specific route in use.
- Add origin ASN context to a firewall or incident note.
How to use it
- 1Enter an IPv4 or IPv6 address, or a CIDR prefix such as 8.8.8.0/24.
- 2Run the lookup and wait for RIPEstat to answer.
- 3Read the routed prefix, origin ASN and holder.
- 4Compare the related prefixes with your own routing looking glass before changing filters.
Worked examples
Address inside a routed prefix
Input
8.8.8.8
Output
The covering /24, origin AS15169, the holder and the containing /8 registry block.
IPv6 prefix
Input
2001:4860:4860::/48
Output
The announced IPv6 prefix and its origin ASN, or a clear message when no route is visible.
Common mistakes
- Entering a hostname or AS number; this tool accepts addresses and prefixes only.
- Reading “announced” as “reachable”; BGP visibility and service availability are different.
- Confusing the containing RIR block with the route that is actually announced.
- Assuming every network sees the same path; route selection is local.
Frequently asked questions
Where does the routing data come from?
RIPEstat's prefix-overview API, which aggregates observations from the RIS route collectors.
Can I look up an AS number?
Not in this tool. It reports the route covering an address or prefix. Use the separate ASN Lookup tool to map an IP to its origin ASN.
Why is the reported prefix different from what I entered?
RIPEstat aligns an address or more-specific block to the covering announced prefix. The table shows both the query and the routed prefix.
Does it show the full BGP path?
No. It reports the origin ASN and prefix, not every AS on every path. A looking glass or RIS raw data shows paths.