ASN Lookup
Enter an IP address or an ASN (e.g. AS15169) to see which network operator it's registered to.
Overview
Every block of IP addresses on the internet is announced by an Autonomous System (AS) — a network operator identified by a numeric ASN. This tool accepts either an IP address (resolving it to the ASN that announces it via the free Team Cymru DNS service) or an ASN directly, then looks up that ASN's registration details — name, handle, and status — from its Regional Internet Registry via RDAP.
This is useful for identifying which organization or hosting provider actually operates a given IP address, beyond what a plain WHOIS lookup on the IP block alone would show.
Examples
Looking up an IP's ASN
8.8.8.8
AS15169 — GOOGLE
How It Works
- Enter an IP address (e.g. 8.8.8.8) or an ASN (e.g. AS15169).
- Complete the verification check if shown.
- Click Look Up.
- Review the ASN, its registered name, and announced network details.
Use Cases
Identifying a hosting provider behind an IP
Find out which network operator an IP address belongs to, e.g. when investigating traffic or abuse reports.
Looking up an ASN's registration details
Enter an ASN directly to see its registered name and status.
Tips
- A single IP block (BGP prefix) can be announced by more than one ASN in rare multi-homed setups — this tool reports the first one returned.
- Enter an ASN as either a bare number (15169) or with the AS prefix (AS15169) — both work.
FAQ
From Team Cymru's free, public DNS-based WHOIS service, which maps IP ranges to their announcing ASN using live BGP routing data.
This lookup queries external internet-registry infrastructure on your behalf, so a quick bot check helps keep the tool available and responsive for everyone.