ASN lookup
Look up an autonomous system by number or find the ASN behind any IP address: the operator, its registry and country, and every IPv4 and IPv6 prefix it announces, from the live BGP routing table and the registries.
Amazon.com, Inc.
Announced prefixes
Showing 20 of 15,993 announced prefixes (samples from the iptoasn.com BGP table and RIPEstat); the full list is on the per-ASN pages once they launch.
| Prefix | Type | Source |
|---|---|---|
| 1.44.96.0/24 | IPv4 | iptoasn.com |
| 1.118.3.0/24 | IPv4 | iptoasn.com |
| 1.178.1.0/24 | IPv4 | iptoasn.com |
| 1.178.7.0/24 | IPv4 | iptoasn.com |
| 1.178.8.0/21 | IPv4 | iptoasn.com |
| 1.178.17.0/24 | IPv4 | iptoasn.com |
| 1.178.18.0/23 | IPv4 | iptoasn.com |
| 1.178.20.0/22 | IPv4 | iptoasn.com |
| 1.178.24.0/22 | IPv4 | iptoasn.com |
| 1.178.28.0/23 | IPv4 | iptoasn.com |
| 1.178.31.0/24 | IPv4 | iptoasn.com |
| 1.178.64.0/23 | IPv4 | iptoasn.com |
| 1.178.81.0/24 | IPv4 | iptoasn.com |
| 1.178.86.0/23 | IPv4 | iptoasn.com |
| 1.178.88.0/21 | IPv4 | iptoasn.com |
| 1.178.100.0/22 | IPv4 | iptoasn.com |
| 1.178.104.0/21 | IPv4 | iptoasn.com |
| 1.178.144.0/20 | IPv4 | iptoasn.com |
| 1.178.160.0/21 | IPv4 | iptoasn.com |
| 1.178.168.0/24 | IPv4 | iptoasn.com |
Sources used for this result
- iptoasn.com (BGP table) offline-db · ok · Oct 22, 2026
- Team Cymru ASN record (DNS) live-dns · ok · 11 ms
- RIPEstat Data API live-api · ok · 4500 ms
Look up an ASN or IP
Enter an ASN (AS15169 or 15169) or an IP address. For an address we first find the announcing ASN (iptoasn.com, Team Cymru and RIPEstat cross-checked), then load the ASN's record.
ASN details
The record combines registry and routing data.
Owner and country
The organization that registered the ASN and the country of registration, from the regional registry via RDAP and RIPEstat. A network can operate in many countries under one ASN.
Registry
Which of the five regional registries (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC) issued the number, and when.
Prefixes
The number of announced IPv4 and IPv6 prefixes and the total address space, with the list below. An ASN with no announced prefixes exists on paper only.
Peers and upstreams
The networks this AS exchanges routes with, from public BGP collectors (RIPE RIS via RIPEstat). Upstreams are the providers it buys transit from; peers exchange traffic as equals.
Announced IPv4 and IPv6 prefixes
Every prefix the AS currently announces, as seen by the route collectors, with the first-seen date where available. Click a prefix to look up its registry record; the per-ASN pages (for example /as/15169) keep this list bookmarkable.
What is an ASN?
An autonomous system is a set of networks under one routing policy — an ISP, a cloud provider, a large company, a university. Each gets a number from its registry and uses it in BGP, the protocol routers use to announce which prefixes they can deliver traffic to. There are about 75,000 active ASNs; the number is the most reliable identifier of who is responsible for an address, because it comes from the routing table rather than from a database. Your own ASN is on the what is my ISP page.
Frequently asked questions
How do I look up an ASN?
Enter the number above (with or without the AS prefix) to see the operator, registry data and announced prefixes. From a terminal, whois -h whois.cymru.com AS15169 or dig +short AS15169.asn.cymru.com TXT give a one-line summary.
How to check IP ASN?
Enter the address above, or check the IP address lookup and what is my ISP pages, which show the ASN of any address and of your own connection.
What is ASN in IP address lookup?
The number of the autonomous system that announces the address's prefix in BGP — effectively the network operator responsible for routing it. It identifies the operator more reliably than names, which change with mergers and brands.
Is ASN the same as ISP?
Usually the same organization, but not the same thing: an ISP is a company; an ASN is a routing identifier it uses. Large ISPs have several ASNs; some small ISPs have none and use their upstream's.
Who assigns ASNs?
The regional internet registries (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC), from blocks delegated by IANA. Registries check that the applicant needs one — typically a network with its own routing policy and more than one upstream.
How do you get your own ASN number?
Become a member (or a sponsored end user) of your regional registry, show that you will connect to at least two other networks with your own routing policy, and pay the registry's fee. Most hobbyist and small networks get one through a sponsoring member.
ASN data: iptoasn.com (BGP table, daily), Team Cymru IP-to-ASN (live DNS), RIPEstat Data API (RIS routing data, live) via the CheckMyIP lookup service.