Look up any Autonomous System by AS number or IP address: owner organization, announced prefixes, registration countries, and hosting/cloud classification.
| First address | Last address | Size |
|---|---|---|
| 8.8.4.0 | 8.8.4.255 | 256 |
| 8.8.8.0 | 8.8.8.255 | 256 |
| 34.0.0.0 | 34.0.63.255 | 16,384 |
| 34.0.96.0 | 34.0.239.255 | 36,864 |
| 34.1.16.0 | 34.1.64.255 | 12,544 |
| 34.1.66.0 | 34.1.81.255 | 4,096 |
Showing 6 of 71 ranges.
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Every network that participates in internet routing — from a national ISP to a single-rack hosting company — is identified by an Autonomous System Number. When you look up an ASN (or the ASN behind an IP address), you learn who actually operates the network a packet comes from, which is far more reliable than reverse DNS or geolocation alone.
This tool answers three practical questions. First, who owns an IP? The ASN's registered organization name identifies the operator even when the IP has no PTR record. Second, how big is the network? The announced range counts show whether you're looking at a small regional operator or a global backbone. Third, is it a datacenter? We flag ASNs operated by cloud, hosting, CDN, and VPN-infrastructure providers — the single strongest signal that traffic is machine-generated rather than a person on a home connection.
The data comes from a local snapshot of the global BGP table (derived from RouteViews collector data, refreshed with each site deployment — currently 2026-07-14), covering 91,065 ASNs and 411,961 IPv4 ranges. Lookups run entirely on our servers against this snapshot; your queries are not forwarded to any third-party API.
Common uses: tracing abusive traffic to its operator before filing an abuse report, building firewall or WAF rules that treat cloud ASNs differently from residential ones, verifying a peering candidate's announced footprint, and checking whether "residential proxy" traffic really originates from consumer ISP space.
An Autonomous System Number (ASN) identifies a network that runs its own routing policy on the internet — an ISP, cloud provider, university, or large enterprise. BGP routers use ASNs to exchange reachability information. There are roughly 100,000 allocated ASNs, ranging from small regional ISPs to networks like AS16509 (Amazon) announcing thousands of prefixes.
Enter the IP address in the search box above. The tool matches it against a local snapshot of the global BGP routing table (derived from RouteViews data) and returns the ASN that announces the covering prefix, along with the organization name.
These are the IP ranges the ASN originates into the global BGP routing table. The counts shown here are contiguous address ranges from the routing snapshot, which is a close approximation of the raw prefix count — adjacent prefixes announced by the same ASN are merged.
We maintain a curated list of 50+ major cloud, hosting, CDN, and VPN-infrastructure ASNs (AWS, Google Cloud, Azure, Hetzner, OVH, DigitalOcean, and others), plus a name-based heuristic for smaller hosts. If an IP's ASN matches, traffic from it originates in a datacenter rather than a residential connection.
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