ASN Information Lookup

An ASN (Autonomous System Number) is a basic unit of internet routing; every ISP / cloud / large org has one. Enter an AS number (e.g. 13335) or any IP, and this tool resolves its holder, country, registry (RIR), how many IPv4 / IPv6 prefixes it announces, and its upstream / downstream neighbour ASNs — live.

Holder and neighbours are just the surface — what decides whether a block of IPs works is its purity: datacenter ASN or not, heavily flagged as proxy / abuse, on a blacklist. Datacenter / IDC blocks often suffer reputation by association. So after the ASN, check the purity of your exit IP's ASN.

Holder and routing neighbours are just the surface — what decides whether your IP works is its purity: datacenter ASN or not, heavily flagged as proxy / abuse, on a blacklist. Datacenter / IDC blocks often suffer reputation by association.

Check the purity and risk of your exit IP's ASN →

Check your own IP — purity, risk score, native vs datacenter, leaksCheck IP →

FAQ

What is an ASN and how do I find an IP's ASN?

An ASN identifies an independently-managed network. Paste an IP and the tool first resolves its ASN, then looks up the holder and routing info.

How do I tell if an ASN is datacenter or residential / native?

The holder name is often a clue (cloud / IDC usually means datacenter). For a precise verdict use this site's IP check, which combines multiple sources for datacenter / residential, native / broadcast and risk.

What do upstream / downstream ASNs mean?

Upstream (left) provides this network its internet access; downstream (right) are networks it provides access to. More neighbours usually means a higher tier.