What Is an ASN — A Plain-English Guide for Proxy Users

If you work with proxies and keep hearing "AS24940," "Hetzner ASN," "Datacenter ASN" without quite knowing what those numbers refer to — this article clears it up. In plain English: ASN is a network's "passport" on the internet, and it determines how websites perceive you.

What ASN means in simple terms

ASN (Autonomous System Number) is a unique number assigned to an "autonomous system" on the internet. An autonomous system is a network of IP addresses owned by one organization and routed under unified policy.

Loosely: the internet is a patchwork of tens of thousands of ASes. Each AS has its own number. Hetzner — AS24940. Google — AS15169. Cloudflare — AS13335. AWS — AS16509. Comcast — AS7922. And so on.

When you rent a VPS at Hetzner, your IP gets "citizenship" in AS24940. When a site receives a request from that IP, it can look up the ASN and instantly know it's a Hetzner data center.

How ASNs are organized

ASNs are issued by Regional Internet Registries (RIRs): RIPE for Europe, ARIN for US/Canada, APNIC for Asia, LACNIC for Latin America, AFRINIC for Africa. Getting your own ASN isn't cheap or trivial — you need justification (your own routing equipment, BGP setup, networks no smaller than /24).

Originally ASNs were 16-bit (up to 65,535); now they're 32-bit (up to ~4 billion). Roughly 110,000 ASNs are issued globally today.

Why ASN matters when choosing proxies

Antifraud systems (Cloudflare, IPQS, MaxMind, fingerprintjs, etc.) maintain a database of every known ASN with tags: "datacenter," "residential ISP," "mobile carrier," "VPN provider," "known proxy network," and so on.

When a site looks up your IP, it instantly knows the ASN, and via the database — who's behind it. If the IP is in AS24940 (Hetzner) — that's Datacenter, immediately suspicious to most consumer-facing sites. If the IP is in AS6128 (Cablevision/Optimum) — that's Residential, a normal home subscriber.

So two proxies in the same country (e.g. both US) can behave radically differently against antifraud. One in a datacenter ASN gets banned in a minute. The other in a residential ASN passes freely.

How IP type is derived from ASN

ProxyLab and most analytical services use lookup tables of "ASN → network type":

Datacenter ASNs: Hetzner (AS24940), OVH (AS16276), DigitalOcean (AS14061), AWS (AS16509), Linode (AS63949), Google Cloud (AS15169) and hundreds more.
Residential ASNs: home ISPs — Comcast, Verizon FIOS, BT, Deutsche Telekom, etc. Thousands worldwide.
Mobile ASNs: cellular carriers — T-Mobile, Vodafone, MTS, Megafon, Orange, NTT Docomo. Fewer in number, often dedicated to mobile networks separately.
Hosting/VPN ASNs: dedicated to VPN services (Mullvad, ProtonVPN, NordVPN, Private Internet Access).

Antifraud engines also keep "reputation" scores per ASN: what % of traffic from this AS is fraudulent, scammy, spammy. That reputation feeds the "trust" decision when allowing or blocking a request.

How to look up an ASN

Several ways:

ProxyLab "Check My IP" — shows ASN and network type.
bgp.he.net — detailed BGP info for any IP/ASN.
ipinfo.io — simple lookup.
Via whois on the command line:
```
whois -h whois.cymru.com " -v 1.2.3.4"
```

Common ASNs: data centers vs ISPs

A short cheat sheet:

AS24940 — Hetzner Online (DE) — Datacenter
AS16276 — OVH (FR) — Datacenter
AS14061 — DigitalOcean (US) — Datacenter
AS16509 — Amazon AWS — Datacenter
AS15169 — Google — Datacenter
AS13335 — Cloudflare — CDN/Datacenter
AS7922 — Comcast (US) — Residential
AS5089 — Virgin Media (UK) — Residential
AS21928 — T-Mobile (US) — Mobile
AS25180 — Vodafone (UK) — Mobile

If your proxy lives in a "datacenter" ASN — for strict antifraud sites (banks, marketplaces, ad accounts) it's basically useless. If it's in residential or mobile — your odds are much better.