Quick Answers

What Is an ASN?

An ASN, or autonomous system number, identifies the network that owns a block of IP addresses. Websites use it to tell home internet providers from datacenters.

By Team of Monkeys Editorial Updated 1 min read Affiliate disclosure

This guide contains affiliate links to Geonode, Webshare and Rayobyte. If you buy through them we may earn a commission, at no extra cost to you.

What Is an ASN illustration: an ASN, or autonomous system number, identifies the network that owns a block of IP addresses 3jdej38j4

The short answer

An ASN (autonomous system number) is a unique number given to a network that runs its own routing on the internet, such as an ISP, a mobile carrier, a university or a cloud company. Every public IP address belongs to some ASN.

Why it matters for proxies

Looking up an IP's ASN tells a website who owns it. If the ASN belongs to a hosting company, the visitor is probably a server. If it belongs to a consumer ISP or a mobile carrier, it is probably a person. Anti-bot systems block whole ASNs at once, which is why buying proxies spread across several ASNs is safer than buying many IPs from one.

ISP proxies are interesting here: they sit in datacenters but use address blocks registered to consumer ISPs, so their ASN looks residential.

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Also known as

Autonomous system, AS number, network operator ID.

Learn more

Affiliate disclosure: Team of Monkeys is an affiliate of Geonode, Webshare and Rayobyte. Links and banners marked as sponsored, and links to Geonode, Webshare and Rayobyte in the text, use our referral links, and we may earn a commission if you buy through them, at no extra cost to you. Our explanations and comparisons are written to be useful whichever provider you choose.

Editorial note: Proxy providers change their pools, features and prices often, so treat any figures here as typical ranges at the time of writing and confirm current terms with the provider before you buy.
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