What is an ASN and why do proxy providers mention it
An Autonomous System Number (ASN) identifies the network that owns and routes a block of IP addresses. Every public IP belongs to exactly one ASN, and the mapping is public.
Why it matters for proxies
The fastest way for a site to classify traffic is to look up the ASN behind the IP:
- An ASN registered to Comcast, BT or Deutsche Telekom → a residential connection
- An ASN registered to AWS, DigitalOcean or OVH → a server
That single lookup separates a home user from a datacenter, and it is why cheap datacenter proxies get blocked in bulk on defended targets. The individual address does not need a bad reputation; its ASN gives it away.
What this means in practice
- Residential and ISP proxies carry consumer ISP ASNs, which is the whole point of them.
- Some sites let you filter by ASN when you need traffic from one specific carrier.
- Rotating between addresses inside the same datacenter ASN does not defeat ASN-based blocking. You have to change the class of address, not just the address.
Related: What is a subnet and What is a Data Center.