Most proxies are flagged before they send a single byte. The site judged the IP — its type, its ASN, its neighbors — and decided. Here's how that judgment works in 2026, and how to land on the right side of it.
IP reputation is what a website decides about your IP before it looks at your request — built from IP type, ASN score, abuse history, and subnet cleanliness. Datacenter ASNs score low and get blocked on sight; real 4G/5G mobile carrier ASNs score high because CGNAT means hundreds of real users share each address. In 2026 the IP layer matters more than rotation speed — pair a trusted IP with a matching fingerprint and you pass.
When a connection arrives, an anti-bot system looks up the IP in milliseconds: what type is it, which ASN announces it, has this address (or its neighbors) misbehaved, and what do third-party fraud feeds say? That lookup produces a reputation verdict that gates everything after it. A clean browser fingerprint on a burned datacenter IP still loses — the IP already failed.
This is why "works on my laptop, blocked on the server" is so common: your laptop sits on a residential or mobile ASN with good reputation, while your server sits on a datacenter ASN that detectors block by default. The code is identical; the IP's reputation is not.
Datacenter, residential, or mobile — and the specific network announcing it. The single biggest factor. How ASN scoring works →
Your IP is judged by its neighbors. A clean /24 beats a fast-rotating dirty one — cleanliness now outranks rotation frequency. Why subnet > rotation →
Blocklists (DNSBLs), fraud-score vendors (IPQualityScore, ipinfo) and the site's own logs. Once an IP is on a list it's presumed guilty. Check an IP →
Mobile carrier IPs are shared by hundreds of real subscribers, so blocking one punishes real customers. Detectors stay cautious — the structural reason mobile keeps high reputation. Success-rate data →
| IP type | Typical ASN reputation | Why |
|---|---|---|
| Datacenter | Low | Known hosting ASNs; no real users to protect; blocked by default |
| Residential | Medium-high | Real ISP IPs, but some pools are overused or consent-questionable |
| Mobile (4G/5G) | Highest | Carrier ASN + CGNAT sharing makes blocking expensive for the site |
Reputation is a spectrum, not a guarantee — a specific mobile IP can still be burned, and a specific residential subnet can be clean. The point is the structural baseline each type starts from.
IP reputation is a trust judgment a website makes about your IP address before it looks at anything you do. It is assembled from the IP type and ASN (datacenter, residential, or mobile carrier), its history of abuse, whether the surrounding subnet is clean, and third-party fraud-score feeds. A low-reputation IP gets challenged or blocked on the first request, no matter how good your headers or fingerprint are.
Every IP belongs to an Autonomous System (ASN) — the network that announces it. Anti-bot systems score ASNs by how much automated abuse comes from them. Hosting/datacenter ASNs (AWS, OVH, DigitalOcean and similar) carry low scores and are blocked aggressively; mobile carrier ASNs carry high trust because real subscribers share them via CGNAT. Your proxy inherits the score of its ASN before you act.
Use the IP type the target trusts. Real 4G/5G mobile IPs sit on carrier ASNs behind CGNAT, so blocking one would block hundreds of real users — which is why they keep high reputation even under heavy use. Residential IPs are next. Datacenter IPs are the easiest to flag. Pair a trusted IP with a matching browser fingerprint so every layer agrees.
Real 4G/5G mobile + residential IPs across 17+ countries — $4/GB, free endpoints, free rotation. The IP layer detectors have the least reason to flag.