CGNAT is why thousands of real people share a single IP address on mobile networks — and why that makes mobile proxies uniquely powerful and nearly impossible to block.
If you've ever checked your IP address on your phone and then looked it up online, you may have noticed something strange: your carrier's IP resolves to a city that isn't yours, or geolocation tools show wildly inconsistent results. Sometimes, thousands of people appear to be using the same IP.
This isn't a bug. It's CGNAT — and understanding it explains why mobile IPs are the most valuable (and hardest to block) addresses on the internet.
CGNAT stands for Carrier-Grade Network Address Translation. It's a technique mobile carriers (and some ISPs) use to stretch a limited pool of IPv4 addresses across millions of subscribers.
Here's the core problem: there are only ~4.3 billion IPv4 addresses, and they ran out. The internet assigned the last blocks to regional registries in Since then, every carrier has had to get creative.
CGNAT is their solution.
Without CGNAT, NAT works like this:
With CGNAT, there's an extra layer:
Your device gets a private RFC 6598 address (100.64.0.0/10 range — a special block reserved just for CGNAT). The carrier's CGNAT infrastructure then translates thousands of these private addresses to a much smaller pool of public IPs.
| Layer | IP type | Example range | |---|---|---| | Your device | Private (RFC 6598) | 100.64.0.1 – 100.127.255.254 | | Carrier CGNAT pool | Shared public IPv4 | Varies by carrier | | Internet sees | That shared public IP | e.g. 174.209.x.x |
On major carriers like Verizon, AT&T, and T-Mobile, a single public IP can be shared by hundreds to thousands of concurrent users at any moment. The carrier continuously rotates which subscribers map to which public IP.
This rotation happens: When you switch between cell towers When your connection is idle and re-established On a timed schedule (every few minutes to hours, depending on carrier) When you toggle airplane mode on/off
This is the key insight that makes mobile IPs so special.
When a website or platform sees a suspicious request from a datacenter IP (AWS, GCP, DigitalOcean), blocking that IP is easy — it only affects bots, not real users.
But when that same IP is shared by 2,000 real Verizon customers doing legitimate browsing, shopping, and social media, blocking it means blocking all of them. No business can afford that. Instagram can't block Verizon's entire CGNAT pool. Google can't penalize T-Mobile's shared IPs. The collateral damage would be catastrophic.
This is why mobile IPs are treated fundamentally differently by every major platform's trust and safety system.
| | Home broadband | Mobile (CGNAT) | Datacenter | |---|---|---|---| | NAT layers | 1 (home router) | 2 (device + carrier) | 0 (direct public IP) | | Users per IP | 1 household | Hundreds–thousands | 1 server/service | | IP rotation | Static or rare | Frequent | None | | ISP/ASN type | Residential ISP | Mobile carrier | Cloud/hosting ASN | | Detection difficulty | Medium | Very hard | Very easy | | Block risk | Low | Extremely low | High |
Datacenter IPs are immediately identifiable because their ASN (Autonomous System Number) belongs to a hosting provider — not a consumer ISP. Any anti-bot system checks the ASN first. If it's Amazon Web Services or DigitalOcean, it's flagged automatically.
Mobile carrier ASNs (Verizon, AT&T, Vodafone, etc.) are associated with millions of legitimate users. They're never bulk-blocked.
Most modern mobile carriers have deployed IPv6 natively, which solves the address exhaustion problem — IPv6 has 340 undecillion addresses, enough for every device to have a unique one. So why does CGNAT still matter?
Not all websites support IPv6 — the majority of the internet still runs IPvDevices must fall back to CGNAT IPv4 for IPv4-only destinations. Dual-stack is common — most mobile devices have both an IPv6 address and a CGNAT IPv4 address simultaneously. Detection tools still use IPv4 — most IP reputation databases, geolocation services, and anti-bot systems are primarily IPv4-based.
The practical result: even in 2026, mobile traffic regularly goes through CGNAT for IPv4 destinations, and the "shared IP" behavior is as relevant as ever.
A mobile proxy is a real 4G/5G device on a carrier network. When you route your traffic through it:
The exit IP is the carrier's CGNAT public IP That IP is simultaneously used by hundreds of real phone users It has a legitimate carrier ASN It gets naturally rotated by the carrier on a regular schedule No IP reputation database flags it
From the target website's perspective, your traffic looks identical to a real person browsing on their phone.