The mobile proxy's "unblockable" reputation is not a marketing claim but the result of a network architecture. The name of that architecture is CGNAT — Carrier-Grade Network Address Translation. Once it is understood, which proxy type to choose for which job becomes far clearer.
From NAT to CGNAT
The router in your home already does NAT: the private addresses of the phone, computer and TV inside the house are translated into a single public IP. CGNAT is the same idea carried to carrier scale — except that here the parties sharing are not the devices of the same house, but thousands of subscribers who know nothing about each other.
On mobile networks the second and third layers are nested. The address your phone receives is usually already a private address (the 100.64.0.0/10 range).
How Does Port Sharing Work?
A single IPv4 address has 65,535 ports. CGNAT distributes these ports to subscribers in blocks. If, for example, 1,000 ports are allocated to each subscriber, a single public IP can serve roughly 64 subscribers. With more aggressive allocation, that number rises into the thousands.
By keeping this table, the carrier routes the incoming response to the correct subscriber. When the table fills up, new connections are refused — this is one of the reasons for the occasional "cannot connect" situations on mobile connections.
Why Do Platforms Not Block Mobile IPs?
When a platform blocks an IP address, it ends up blocking everyone using that IP. On a datacenter IP this cost is close to zero — there are no real users behind it. On a mobile IP, thousands of real subscribers are affected.
Instead of blocking mobile IPs, platforms turn to behavioral analysis. This means behavioral discipline remains just as important when you use a mobile proxy.
A mobile proxy protects you from IP-based blocking, but not from behavior-based detection. Excessively fast actions, suspicious session patterns and an inconsistent device fingerprint are detected on a mobile IP as well.
The Side Effects of CGNAT
While this architecture gives the mobile proxy its power, it also brings some limits:
- Incoming connections cannot be accepted: A device behind CGNAT cannot be reached from outside; port forwarding is not possible.
- Port exhaustion: If a large number of simultaneous connections are opened from the same IP, the table can fill up.
- Geographic ambiguity: Because the carrier pool is spread over a wide region, city-level accuracy is low.
- Neighbor effect: If another subscriber sharing the same IP triggers a rate limit, you may be affected too.
- Session restrictions: Some services may link a large number of accounts coming from the same IP.
Most of these problems are inherent to the architecture; they cannot be removed entirely by configuration, only their impact can be reduced.
IPv6 and CGNAT
As carriers move to IPv6, the need for CGNAT decreases, because every subscriber can be given plenty of addresses. But for the mobile proxy this is not an advantage — it is a potential disadvantage: if address sharing decreases, the cost of IP blocking falls as well.
For now, the majority of mobile networks continue to use CGNAT over IPv4, and most target sites still see IPv4 connections. For the differences on the IPv6 side, see our IPv4–IPv6 comparison .
Is There CGNAT on Your Own Connection?
If the IP your device receives while you are on mobile data differs from the IP seen from outside, you are behind CGNAT:
To see your exit IP quickly, you can also use our My IP Address page.
Summary
CGNAT is the carriers' answer to IPv4 scarcity and the one-sentence explanation of the mobile proxy's power: one IP, thousands of real subscribers. That density makes the decision to block economically difficult for platforms. In return, you accept low concurrency, weak geographic precision and the neighbor effect. A mobile proxy is strong against IP-based blocking, but not against behavioral analysis. For product details, see our mobile proxy page .