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CGNAT (Carrier-Grade NAT)

CGNAT is a technique carriers use to share one public IP among many customers — which is exactly why mobile proxy IPs are so trusted and hard to block.

Last updated May 28, 2026

Definition

Carrier-Grade NAT (CGNAT) is a large-scale form of Network Address Translation that lets an ISP or mobile carrier share a single public IPv4 address among hundreds or thousands of subscribers. It exists largely because IPv4 addresses are scarce.

Why CGNAT matters for proxies

Because many real users sit behind the same CGNAT public IP, blocking that IP would punish many legitimate customers. This is the core reason mobile proxies carry such high trust — banning a mobile IP is risky for a website. CGNAT also means the visible IP can change frequently as the carrier reassigns addresses.

Examples

1

Hundreds of mobile subscribers sharing one carrier public IP

2

A mobile proxy's IP rotating naturally as the carrier reassigns it

Common Use Cases

Understanding why mobile proxies resist bans
Explaining shared IP reputation
IPv4 address conservation by ISPs

Frequently Asked Questions

Many real users share each carrier IP, so blocking one would affect many legitimate customers — sites avoid doing it.
It can. Carriers reassign shared public IPs over time, so the externally visible address may change without any action on your part.

Keep Learning

All terms

Residential Proxy

A residential proxy routes your traffic through a real home internet connection, so websites see an ordinary ISP customer rather than a server in a data centre.

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IP Rotation

IP rotation is the practice of automatically cycling through multiple IP addresses so that successive requests originate from different IPs.

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Mobile Proxy

A mobile proxy routes traffic through a real 4G or 5G cellular connection. Because carriers share one IP among thousands of phone users, these are the hardest proxies for websites to block.

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