What Is CG-NAT? Why Mobile Proxy IPs Are So Hard to Block

If you've looked into mobile proxies, you've probably seen the claim that mobile IPs are "impossible to blacklist". The reason is a piece of network technology called CG-NAT. Here's what it is and why it matters.

The IPv4 shortage

Every device on the internet needs an IP address. The original system, IPv4, only has around 4.3 billion addresses — far fewer than the number of phones, laptops and connected devices in the world. Addresses ran out years ago.

Mobile carriers feel this most. A network like O2, EE, Verizon or Vodafone has millions of phones online at once, and nowhere near enough public IPv4 addresses to give each one its own.

What CG-NAT does

CG-NAT stands for Carrier-Grade Network Address Translation. Instead of giving each phone a public IP, the carrier gives it a private address inside its own network. When the phone connects to a website, the carrier's equipment translates that private address into one of a smaller pool of public IPs.

The result: many real subscribers share the same public IP address at the same time. A website sees one IP, but behind it are lots of ordinary people browsing, streaming and using apps.

Why this makes mobile IPs hard to block

Websites block IPs that behave badly. With a datacenter IP, that's easy — nobody legitimate is behind it. With a mobile IP, blocking it would also lock out every genuine customer sharing that address.

So platforms like Instagram, TikTok, Google and major retailers are very reluctant to block mobile IPs. They rely on other signals instead, and they give mobile carrier traffic a high trust score by default.

This is why mobile proxies are the go-to choice for social media management, scraping protected sites and SEO research.

Fresh IPs on demand

There's a second benefit. When a mobile modem reconnects to the network, the carrier assigns it a new public IP from its pool. That's how IP rotation works on a mobile proxy: reconnect the modem and you get a new, clean mobile IP in seconds — no need to buy more addresses.

With ProProxies you can rotate on a timer (from every 5 minutes), on demand from the dashboard, or by calling a rotation link from your own software.

What about IPv6?

Mobile networks increasingly hand out IPv6 addresses too, and there are plenty of those to go around. Our proxies are dual stack: you get the carrier's shared IPv4 address and native mobile IPv6, so IPv6-enabled websites also see a genuine mobile user.

The bottom line

CG-NAT means one mobile IP represents many real people. That makes mobile IPs extremely costly for websites to block, and that's what gives dedicated 4G proxies their trust advantage over datacenter and residential proxies.