CGNAT Explained — Why Mobile Proxies Have the Best IP Reputation

When people compare proxy types, they usually talk about speed, price, and geo coverage. What they rarely explain well is why mobile proxies consistently outperform datacenter and residential proxies on every serious platform.

The answer comes down to one technical concept: CGNAT — Carrier Grade NAT.

Understanding CGNAT is the single most useful thing a proxy buyer can learn. It explains why mobile IPs have the best reputation, why they're the hardest to block without collateral damage, and why platforms like Facebook, Google, and Amazon treat them differently at the infrastructure level.

What Is NAT?

To understand CGNAT, start with regular NAT (Network Address Translation).

In a typical home network:

• Your router has one public IP address assigned by your ISP
• All your devices (phone, laptop, TV) share this one public IP
• When you make a request, your router translates your private 192.168.x.x address into the public IP before sending it to the internet

This is NAT at home level — one public IP shared by a small household.

The internet sees one IP address. In reality, there might be 3-8 devices behind it.

What Is CGNAT?

CGNAT (Carrier Grade NAT, also called Large Scale NAT or CGN) is the same concept applied at the carrier level — but at a much larger scale.

Instead of one household sharing one IP, with CGNAT:

• Your mobile carrier (Kyivstar, Orange, LMT) has a pool of public IP addresses
• Thousands of real subscribers share each public IP address
• The carrier's NAT infrastructure translates all these private connections to the shared public IPs
• From the internet's perspective, it looks like all those subscribers are using the same IP

This is not a proxy trick. This is the actual architecture of how mobile internet works globally.

Why Do Mobile Carriers Use CGNAT?

IPv4 addresses ran out. There are only about 4.3 billion possible IPv4 addresses, and the internet has more devices than that.

The original solution was IPv6 — a much larger address space. But IPv6 adoption has been slow, and a huge portion of the internet still runs on IPv4. In the meantime, carriers needed a way to connect billions of mobile devices to an IPv4 internet with far fewer addresses than devices.

CGNAT is the solution:

1. Each subscriber gets a private IP (10.x.x.x or 100.64.x.x — the CGNAT range defined in RFC 6598)
2. The carrier maintains large NAT tables mapping subscriber sessions to public IPs
3. Multiple subscribers share each public IP, differentiated only by port mappings

A single mobile carrier IP can represent anywhere from a few hundred to tens of thousands of real users simultaneously.

The IP Reputation Consequence

Here is where proxy buyers need to pay attention.

When a website or platform evaluates whether to trust an IP address, it looks at:

1. Historical behavior — has this IP been used for spam, fraud, or abuse?
2. ASN type — is this a datacenter, ISP, or mobile carrier?
3. Block consequences — if we block this IP, how many legitimate users do we affect?

For mobile carrier IPs under CGNAT, the math on point 3 is brutal for the website:

• Block a datacenter IP → affects 0 real users (only bots and proxy users)
• Block a residential IP → affects 1-5 households
• Block a mobile carrier IP → potentially affects thousands of real subscribers

A major e-commerce site cannot block 193.x.x.x (Kyivstar's mobile range) without denying access to thousands of legitimate Ukrainian mobile shoppers. A social network cannot block Orange Romania's LTE range without cutting off real Romanian users scrolling their feed on the bus.

This asymmetry is fundamental. It is not a loophole — it is a structural feature of how mobile internet is built.

Why Websites Can't Blacklist Mobile Ranges

Commercial IP reputation databases (Maxmind, IPQualityScore, Scamalytics) classify IPs into categories:

• Datacenter / Hosting
• Residential / Broadband
• Mobile / Wireless

Datacenter IPs get aggressively flagged and blocked. The entire AWS, DigitalOcean, and Hetzner IPv4 space is in every major blocklist.

Mobile IPs from real carriers are treated differently. The databases note them as mobile, but they carry low fraud scores because:

• Real abuse is limited — it's hard to run a botnet from actual SIM cards
• CGNAT makes attribution difficult — if 5,000 users share an IP, you can't assign reputation to the IP itself
• Carriers self-regulate — Kyivstar, Orange, and LMT have abuse desks and actively terminate accounts used for spam

The result is that mobile carrier IPs maintain consistently low fraud scores even as proxy providers use them commercially.

How This Works in Practice

Consider what happens when Facebook's trust system evaluates a login:

The CGNAT flag is not a negative signal — it tells the platform "this IP is used by many real mobile users." That is exactly what makes mobile proxies pass trust checks.

ASN: The Identifier That Matters Most

Every IP address block on the internet is assigned to an Autonomous System (AS), identified by an ASN (Autonomous System Number).

ASN data is public. Any platform can look up any IP and see immediately who owns it:

• AS16509 → Amazon AWS (datacenter)
• AS14061 → DigitalOcean (datacenter)
• AS15895 → Kyivstar (mobile carrier, Ukraine)
• AS8708 → Orange Romania (mobile carrier, Romania)
• AS12578 → LMT (mobile carrier, Latvia)

When your traffic exits through a ProxyGrow mobile proxy:

• The IP belongs to the carrier's ASN
• ASN lookup confirms it as a mobile operator
• CGNAT is expected and normal for that ASN
• The platform treats it as real mobile traffic

This is fundamentally different from any datacenter-based solution. You cannot fake an ASN. The IP either belongs to Kyivstar or it doesn't.

Mobile vs. Residential: The Reputation Difference

Residential proxies are sold as the premium alternative to datacenter proxies. And they are better — but they have a problem.

Residential proxy IPs have history.

Residential proxy networks source their IPs from real users who install apps or browser extensions. These IPs are used by the proxy network's clients for various purposes — some legitimate, some not. Over time, the IPs accumulate:

• Fraud history from other users
• Appearance in blocklists
• Bot-pattern associations

By the time you get a residential IP, it may have already been used to scrape, spam, or commit ad fraud by a previous user. You inherit that reputation.

Mobile carrier IPs under CGNAT are cleaner:

• The CGNAT model means individual IP reputation is diluted across thousands of real users
• Carriers rotate the public IPs among subscribers constantly (CGNAT table timeouts)
• There are no "previous users" of a specific IP in the traditional sense

What ProxyGrow's CGNAT Setup Means for You

ProxyGrow operates real USB modems with real SIM cards:

• Ukraine: Kyivstar, Vodafone, Lifecell — major carriers, CGNAT-enabled LTE/5G
• Romania: Orange, Vodafone, Digi — EU-based carriers, CGNAT-enabled LTE
• Latvia: LMT, Tele2, Bite — Baltic EU carriers, CGNAT-enabled 4G/LTE

When your traffic exits through a ProxyGrow proxy, it passes through the carrier's actual CGNAT infrastructure. The IP you get is the same class of IP used by thousands of real Ukrainian, Romanian, or Latvian mobile users.

The IP rotation works by triggering a reconnect on the modem, which causes the carrier's CGNAT system to allocate a new public IP from the pool. This is the same process that happens when a real user's phone reconnects after a call or after moving between towers.

Summary

Mobile proxies are not just "better residential proxies." They operate on a fundamentally different network layer — one that platforms built their trust systems around years before proxy services existed. CGNAT is not a hack. It's carrier infrastructure, and mobile proxies let you use it legitimately.