What Is CGNAT (Carrier-Grade NAT)?
CGNAT (Carrier-Grade NAT or Large-Scale NAT) is a technology used by Internet Service Providers (ISPs) to route multiple subscribers to the internet through a single public IPv4 address. CGNAT is a solution developed to address IPv4 address exhaustion and is widely used in many countries, including Turkey, as of 2026.
In a normal internet connection, each subscriber is assigned a unique public IP address. However, with CGNAT, hundreds or even thousands of subscribers share the same public IP address. The ISP creates an additional NAT (Network Address Translation) layer in its network to route subscriber traffic through a single IP.
How Does CGNAT Work?
Technical Architecture
CGNAT creates a two-layer NAT structure:
# CGNAT Layers
Subscriber Device (192.168.1.x)
|
v [1st NAT: Home Modem/Router]
ISP Private Network (100.64.x.x - RFC 6598)
|
v [2nd NAT: ISP CGNAT Device]
Internet (Public IP: 85.xxx.xxx.xxx)
|
v
Target Server (example.com)Port Allocation
The CGNAT device allocates specific port ranges of the public IP to each subscriber:
- Subscriber A: 85.xxx.xxx.xxx:1024-2047
- Subscriber B: 85.xxx.xxx.xxx:2048-3071
- Subscriber C: 85.xxx.xxx.xxx:3072-4095
Problems Created by CGNAT
1. IP Bans and Account Blocking
CGNAT's biggest problem is that one subscriber's bad behavior affects all subscribers sharing the same IP. If one person sends spam or gets banned on a site, hundreds of users sharing that IP can be affected.
2. Gaming and P2P Connections
CGNAT causes issues with applications requiring NAT traversal. "Strict NAT" or "NAT Type 3" warnings in online games indicate CGNAT. This leads to connection problems in multiplayer games.
3. Port Forwarding
Port forwarding is not possible behind CGNAT. Applications requiring external access — home servers, NAS access, IP cameras — will not work.
4. Increased Latency
The additional NAT layer adds processing time to each packet. This delay is typically 1-5ms but can be noticeable in gaming and live streaming.
CGNAT and Proxy Requirements
Problems created by CGNAT can make proxy usage essential:
Unique IP Requirement
Behind CGNAT, you share an IP with other subscribers. If you share an IP with a banned user, you get blocked too. Using an ISP proxy gives you a dedicated, unique IP address.
Gaming and Automation
The most effective way to solve CGNAT-caused Strict NAT issues in online games is connecting through a proxy. ProxyTurk's SOCKS5 proxies help overcome NAT issues in games.
Business and Professional Use
For professional users (web scraping, social media management, SEO), CGNAT is a serious obstacle. Using dedicated IPv4 proxies is standard practice in these areas.
CGNAT Solutions
- Request a real IP from your ISP: Some ISPs offer static or dynamic real IP addresses for an additional fee
- Use IPv6: IPv6 address space is practically unlimited, eliminating the need for CGNAT
- Use proxies: Get a dedicated IP address with an ISP proxy to escape CGNAT issues
- Use VPN: A VPN connection bypasses CGNAT by routing through the VPN server's IP
- Switch ISPs: Move to an ISP that does not use CGNAT or offers real IPs
IPv4 Exhaustion and the Future
CGNAT's fundamental cause is IPv4 address exhaustion. IPv4 provides a total of 4.3 billion addresses, but as of 2026, internet-connected devices exceed 30 billion. This imbalance makes CGNAT necessary.
The long-term solution is IPv6. With IPv6, 340 undecillion (340 x 10^36) addresses are available — practically unlimited. However, IPv6 transition is progressing slowly, and CGNAT is expected to continue being used in the coming years.
Frequently Asked Questions (FAQ)
How do I know if I am behind CGNAT?
Compare your modem's WAN IP address with the IP address seen from the internet. If they differ, you are behind CGNAT. Also, if your WAN IP is in the 100.64.0.0/10 range (100.64.x.x - 100.127.x.x), CGNAT is definitely being used.
Does CGNAT affect gaming ping?
Yes, CGNAT can add 1-5ms additional latency due to the extra NAT layer. NAT type issues (Strict/Type 3) can also reduce multiplayer connection quality.
Does CGNAT increase the need for proxies?
Yes, users behind CGNAT experience more frequent IP bans, speed throttling, and access blocks due to shared IPs. Proxy usage solves all these problems.