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Carrier Grade NAT

A large-scale NAT implemented by ISPs to share a small pool of public IPv4 addresses among a very large number of customers.

AbbreviationCGNAT
Categorynetwork

Overview

Carrier Grade NAT (CGNAT), also known as LSN (Large Scale NAT), is a solution used by ISPs to combat IPv4 address exhaustion. Instead of giving every customer a public IP, the ISP assigns customers private IPs and performs NAT at the core of their network.

Challenges

  • Double NAT: Can cause issues with online gaming, VPNs, and hosting services at home.
  • Traceability: Makes it harder for law enforcement to identify a specific user based on an IP address.
  • Performance: Adds latency and processing overhead at the ISP level.