Carrier-Grade NAT (CGNAT)

Carrier-Grade NAT, or CGNAT, is a technology that allows multiple customers of an internet service provider to share public IPv4 addresses. The provider translates private IP addresses from different customer networks into one or more public IPv4 addresses. CGNAT therefore extends the principle of Network Address Translation (NAT) to the service provider’s infrastructure. It is primarily used to address the limited availability of public IPv4 addresses. As several connections can share the same public IP address, direct inbound connections and certain applications may be restricted. This can affect services such as self-hosted servers, port forwarding, VPN connections and selected online applications. In the long term, the increasing adoption of IPv6 reduces the need for CGNAT.