What is cgnat?

Carrier-grade Network Address Translation (CGNAT) is a technology used by internet service providers (ISPs) to manage the limited availability of IPv4 addresses by allowing multiple customers to share a single public IP address. This is necessary as the supply of IPv4 addresses is running out due to the exponential growth of internet-connected devices.

CGNAT works by assigning a unique private IP address to each customer's device and translating it to a shared public IP address when communicating with the internet. It also manages the translation of multiple private IP addresses into a smaller pool of public IP addresses to optimize resource utilization.

While CGNAT helps conserve IPv4 addresses, it can also introduce certain challenges such as reduced network performance, difficulty in hosting services that require public IP addresses, and potential issues with certain applications and protocols that may not be compatible with NAT.

Overall, CGNAT is a crucial technology for ISPs to continue providing internet connectivity to their customers in the face of IPv4 exhaustion until the full transition to IPv6, which offers a significantly larger address space, is completed.