Carrier-grade Network Address Translation (abbreviated as CGNAT) is an IP address provisioning method using a private IP address block used by Internet Service Providers where IPV4 is limited. PLDT sometimes uses this method of IP address allocation in newer DSL installations, though usage in Fibr networks have also been reported.
While irrelevant to normal consumers, this kind of IP address provisioning presents serious problems to services reliant on port forwarding.
PLDT rivals Globe Telecom and Converge ICT extensively uses CGNAT as well.
How it worksEdit
Think of CGNAT as your consumer router. When you connect, it gives you a private IP address block. For consumers, our router gives us an IP block of 192.168.0.X where X is a number from 2 to 254, depending on the configuration.
For CGNAT, it uses 10.x.x.x and cannot be seen outside the network.
ISPs uses this method to reduce IPV4 exhaustion. IPV6 is aimed to eliminate reliance on private IP address blocks.
PLDT currently has no plans to use IPV6 yet.