Edit I talked [censored] here - no sleep for 48 hours.
If your router's external IP address is in the range of 100.64.0.0/10 ie begins 100.64. through 100.127. then you are on CGNAT.
To explain CGNAT first consider a normal IPv4 connection.
A domestic router will be allocated a unique IP address. The router provides a private network behind the router with a network range something like 172.16.0.0/24 Millions of domestic installations use the same private network number, private to just them as all communication outside the network is done using the routers allocated public address. The domestic router has to remember which private IP address is expecting what reply so it can translate incoming traffic and pass it on.
Now that there are no new IPv4 addresses to be bought by newer ISPs they have to use IPv6 addresses but IP address ranges cost money. To save money they perform the same Nat process but further up the chain. They allocate a private IPv6 address from that 100.64.0.0/10 range to the outside of your router and all traffic from your router is translated into a unique public IPv6 address further into their network. Unique in that it exists only once on the internet but is being used by multiple customers who all share the same unique IPv6 address.
This means they can use the same private IPv6 address range multiple times across their network. The drawback is that the eventual public IPv6 address is being used by multiple users. A powerful router somewhere on their network is storing information on what traffic is coming from their private network so it can pass back their replies. This results in a small rise in latency which probably goes unnoticed by most users.
Have a look at
https://itigic.com/know-if-my-internet-connection-us...

A friend surfing in

Edited by Moto (Wed 09-Oct-24 21:43:04)