How can you determine the type of user's connection to the Internet?

Question

Telecommunications

Purpose of the task. A person visits a certain web page and receives information about the type of his connection. By type, I mean: direct connection, home router, or ISP's LAN.
I know how to distinguish a direct connection from an internal network, but I have no idea how to distinguish a connection through a home router from a NAT provider.

Answer 1

But no way. The router itself is a NAT, and then there may be a bunch of NATs, including the provider.