How does residential broadband distinguish between static IP and dynamic IP?

Residential broadband is generally a static IP, which is shared by the whole community, but it is estimated that it is a dynamic IP obtained automatically when it is used by itself.

But the computer connected to the server is static IP, which can be specified on the server or seen on the router when installing telecom.

Static IP, as long as the specified IP of the telecom is input correctly, you can access the Internet without dialing, and you need to dial dynamically, so you can only get the IP automatically.