Web Server, Reverse Proxy, Load Balancer

Reverse proxies can operate wherever multiple web-servers must be accessible via a single public IP address.

The web servers listen on different ports in the same machine, with the same local IP address or, possibly, on different machines with different local IP addresses. The reverse proxy analyzes each incoming request and delivers it to the right server within the local area network.

Public IP address: the Internet Protocol address, logged by various servers/devices.   This is when you connect to these devices through your internet connection.

1) Same machine, same local IP address.

2) different machines, different local IP address within the local area network.

Reference:

https://en.wikipedia.org/wiki/Reverse_proxy