How to send a packet from client to client without using a server?

Question

Java

You need to connect to the client, send him a message and close the connection. Google has a wagon of making client-server chats. And how easy is it to send a message to one client, knowing the IP and port?

Answer 1

You are confusing a software server and a hardware one. A server in a data center is not the same as a web server or a chat server. You need a server program that will run on the client's computer.

Answer 2

Google has a wagon of making client-server chats. And how easy is it to send a message to one client, knowing the IP and port?

Port of what? Someone needs to listen on this port, and what it does is called a server.
Answer to the question: no way.