How exactly does a Server Socket work?

Question

How exactly does a Server Socket work? When I create a java server socket and accept connection at port 1234. Does the server actually uses the port 1234 for all clients? I've read that when you write a network server the socket actually opens another port once the connection is accepted.

Is this true? If so, why am I not seeing it in netstat? I see a lot of connections like this

tcp        0      0 ::ffff:MY_IP:1234 ::ffff:97.37.134.95:39236   ESTABLISHED 
tcp        0      0 ::ffff:MY_IP:1234 ::ffff:89.204.153.101:26117 ESTABLISHED 
tcp        0      0 ::ffff:MY_IP:1234 ::ffff:195.240.16.70:26193  ESTABLISHED 
tcp        0      0 ::ffff:MY_IP:1234 ::ffff:80.187.98.116:15012  ESTABLISHED 
tcp        0      0 ::ffff:MY_IP:1234 ::ffff:218.78.248.190:30794 ESTABLISHED 

So are they really all connected to my server at 1234? If so, doesn't that mean you the server will be able to accept infinite number of connections?

Answer 1

So are they really all connected to my server at 1234?

Yes

If so, doesn't that mean you the server will be able to accept infinite number of connections?

You can have 2^32-2-1 (IP4) addresses (leave one free to have another host on the same network), and 2^16 remote socket ports. That is a lot, but not infinite. Anyway you will run out of memory before.

Answer 2

TCP/IP Sockets are uniquely identified by the tuple (local Address, local port, remote address, remote port).

This will provide for a very large number of sockets, but not infinite.