i don't know can a port has multi socket.
i found two views:
1.一个端口可以有多个socket，但其中只能有一个处于listen状态。这就是accept后可以用oldsock监听同时用newsock通信的基础
2.监听socket监听的是指定端口，一旦accept了新的socket，那么新socket使用另一个自由端口（通常16384－32767）与client进行通讯，而原有socket依然可以继续监听指定端口。
i don't know which is right because that there has a contradiction with first is user one port and the other user multi ports!
i found two views:
1.一个端口可以有多个socket，但其中只能有一个处于listen状态。这就是accept后可以用oldsock监听同时用newsock通信的基础
2.监听socket监听的是指定端口，一旦accept了新的socket，那么新socket使用另一个自由端口（通常16384－32767）与client进行通讯，而原有socket依然可以继续监听指定端口。
i don't know which is right because that there has a contradiction with first is user one port and the other user multi ports!