Java 应用程序可以连接到特定的 ip 和端口，但端口未在防火墙中打开

Question

The following java code listens for incoming connections on a specific port. I see that clients can connect but how is that possible if the server port is not open in the firewall?

ServerSocket serverSocket = new ServerSocket();
InetSocketAddress addr = new InetSocketAddress("localhost", 5555);
serverSocket.bind(addr);

Thank you.

Answer 1

I see that clients can connect

Only if those clients are in the same localhost, because your server port is bound to 127.0.0.1:5555, not 0.0.0.0:5555.

but how is that possible if the server port is not open in the firewall?

Because the firewall doesn't have anything to do with communications within the localhost.