Error when switching from local host IP to true IP

Question

I'm using the basic java.net.ServerSocket and java.net.socket arrangement to make a very simple chat program (planning to build a mutlithreaded client/server a little bit later). For most of my testing, I've specified the IP for the client socket to connect to as:
Socket mySock = new Socket("127.0.0.1", 10101);
This would always work. However, when I moved to using this
Socket mySock = new Socket("xxx.xxx.xx.xxx", 10101);
or
Socket mySock = new Socket(InetAddress.getByName("xxx.xxx.xx.xxx"), 10101);
Both the server and the client blocked before this point:
Client -> See above lines (creating socket)
Server -> Socket sock = myServerSocket.accept();
Both the client and server are executing on the same machine. If I move the client to a different machine, while it connect properly then? Would a firewall block execution of this class in this manner?

Answer 1

If the server program is running on a machine at port PP whose IP address is xxxxx and you have a html page that resides in the same directory as the server and the client, and the html page properly refers the client class, then there shudn't be any problem in accessing the applet using http://xxxxxx/myhtml.html Check each and everything one by one.
-Uday