Problem with Socket and dynamic IP

Question

The problem I have is the following: My domain has a dynamic IP, so after the IP changes the s.accept() does not work any more!
try // Point 1 *)
ServerSocket s = new ServerSocket(portNumber);
for(;;)
Socket incoming = s.accept(); // does not work after IP changes
new ThreadedEchoHandler(incoming, i).start();
So I have to detect that the IP has changed and have to start again at Point 1
How can I do this?
thx walter

Answer 1

Something is vary wrong with your network software if your getting an error on that.
When you start your computer connected to the network, a DHCP (in your case) Server sends your NIC a dynamic IP address, we call this process "binding". When the client computer connects it also is given an IP address to bind to. You can't connect to anything, or in your case create a ServerSocket, if you dont even have an IP. So your Server has an IP address, and so does the client. You should not be getting any errors unless the client/server network is using two different protocols. You can't run an IPX/SPX network and a TCP/IP network together without a Bridge.
That does not seem to be your problem. I believe, then, that the problem is that your ThreadedEchoHandler is holding the CPU. Instead of having a client connect (s.accept()) outside of that thread. Have the thread be created by using the arugment of the ServerSocket instead and no the Socket object created.
new ThreadedEchoHandler(ServerSocket ss);
Then let it do it's thing. Also, you will need to call it's start() method to actually run the thread as a thread. Otherwise it runs as a simple class.