MulticastSocket problem

Question

hi
i'm trying to build a chat application and i have problems with multicast sockets. i.e. when 2 clients are connected to server, the client on wich machine the server is running can see what other client is typing, but the other client can't.
here's the code for the multicastsocket:
socketM=new MulticastSocket(4446);
netIf1=NetworkInterface.getByName("eth0");
netIf2=NetworkInterface.getByName("eth1");
netIf3=NetworkInterface.getByName("eth2");
socketM.joinGroup(group,netIf1);
socketM.joinGroup(group,netIf2);
socketM.joinGroup(group,netIf3);if someone could help me with this i would appreciate

Answer 1

i've deleted the line socketM.joinGroup(group,netIf3);this is how the application should work:
every client sends a packet to the server. the server receives the packet and decides what to do next.
code for sending a packet to the server:
msg="0<"+nickname2+"> "+vText.get(0).getText();
buf=msg.getBytes();
packet=new DatagramPacket(buf,buf.length,address,4445);
try {
       socket.send(packet);
catch(IOException exc) {
       System.err.println("IO exception");
vText.get(0).setText(null);where msg is a String, buf is byte[], vText is Vector<JTextField>.
code for receiving a packet from the server:
packet=new DatagramPacket(buf,buf.length);
socketM.receive(packet);
msg=new String(packet.getData(),0,packet.getLength());
vTxtArea.get(0).append(msg+"\n");where socketM is MulticastSocket, vTxtArea is Vector<JTextArea>.
code for sending a packet from the server to the clients:
group=new InetSocketAddress("230.0.0.1",4446);
//receive a packet from a client
byte[] buf = new byte[256];
DatagramPacket packet=new DatagramPacket(buf, buf.length);
socket.receive(packet);
String dString=new String(packet.getData(),0,packet.getLength());
//send a packet to the clients
buf=dString.getBytes();
packet=new DatagramPacket(buf,buf.length,group);
MulticastSocket sock=new MulticastSocket();
sock.send(packet);
sock.close();i can't find any errors. if you have any ideea why this doesn't work please let me know.