Well i even changed multi cast addr and port in cluster-service.xml in both machines but i still get the following error. 16:41:28,828 WARN [UDP] packet from 192.168.1.6:3431 has different version (12338) from ours (23). This may cause problems 16:41:28,828 ERROR [UDP] failed unmarshalling message java.io.EOFException at java.io.DataInputStream.readFully(DataInputStream.java:180) at org.jgroups.stack.IpAddress.readFrom(IpAddress.java:268) at org.jgroups.Message.readFrom(Message.java:606) at org.jgroups.protocols.TP.bufferToMessage(TP.java:982) at org.jgroups.protocols.TP.handleIncomingPacket(TP.java:838) at org.jgroups.protocols.TP.access$200(TP.java:44) at org.jgroups.protocols.TP$IncomingPacketHandler.run(TP.java:1290) at java.lang.Thread.run(Thread.java:619) "bstansberry(a)jboss.com" wrote : On your network you have a process using a different version of JGroups. Find that process and change its version to match yours, or change your multicast address and port so your channel doesn't see the packets from the other process. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4076751#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...