Your "ConnectionTable" logging: | 09:02:22,093 WARN [ConnectionTable] peer closed connection, trying to re-send msg | 09:02:22,093 ERROR [ConnectionTable] 2nd attempt to send data failed too is coming from the JBoss Messaging Data Channel. That channel uses TCP unicast for sending messages, unlike the other channels that use UDP multicast. Farming doesn't use that channel; it uses a different one, the UDP multicast-based one from cluster-service.xml. So, two separate channels using different underlying protocols are experiencing problems, which sounds to me like a network or host configuration problem. Hard to say what; if resolving the firewall issues you raise in a separate thread make it go away, there's your answer. See also http://www.jboss.org/community/docs/DOC-12375 View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4203715#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...