Hi, Running JBossAS 4.x, and JBossMQ on RH-Linux. Our application is a multi-process app, where processes interact over JMS topics and Queues. I am seeing the following exceptions thrown from the JBoss process in some of our installations, very occasionally: Connection failure: org.jboss.mq.SpyJMSException: Connection Failed; - nested throwable: (java.io.IOException: ping timeout.) ...and... org.jboss.mq.SpyJMSException: Cannot authenticate user; - nested throwable: (java.net.NoRouteToHostException: No route to host) I have seen other postings describing similar situations, but never describing a specific cause/solution. One posting stated that they could reproduce the "NoRouteToHostException" if they disconnected their server from the network. Why would connectivity to the network cause JMS to throw exceptions when supporting inter-process comm within the same host? Does JBossMQ get impacted by the server-OS DHCP/DNS operation/configuration? The "java.io.IOException: ping timeout" is described in http://wiki.jboss.org/wiki/Wiki.jsp?page=IGetIOExceptionPingTimeoutHowDoI... Here is says that large JMS messages and/or heavy paging could cause this. I have been able to create a ping timeout by changing the Linux date/time via the shell! Any insights would be greatly appreciated. Thanks, NBirch View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4121395#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...