Yes, this problem would only occur in 4.2 and later. In 4.2, if you don't pass -b at startup, JBoss will almost all services (e.g. JNDI) to 127.0.0.1. This is a security precaution; basically the server is not remotely available unless you say you want it to be. An exception to this is JGroups channels, which will communicate using the default interface if you don't set -b. This allows servers to cluster. So, your servers clustered. For services based on the HAPartition (e.g. HASingleton) the nodes in the cluster are identified by taking the IP address and port that the JNDI service is bound to. I won't go into the details as to why this is, other than to say the goal is to detect/prevent the same node joining the group twice. This breaks down if the nodes in the group are all binding JNDI to localhost, since every node has the same id!! You can see this in your log: 2007-09-24 07:37:55,512 INFO [org.jboss.ha.framework.interfaces.HAPartition.lifecycle.DefaultPartition] New cluster view for partition DefaultPartition (id: 1, delta: 1) : [127.0.0.1:1099, 127.0.0.1:1099] Having two nodes with the same id like that must be messing up the master node election process. Hence my suggestion to use -b. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4091794#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...