The <simpleAuthenticationPlugin> seems caused broker network malfuntion.

Easy to reproduce: 1. Unzip "jboss-a-mq-6.2.1.redhat-084.zip" on two seperated machine A and B. 2. Uncomment A-MQ/etc/users.properties --> "admin=admin,..." line. 3. Edit activemq.xml from A and keep B's intact: <networkConnectors> <networkConnector userName= "admin" password= "admin" uri= " static :(tcp: //IP_A:61616,tcp://IP_B:61616)" duplex= " true " /> </networkConnectors> 4. Start AMQ from A and B, log shows: Network connection between vm: //amq#xx and tcp://IP_A:61616@xx (amq) has been established. --- Network connection between vm: //amq#xx and tcp://IP_B:61616@xx (amq) has been established. 5. If added below attrributes in A's activemq.xml: <simpleAuthenticationPlugin anonymousAccessAllowed= " true " > <users> <authenticationUser username= "admin" password= "admin" groups= "manager,viewer,Operator,Maintainer,Deployer,Auditor,Administrator,SuperUser,admin,anonymous" /> </users> </simpleAuthenticationPlugin> Error as below will appear in A's log: 137 - org.apache.activemq.activemq-osgi - 5.11.0.redhat-621084 | Network connection between vm: //amq#20 and tcp:///IP_B:61616@48671 shutdown due to a local error: javax.jms.InvalidClientIDException: Broker: amq - Client: NC_amq_inbound_amq already connected from vm://amq#4 6. No matter how we set <simpleAuthenticationPlugin>, brokers are not able to establish connection.