I have jboss 4.0.2 running on my ubuntu linux server. I have 5.0.1 mysql and the 3.0.1 mysql-connector My datasource gets registered ad MySqlDSL and in the jmx console it says bind name java:MySqlDSL So far so good. I my war application (i connect using ) this Statement stmt =null ; ResultSet rs = null; boolean test = false ; try { InitialContext ctx = new InitialContext(); DataSource ds = (DataSource)ctx.lookup("java:/MySqlDSL"); con = ds.getConnection(); con.setAutoCommit(false); con.setTransactionIsolation(con.TRANSACTION_SERIALIZABLE) ; stmt = con.createStatement(); StringBuffer sb = new StringBuffer() ; sb.setLength(0) ; Jboss throws and exception JbossManagedConnectionPool throwable while attempting to get a new connection: null communications lik failure du to underlying exception java.net.ConnectException Connection refused my connection-url string is <connection-url>jdbc:mysql://localhost:3305/tracker my username and password are correct. I try this on the command line and I can login. Any idea? Thanks a million if you answer. Ron View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3998558#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...