I get a communication link failure while application tries to establish a connection with DB. [#|2010-04-08T20:09:57.825+0300|SEVERE|glassfish3.0|javax.enterprise.system.std.com.sun.enterprise.v3.services.impl|_ThreadID=24;_ThreadName=Thread-1;|Cannot connect to database server = com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.|#] Precisely at this string: Statement s = conn.createStatement(); where conn is defined as follows: private static java.sql.Connection conn; For this app I have set a connection pool with default parameters and currently it (app) uses both JPA and direct JDBC queries. Recreation of connection pool gave nothing, connection pool ping gave next message: Ping Connection Pool for pool is Failed. Ping failed Exce ption - Connection could not be allocated because: Communications lin k failure%%%EOL%%%%%%EOL%%%The last packet sent successfully to the s erver was 0 milliseconds ago. The driver has not received any packets from the server. Please check the server.log for more details.%%%EOL %%%Ping failed Exception - Connection could not be allocated because: Communications link failure and flushing the connection pool gave: com.sun.enterprise.admin.cli.CommandException: remote failure: Failed to flush connection pool ... However I can connect to the database from a terminal. Besides I have the same app working on my local machine with identical connection pool settings. Any one has an idea on whats going on or how to solve the trouble?