Method and apparatus to control application messages between a client and a server having a private network address

A method to control communication traffic in a communication network, said traffic comprising application-level messages between a client (30, 30',30'') and a server (10, 10', 10'') having a private network address (IPreal). The method comprises the steps of: sending by the client (30, 30',30'') a request message requesting a service to the server (10, 10', 10'') using a first public network address (IPoId) associated to the server (10, 10', 10''); processing the request message at an intermediate logic unit (20, 20',20'') logically positioned between said client (30, 30', 30'') and the server (10, 10', 10''); receiving an alert signal at said intermediate unit (20,20',20''). Upon receipt of aid alert signal the method provides for: mapping the private network address (IPreal) of the server to a second public network address (IPnew) associated to the server (10,10',10''); instructing the client (30,30',30'') to send the request message to the second public network address (IPnew) of the server (10, 10', 10'')