But I need send request from web application to client application.
IF the web app has to create a request, it is no longer acting as a server but as a client.
IF the "client" has to be prepared to accept a request, it is acting as a server.
Perhaps
you should consider a different architecture - how often do you need to "talk to" the client apps?
Why cant the "client" send a request to see if new data is available.
Bill