A session processing module for a server is adapted to communicate across the Internet with a plurality of clients. The processing module runs within a servlet and allocates a session identifier in response to a first input stream of a session between a client and the server; negotiates communication characteristics for the session; and instantiates, according to the communication characteristics, routines for processing subsequent session input streams containing request data and routines for generating session output streams containing response data. A variable depth of penetration to be applied to a dynamically specified quality of service for a session is enabled. Thus, in one embodiment the module relays encrypted request data for a session to a back-end server, and receives from the back-end server encrypted response data for the session for the client. Alternatively, the module itself decrypts input streams containing request data and processes the data to generate output streams containing encrypted response data for the client.