Controlling communications

A method for use in a packet-based communication system implemented over a public packet-based network comprising a public-network server and a plurality of public-network user terminals, and a private packet-based network comprising a private-network server and a plurality of private-network user terminals each installed with a public-network communication client, the method comprising:

• receiving a login request from a public-network client of a private-network user terminal;
• in response to the login request, initiating both a private-network authentication procedure involving the private-network server and a public-network authentication procedure involving the public-network server;
• subject to both authentication procedures, enabling establishment of a communication channel between one of the public-network user terminals and the public-network client of the private-network user terminal;
• and
• applying a control policy to communications occurring over said channel, the control policy originating from the private-network and configured to include at least one policy associated with identifying at least one condition associated with blocking a communication over said channel.

A computer program product for use in a packet-based communication system implemented over a public packet-based network comprising a public-network server and a plurality of public-network user terminals, and a private packet-based network comprising a private-network server and a plurality of private-network user terminals each installed with a public-network communication client, the computer program product comprising code embodied on computer-readable storage memory and configured so as, responsive to execution on a gateway between the public and private networks, to:

• receive a login request from a public-network client of a private-network user terminal;
• in response to the login request, initiate both a private-network authentication procedure involving the private-network server and a public-network authentication procedure involving the public-network server;
• subject to both authentication procedures, enable establishment of a communication channel between one of the public-network user terminals and the public-network client of the private-network user terminal;
• and
• ensure a control policy is applied to communications occurring over said channel, wherein to ensure the control policy is applied to communications comprises an ability to transfer the control policy to at least one private-network user terminal of the plurality of private-network user terminals.