According to one or more embodiments of the present invention, a proxy server includes a memory and a communication unit. The memory is configured to store and retrieve a client device identifier and an associated client device transport address, while the communication unit is configured to send and receive messages. The communication unit is configured to receive an identification message according to a first protocol from a client device through at least one intermediate network address translator (NAT). The identification message includes the client device identifier and conveys the client device transport address. The communication unit is configured to receive a request message from an admin device including the client device identifier. The proxy server is configured to retrieve the associated client device transport address and instruct the client device to open a connection with the proxy server according to a second protocol that is different from the first protocol.