Patent ID: 8522317

Claim:
A device for maintaining an address translation table, placed in series between a user terminal and a third-party entity of a telecommunications network, the device comprising a hardware processor programmed: to intercept a registration request message sent by the user terminal to the third-party entity using an application signaling protocol, the registration request message being received by the device at a first reception time at a reception port dedicated to the exchange of messages using the application signaling protocol; to verify the existence in the address translation table of an entry specific to the exchange of application signaling messages using the application signaling protocol between the user terminal and the third-party entity; and if there is no entry specific to the exchange of application signaling messages using the application signaling protocol between the user terminal and the third-party entity: to create a specific entry in the address translation table associating the following with a private address and a private port of the user terminal in a private network connecting the terminal to the device: a) a public address and a public port of the user terminal in the telecommunications network: and b) an indication of the validity of the specific entry, wherein: the validity indication of the specific entry takes into account the first reception time and a first validity period, and the first validity period has a predetermined value that is specific to the application signaling protocol.