Disclosed is a processing method for processing a received message coming from a first device and sent to a second device managed by a multimedia IP core network, the method being for implementation by a processor entity when the received message is a message for discovering the capabilities and the status of the second device. In some embodiments, the processing method comprises obtaining an identifier of the first device from a field in the received discovery message and acting as a function of said identifier to select a response mode for responding to the received discovery message, the mode being selected from a predefined set containing at least two response modes.