A method is provided for establishing a secured connection and to corresponding SFC equipment, CFM equipment, and terminal requiring a computer software program. More specifically, a method is provided for transmitting a multimedia flow from or to a terminal, that includes: a step of establishing a signalling between the terminal and a signalling flow control equipment; and a step of implementing, between the terminal and a multimedia flow control equipment, a mechanism for crossing an address translation equipment. The method further includes a step of checking that the terminal requiring execution of the implementation step, is the same terminal as the one involved in execution of the signalling establishment step.