A method for protecting a communication network, through which a client communication device is adapted to establish a state connection according to a state transport protocol with a server communication device, and to transmit data packets thereto, said method being characterised in that it comprises the following steps intended to be implemented by a control device of the communication network: - prior installation of at least a first rule, so-called initial rule (RIm), including the following substeps: ∘ obtaining identification information of at least one connection (Cm) authorised by a network administrator; ∘ transmitting to the switching device said at least one initial rule (RIm) for processing a data packet of said at least one connection (Cm), comprising at least first identification information of the authorised connection, information representative of a connection initiation event and an action of retransmitting the data packet to the control device; - Receiving a request message (RQ, RQ', RQ"), said message comprising at least identification information of the connection and at least one piece of information representative of a connection event, said message having been sent by a switching device of the network, by applying a first rule for processing a data packet sent by the client device to the server device; - Obtaining a current state (Si) by searching a connection table for an input associating said current state with said identification information of the connection; - Updating the current state (Sj) of the connection from said at least one piece of information representative of a connection event and a state automaton of the transport protocol; - Sending to said switching device a response message (RP, RP', RP") comprising: ∘ second rules (Rij) for processing a data packet of the connection, such a second rule being associated with a possible transition (Tij) from the updated current state (Sj) and comprising the identification information the connection, at least one piece of information representative of a connection event and information representative of an action to be triggered to process said data packet; and a command for deleting the first processing rules, associated with the previous transitions of the connection. - prior installation of at least a first rule, so-called initial rule (RIm), including the following substeps: ∘ obtaining identification information of at least one connection (Cm) authorised by a network administrator; ∘ transmitting to the switching device said at least one initial rule (RIm) for processing a data packet of said at least one connection (Cm), comprising at least first identification information of the authorised connection, information representative of a connection initiation event and an action of retransmitting the data packet to the control device; ∘ obtaining identification information of at least one connection (Cm) authorised by a network administrator; ∘ transmitting to the switching device said at least one initial rule (RIm) for processing a data packet of said at least one connection (Cm), comprising at least first identification information of the authorised connection, information representative of a connection initiation event and an action of retransmitting the data packet to the control device; - Receiving a request message (RQ, RQ', RQ"), said message comprising at least identification information of the connection and at least one piece of information representative of a connection event, said message having been sent by a switching device of the network, by applying a first rule for processing a data packet sent by the client device to the server device; - Obtaining a current state (Si) by searching a connection table for an input associating said current state with said identification information of the connection; - Updating the current state (Sj) of the connection from said at least one piece of information representative of a connection event and a state automaton of the transport protocol; - Sending to said switching device a response message (RP, RP', RP") comprising: ∘ second rules (Rij) for processing a data packet of the connection, such a second rule being associated with a possible transition (Tij) from the updated current state (Sj) and comprising the identification information the connection, at least one piece of information representative of a connection event and information representative of an action to be triggered to process said data packet; and a command for deleting the first processing rules, associated with the previous transitions of the connection. ∘ second rules (Rij) for processing a data packet of the connection, such a second rule being associated with a possible transition (Tij) from the updated current state (Sj) and comprising the identification information the connection, at least one piece of information representative of a connection event and information representative of an action to be triggered to process said data packet; and a command for deleting the first processing rules, associated with the previous transitions of the connection.