A telecommunication method, - wherein a communication connection, initiated and controlled by the Session Initiation Protocol provided by an SIP server (16, 24), is established from and/or to a communication terminal (10, 12), - wherein, initiated by the communication terminal (10, 12), a function address in the form of an SIP protocol element for calling up at least one function of the SIP server (16, 24) that can be assigned to the respective communication connection and is at least temporarily available is generated dynamically, - wherein the SIP protocol element serves as the target address for an SIP message to the SIP server (16, 24) for calling up the function, and - wherein the SIP protocol element is generated dynamically by a gateway (20, 22) that is providing the respective function, • wherein the communication terminal being called in the respective communication connection (B, 12) calls up the respective function of the gateway (20, 22), • wherein the communication connection is established via the gateway (20, 22) that generates the function address, wherein the function address generated at the gateway comprises the gateway address and/or an identifier for the communication connection to be established, and • wherein the temporarily generated SIP protocol element is sent as a Malicious Call Identification "MCID" call-up from the communication terminal (B, 12) being called to the gateway (20, 22) for calling up the respective function. - wherein a communication connection, initiated and controlled by the Session Initiation Protocol provided by an SIP server (16, 24), is established from and/or to a communication terminal (10, 12), - wherein, initiated by the communication terminal (10, 12), a function address in the form of an SIP protocol element for calling up at least one function of the SIP server (16, 24) that can be assigned to the respective communication connection and is at least temporarily available is generated dynamically, - wherein the SIP protocol element serves as the target address for an SIP message to the SIP server (16, 24) for calling up the function, and - wherein the SIP protocol element is generated dynamically by a gateway (20, 22) that is providing the respective function, • wherein the communication terminal being called in the respective communication connection (B, 12) calls up the respective function of the gateway (20, 22), • wherein the communication connection is established via the gateway (20, 22) that generates the function address, wherein the function address generated at the gateway comprises the gateway address and/or an identifier for the communication connection to be established, and • wherein the temporarily generated SIP protocol element is sent as a Malicious Call Identification "MCID" call-up from the communication terminal (B, 12) being called to the gateway (20, 22) for calling up the respective function. • wherein the communication terminal being called in the respective communication connection (B, 12) calls up the respective function of the gateway (20, 22), • wherein the communication connection is established via the gateway (20, 22) that generates the function address, wherein the function address generated at the gateway comprises the gateway address and/or an identifier for the communication connection to be established, and • wherein the temporarily generated SIP protocol element is sent as a Malicious Call Identification "MCID" call-up from the communication terminal (B, 12) being called to the gateway (20, 22) for calling up the respective function.