Authentication is essential so that the connection partners can be sure that it is the expected communication partner at the other end of the connection, with which a data is going to be exchanged. Currently only the server authentication is supported. This means that the client (SIMATIC AX Tools), which connects to the server (PLC), checks the server's identity by comparing the certificate sent by the server (PLC) with a reference. If the reference does not clearly indicate that the sender of the certificate is also the desired communication partner, then it is considered as an authentication error and the user must decide whether the connection should be established or aborted.
SIMATIC AX uses TLS communication to achieve server-authentication via verification of the certificate provided by the PLC. Therefore, it is mandatory to import a TLS certificate via import-certificate command.