--- OnlineHelp --- Using Radius authentication When you set the option Authentication to "Radius", users will be authenticated with an external RADIUS authentication server. You must configure the parameters of the server in System->User Authentication first. The RADIUS server MUST support MSCHAPv2 challenge-response authentication. The server can pass back parameters like client IP address and DNS/WINS server addresses. When Radius server authentication is active, it is not possible to authenticate local users with PPTP any more. ---