Hi all, I have to find a solution that integrates the use of OTP (One Time Password ) as a second factor authentication in addition to the first factor authentication (witch is generally username and password) to an existing authentication System. This solution should be integrated easily to the existing authentication system regardless the protocol used for authentication (Rdius, Kerberos, Http, EAP, etc) and regardless the OS. My questions are: 1- What are the possibilities and the facilities offered by FreeRadius?? 2- I though about tow solutions : a- Developing a plug-in that could be integrated to the existing authentication system. This plug-in will interact with the OTP-Server for otp validation. b- Installing a radius server in front of the existing IT system. This server will be configured in a way it will redirect first factor authentication requests (exple : username/password) to the existing authentication system and the OTP second factor authentication to the OTP services Server hosted and give access to user only when this 2 factors are valide. I have no idea about Radius. And these are general ideas and I want someone to tell me if these solutions are possible and how to proceed. Wats is best or better to do? Is there any other solution? Waiting for your response. Thanks in advance.