One Time Password Systems are quite interesting for Server/Client connections. As each authentication operation requires a new password. Therefor a Challenge/Response mechanism has to be implemented, with all it pro and cons.
One time passwords (OTP) are a very safe way to implement two factor authentication. So I looked for a easy possibililty to use OTP in FreeRADIUS. I also wanted to use smart phone based OTP generators, since everybody has such a device nowadays. Finally I found a very nice combination of DroidOTP, motp and FreeRADIUS to do the job.