Re:

Frost, Benjamin M. wrote:

...I was wondering if it’s possible to initiate a challenge/response in order to prompt for another piece of data. Example. Domain Username / Domain password and then come back with a request for a one-time password. I tried to return 11; even though it’s not listed as a viable return value. Any idea on if this is possible?

It's not. To send an Access-Challenge, you will need to write C code. See rlm_example. Alan DeKok.