generating ACCESS-CHALLENGE from radius server

[Sudarshan Soma]

Hi ,
I am planning to simulate ACCESS-CHALLENGE to authenticate the client
which i plan to add it in pam-radius module (pam_radius-1.3.17) with
out using radius server.  Iam still reading the docs, incase if
someone helps me with the following queries, it would be really
helpful.

I learned that the rlm_otp has the implementation of the same. Could
anyone please let me know these:
- any radius client which lets radius server to ask for ACCESS-CHALLENGE
       -- (echo 'User-Name="userX"'; echo
'CHAP-Password="secretpass"') | /usr/local/bin/radclient -x
192.168.11.94:1812 auth testing123 is not helping
-  how do i test rlm_otp module, any radius client program..

Regards,
Pavan