Generate Access-Challenge from radius server

Hi, I want to generate Access-Challenge from radius server on Access-Request packet while using CHAP. But server is not generating challenge packet for any of the Access-request, i am using radclient. Please tell the configurations to be done on the radius server as well as attributes to be sent in Access-Request through radclient , so that radius server can send Access-Challenge packet while replying Access-Request packet. i am executing following command from radclient. *radclient -x server-ip-address auth secretkey* *User-Name = "testuser"* *CHAP-Password = "testing" * *ctrl+d* Thanks, Arpit