Message Authenticator attribute is missing

Hi, i am testing one basic authentication scenario using freeradius. The client is getting successfully authenticated but i am not seeing any "Message-Authenticator" attribute in the Access-Accept or Access-Reject packets. Does server not send "Message-Authenticator" attribute by default? How we can enable freeradius server to send "Message-Authenticator" attribute for all response packets? Thanks & Regards, Amit