Hi Alan, Many apologies for not responding to your response to my issue. It was excellent that you responded so quickly. I have resolved the issue and mailing here so it will be available if anyone else has the same problem. For some reason, and unsure why, after following Microsofts installation process for the unix and ms - odbc drivers and then following the freeradius instructions for odbc installation it looked like the drivers were not present when running radius -X (even though unixodbc and msodbc were there afetr confirming). The way the issue was resolved was by completing the following: yum list freeradius-* We get the following appearing in the list: freeradius-unixODBC.x86_64 yum install freeradius-unixODBC.x86_64 I restarted mssql-server as a precaution and then ran radiusd -X and everything worked. I completed a radtest and got successful accept packet returned. Thank you for you help Alan. Very much appreciated. I do have another question but will ask that in a separate mail. Thank you again.