Hi Alan, Thanks for the response, its no problem starting fresh. FreeRADIUS reset back to default... then... Created file /etc/raddb/policy.d/policy.conf contents the same as Wiki. For 'raddb/modules/file' you say 'put that file into raddb/mods-enabled/authorized_macs' So, created file raddb/mods-enabled/authorized_macs and it has contents of wiki module/file. Created raddb/authorized_macs Started 'radiusd -X'. No errors. Now for the raddb/sites-available/default. Edited the file and added the section from the Wiki after the existing 'preprocess' so it now looks like this: -- snippet starting at line 271 in 'default' -- preprocess # if cleaning up the Calling-Station-Id... rewrite_calling_station_id # now check against the authorized_macs file authorized_macs if (!ok) { reject } else { # accept update control { Auth-Type := Accept } } # If you intend to use CUI and you require that the Operator-Name # be set for CUI generation and you want to generate CUI also # for your local clients then uncomment the operator-name # below and set the operator-name for your clients in clients.conf # operator-name -- end snippet -- Started 'radiusd -X'. No errors. That looks OK at the moment, so I hope this is correct and proves useful to anyone else who is experiencing the same issue. Thanks for your help, I'll be continuing this lab next week. Regards, Ben