To create sqlcounter accessperiod, you need to edit /etc/raddb/mods-available/sqlcounter. sqlcounter accessperiod { sql_module_instance = sql dialect = ${modules.sql.dialect} counter_name = Max-Access-Period-Never check_name = Access-Period key = User-Name reset = never query= "SELECT TIMESTAMPDIFF(SECOND, acctstarttime, NOW()) FROM radacct WHERE UserName='%{User-Name}' ORDER BY acctstarttime LIMIT 1;" }