adding a nas via dialupadmin

Hello while adding a NAS thru dialupadmin i noticed that the changes dont take effect unless the freeradius process is restarted is this intended? or is something wrong with my config I.E. i added 192.168.0.1 / as a NAS but when i tried to authenticate with the nas , the debug showed it being as unreconized.. I stoped and restarted freeradius and then that nas was able to authenticate. Freeradius 1.02-4 (debian stable version) Thanks. Nick.