nas1 ==> localhost nas2 ==> 200.300.xxx.1 sqlippool UserName NASIPAddress CallingStationID pool_key user1 127.0.0.1 111.111.111.22 5 user2 127.0.0.1 222.222.222.22 4 user3 127.0.0.1 333.333.333.22 7 user4 login ........... user3 NASIPAddress CallingStationID => blank user3 pool_key ==> 0 user4 pool_key ==> 7 sqlippool UserName NASIPAddress CallingStationID pool_key user1 127.0.0.1 111.111.111.22 5 user2 127.0.0.1 222.222.222.22 4 user3 0 user4 127.0.0.1 444.444.444.22 7