A cloud server stores information, such as a location data range, IP addresses, account names, and passwords of authorized clients. When receiving an access request from a client, the cloud server determines if location data of the client falls within the location data range and an IP address, an account name, and a password of the client matches corresponding information of any authorized client. If the location data of the client falls within the location data range and an IP address, an account name, and a password of the client match information of any authorized client, the cloud server determines that the client is an authorized client and permits the client to access the cloud server.