User authentication system using IP address and method thereof

The present invention relates to a user authentication system and method using an IP address checking. The present invention is to build a list of valid IP addresses from your access logs, and to include a list of the valid IP address to the session cookie, dynamically performs in environments where IP addresses change seamless web services and user authentication. In addition, the present invention is important in the URL used when the IP address changes, by updating the valid IP address list according to the result of the request to re-login, and the re-login performs user authentication adaptively. Further, by providing the selection of the effective use of IP address list and the security level of the user and provides a high convenience. Login, user authentication, session cookies, IP addresses,