| 摘要 |
PROBLEM TO BE SOLVED: To improve accuracy of user confirmation without impairing user-friendliness.SOLUTION: When an authentication request packet is received from a terminal and authentication based on a user ID and password succeeds (yes in 34), user agent (UA) information is extracted from an HTTP header of a packet, and an access source IP address is also extracted (36). The user is authenticated by verifying the IP address and UA information extracted from the authentication request packet previously received by the same user with use history information registered with maximum two pairs (38, 44, 46). When pairs of the extracted new IP address and UA information and the respectively corresponding IP address and UA information are registered in the use history information, it is determined as success in authentication, and the new IP address and UA information are overwritten and registered in the use history information (52, 54, 60, 62). |
