COMMUNICATION SYSTEM, INFORMATION PROVIDING DEVICE, PROGRAM, AND INFORMATION PROVIDING METHOD

An information providing device arranged in a first network is provided which includes: an association storage section for storing user identification information and session identification information in association with each other; a confirmation request transmitting section for transmitting, to a relay arranged in a second network, a confirmation request for confirming whether the relay has stored a connection request to the information providing device, transmitted by a communication terminal arranged in the second network; an information receiving section for receiving information included in the connection request; a terminal authentication section for determining whether authentication of the communication terminal is permitted based on the user identification information included in the connection request if the session identification information stored in the association storage section is not included in the information received by the information receiving section; a session identification information assigning section for assigning session identification information when the authentication is determined to be permitted, causing the session identification information to be stored in the association storage section; a session identification information transmitting section for transmitting the session identification information to the relay; and an information providing section for providing information to the communication terminal in response to the information received by the information receiving section if the session identification information stored in the association storage section is included in the information received by the information receiving section.