Client-server system, server access authentication method, memory medium stores server-access authentication programs, and issuance device which issues the memory medium contents

A client-server system in which clients and servers are interconnected via a network, wherein

• each of said clients comprise:
• a read-out device for reading out data from a memory medium;
• a memory medium for removably connecting to the read-out device, storing a server address and memory medium identification information;
• access permission request means for connecting to the server using the server address stored in the memory medium, and transmitting the memory medium identification information to request server access permission;
• and
• each of said servers comprise:
• memory means for storing identification information for a memory medium for which server access is permitted;
• access authentication control means for comparing memory medium identification information sent from a client to the identification information stored in said memory means, and based on a result of the comparison, sends server access permission or refusal to the client;
• wherein the access permission request means is stored in the memory medium as software.