Network connection control technique, network connection technique and authentication apparatus

A computer-readable, non-transitory storage medium storing a program for causing an authentication apparatus to execute a network connection control process for controlling a network connection of a user terminal,

• wherein said network connection control process comprises:
• at a first timing when a disconnection request for a connection with a first network is received from a user terminal that is connected to said first network through a gateway and is connected through a second network to said gateway, or before said first timing, extracting an allocatable address other than a first address currently used by said user terminal from an allocated address storage device storing addresses in association with information representing whether or not the corresponding address is allocatable, wherein said gateway has an address filter table storing addresses, for which a connection to said first network is permitted, after authentication by said authentication apparatus connected to said gateway is completed;
• transmitting the extracted address as a reconnection address, which is valid for a predetermined valid period, to said user terminal;
• and
• causing said gateway to replace said first address in said address filter table of said gateway with said reconnection address at a timing of a disconnection of said user terminal from said first network, wherein said disconnection makes said gateway filter frames having said first address from said user terminal, and
• wherein, in response that a reconnection to said first network is requested after said disconnection from said user terminal by using said reconnection address within said predetermined valid period, said gateway allows said reconnection of said user terminal to said first network without passing said authentication by said authentication apparatus.