Network system, machine allocation device and machine allocation method

A network system coupled to a first physical network and providing a service to a device coupled to the first physical network,

• the network system comprising a second physical network coupling to one or more physical computers;
• the network system, for each user using the device, being configured to:
• specify a first virtual network for the user, the first virtual network being configured on the first physical network;
• specify one or more virtual machines generated on the physical computer, the virtual machine running an application providing the service to the device;
• specify a second virtual network for the user on the second physical network, the second virtual network being coupled to the one or more virtual machines specified;
• and
• generate a private network for the user, by determining an association between the first virtual network, the second virtual network and the virtual machine.