1. A server for establishing communication upon receipt of access from a client terminal through a network, comprising a memory protection unit for protecting data stored in a volatile memory to be protected, in the event of a power failure, said memory protection unit comprises power monitoring means for detecting a power failure supplied to said above protective memory, and switch controlling means for switching a control and power supply toward said protective memory, wherein when a failure is detected in the power supplied to said protective memory, the control toward said memory is switched to a side of said memory protection unit and said power supply is switched to a standby power before said protective memory has some damaging effect.