An information processing system includes: an SNS server apparatus configured to be connected to a network and store one or more messages submitted to an SNS from a terminal apparatus; and a client apparatus configured to be connected to the network via a firewall and capable of communicating with the SNS server apparatus, the client apparatus being configured to receive, from the SNS server apparatus, one or more messages submitted to a channel, to which the client apparatus logs in, of the SNS, extract, from the one or more messages, a message including a control command to the client apparatus, and execute processing in accordance with the control command.