A relay program, communication processing program, and firewall system capable of simplifying security management in a firewall. In a firewall, only an aggregation port that is an aggregation of one or a plurality of ports to be allowed to pass through is set to be allowed. When a communication source client makes a connection with a target connection request destination connected to an internal network, the communication source client issues connection request information specifying the target connection request destination with its destination set to the aggregation port. In a relay server, a connection request information acquisition unit reads the connection request information that passed through the firewall and is input via the aggregation port. A relay unit changes the destination to the target connection request destination based on the connection request information and sends the connection request information to the target connection request destination to thereby make a connection request, and also sends connection result information obtained from the target connection request destination to the communication source client.