A Network Integrity Ping is a third network entity, the other ones being the main and backup servers, used to determine if a network is active. If neither the integrity address nor the backup server can be reached, the main server assumes that its network interface is not working and immediately terminates Domain's execution. If the server in Standby mode can successfully reach the integrity address but not the server in Hot mode (main), it assumes that the Hot server is not working and takes over Domain's execution.