NetCheck uses ICMP packets to monitor specified devices on an IP network. NetCheck allows the user to schedule when (at what interval) to check the list of devices and applications. Instead of forcing the user to keep the NetCheck GUI application running to start the check at the specified times, NetCheck adds a user cron entry to do this and this cron entry will point to the "hound" binary executable with a path of /Applications/NetCheck/ hound. The hound process is what does all the ICMP device checking and the Application checking.
When the hound process is called by cron, the hound process reads the records from the devices table and starts on the first device/record. The hound process first checks to see if the device is in disabled state. If disabled, the hound process ignores the Disabled device entry and moves to the next device. If the device record is in Enabled state, the hound process creates another copy of itself (also called hound) to do the work for the first device. This new hound (child process) then uses the Ping Attempts and Timeout values and starts sending ICMP pings to check for UP status and perform email alert notification and logging if DOWN status is detected. You can also configure how often the hound process will be called by clicking the "Set Cron Settings" button.