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- The first NetMon instance checks the established connections on a numbered port (e.g. 1883). If the number of connections is greater than VALUE, it runs a SCRIPT (just a Linux 'sleep' command), which increments a heartbeat counter in register 40012. The increasing value represents a good condition.
- The second NetMon instance checks the value heartbeat counter in Channel/RTU, register 40012. If the register stops increasing, then restart the Ethernet ports.
This instance needs to run at a MONITOR Interval that is more than the interval of the first instance, to ensure the count will have increased normally.
(To restart just a single Ethernet port instead of all ports, the Instance 2 Action could be a SCRIPT, with Action Text:ifdown eth0; sleep 1; ifup eth0#(use the correct eth_ port number)
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(Note that this example could have combined the condition of ESTABLISHED ports with the Restart of Ethernet ports in a single NetMon instance. But that could cause the Ethernet network to restart even when there is a natural reconnection of the TCP socket. By using an increasing heartbeat counter in Instance 1, and configuring Instance 2 to run read the counter several times slower than Instance 1, it will avoid premature restarts of the network.)
Also note that a 3rd NetMon instance could be added, which looks at the register value of 40014 (number of times the Ethernet networking has been restarted) at an even less frequent interval. If the count is "Greater than" a certain value (or Increases >= a certain value within a monitoring interval, such as 5 minutes), the action 40012 (heartbeat counter) at a much less frequent interval, for instance 10 minutes or an hour. If the heartbeat counter doesn't increase more than a small amount, this indicates that the Ethernet restarts (NetMon instance 2) aren't working, and the Action could be to reboot the RediGate , as a more drastic effort to recover communication, if possible.
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