I have two IX20's that will be connected via IPSec. I need one of the IX20s to act as a modbus server for the LAN devices attached to the other IX20. I am using the serial port for the local communications to the modbus device. I have the VPN set up and working, however I've noticed that as soon as I disconnect the ethernet from the ETH2 port, the interface goes down and the device is no longer reachable at that address (which I am using as a modbus gateway).
Is there a way to reserve a dummy address that's reachable whether or not the ETH2 interface is up? I have played around with a secondary loopback address, however whenever it's enabled, I lose access to the device via the interface/SSH and have to restore the configuration.
Maybe there's an easier way to do this? I can post some screenshots of my config if it helps.
Thanks in advance.