Home/Support/Support Forum/IX20 modbus gateway available when ETH2 down?
Welcome to Digi Forum, where you can ask questions and receive answers from other members of the community.

IX20 modbus gateway available when ETH2 down?

0 votes
Hi there,

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.
asked Sep 7 in Modbus and Industrial Automation by dgici New to the Community (1 point)

Please log in or register to answer this question.

1 Answer

0 votes
Best answer
You need to follow this document here:


Basically you need to create a /32 loopback interface for the IP address of the ETH interface and then set custom network descriptors in your IPsec config.

It is stupid but it is how it is and will work fine once done.

Nicholas Wilson
Your IoT
answered Sep 8 by NicholasYourIoT Seasoned Professional (194 points)
selected Sep 8 by dgici