I think I got the syntax figured out. I just replaced:
ports:
with:
network_mode: "host"
Unfortunately it’s still doing the same thing.
Isn’t this discovery process pre-security though?
Yes, discovery is pre-security, but in the configuration that actually got you talking to something, which I can only assume was that server, it was security-related.
It was a firewall issue. Port 55105 was blocked. I am able to get the connection up now but there is one step that doesn’t work when the gateway is running on the container but works when running on a VM.
Step 1 - Create OPC Connection
Step 2 - Select OPC UA > Next
Step 3 - Enter endpoint URL - 10.0.1.156:55105
Step 4 - Select OPC Server - OPC.SimaticNET.S7OPT - opc.tcp://SNetV16:55105
Step 5 - Here the gateway in the container reports that opc.tcp://SNetV16:55105 is unreachable but the gateway in the VM does not. Is there any particular reason why the DNS resolution isn’t working in the container setup?
Note: the connection from the container will still work if I continue and use a substitute URL. I’m just curious to understand the issue with the DNS resolution failing.
I’ve never seen Linux be able to resolve a Windows host by machine name unless you are actually running a DNS server and have it all configured. It works Windows to Windows by maybe NetBIOS or something like that, not sure how they do dynamic discovery of other Windows hosts.
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