Resolved Internet doesn't work when two network devices are connected

[BlackPhoenix]

I recently attached a thunderbolt ethernet adaptor to my Mac, it is connect to a closed network that I am using for NFS sharing temporarily.

My internet access comes through the WiFi.

I have full internet access when I have WiFi only enabled, but as soon as I turn on the Ethernet, it stops working. It is clear why: My laptop is routing all internet requests through the ethernet connector despite the fact that that network has no external connectivity.

I have no idea how to fix this. Any thoughts?

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Silly me, all I had to do was run Network Diagnostics and explicitly set the wifi as being the internet connection device and it worked.

 

[Weaselboy]

What you may want to do to prevent this is go to the Network pane in System Prefs and click the little cog at the bottom left then select Set Service Order, and in there drag the wifi to the top of the list.