When my Mac is connected to both ethernet and Wi-Fi, which does it use for internet?

[iMore Question]

I have a really nice Mac Pro. At the office I work at, the Wi-Fi can get a bit dodgy, so I have the machine plugged into an ethernet cable.

However, we also have Sonos music here which requires a Wi-Fi connection for me to able to use the Sonos app to control the music. This forces me to turn on the Wi-Fi on my Mac Pro.

With the Wi-Fi on, Sonos works. Awesome! However, I'm confused as to what is now being used for Internet while browsing the web, downloading things, Dropbox syncing, etc. I have a feeling it's the Wi-Fi.

Can anybody clarify this? If Wi-Fi is getting used for everything once turned on, is there any way to specify for apps which data connection to use? In reality, I only want Wi-Fi for Sonos and Ethernet for everything else.

Thanks!

 

[Just_Me_D]

Probably whichever is connected first...

 

[Peter Cohen]

You can specify the order in which your Mac Pro will use its network interfaces: Go to the Network system preference, click on the gearbox below the sidebar listing what interfaces are being used, and select "Set Service Order."

There's no easy way that I'm aware of, anyway, to set priority for specific network interfaces for specific apps.