Ethernet, WLAN (Wi-Fi) and Siri Today I updated to macOS Sierra. Until now I disabled WLAN, because my Mac is connected via Ethernet (cable). However, Siri needs WLAN to determine where I am. Thus without WLAN, Siri cannot answer my questions e.g. about the weather. So I enabled it again.

Now my Mac is also connected via WLAN. Does this mean, net traffic now goes over the air though the Mac is connected via Ethernet? (I wouldn’t like that.)
No, not necessarily. The priority given by your Mac to the various connections are determined by the order of services listed in your Network settings. To view this:


Go to System Preferences > Network:




If your Ethernet connection is not listed above your Wi-Fi connection, you can change the order as follows:


Click on the Cog/Gear icon (on the right of the minus '-' sign at bottom left)
Select Set Service Order...
In the Service Order window that appears, click and drag the Ethernet connection so it is at the top (or at least above your Wi-Fi connection)
Click OK
Exit System Preferences


As an aside, Siri just needs to be able to access the Internet to work, it doesn't specifically require a WLAN connection to work. If you can't get it to work on Ethernet, then perhaps you should post another question about that.