Can someone explain what the ethernet or wi-fi setting does under the "other wi-fi devices"......
If your Mac is connected to your router using a wireless connection, then there should be a check mark next to Wi-Fi when you check AirPort Utility / other Wi-Fi devices.
Likewise, if your Mac is connected to your router using a wired Ethernet cable connection....and....you have turned off Wi-Fi on the Mac using the Wi-Fi menu at the top of the Mac's screen.....then there should be a check mark next to Ethernet when you check using AirPort Utility / other Wi-Fi devices.
In other words, this setting simply tells you whether the Mac is connecting to your network using a Wi-Fi or wired connection at the time.
If for some reason that you have both Ethernet and Wi-Fi enabled on your Mac, then the check mark will appear under the active connection at the time. If you want to switch from one connection type to the other, simply click on the other connection option.
and under "network interfaces"?
Here, I am assuming that you have opened System Preferences.....(the gear icon on the dock)....and that you have then opened Network.
The current connection that the Mac is using to connect to your network.....either Wi-Fi or Ethernet......will appear at the top of the connection list. If both Wi-Fi and Ethernet are active at the time, then the Wi-Fi connection will usually appear at the top of the list.
This would indicate that your Mac will connect to the Wi-Fi connection first when it has the option of connecting either using Wi-Fi or Ethernet.
If you want your Mac to connect to Ethernet first when it has the option of connecting using either Wi-Fi or Ethernet, you will need to click on the small gear icon at the bottom of the connection list, then click on Set Service Order, and drag the Ethernet connection to the top of the list.
