Windows networking: how does Windows decide between WiFi and an Ethernet cable connection?

The question came up in a recent software training class, so I thought I'd post a quick blog post about it. The question is, "If I have both my WiFi enabled and plug in an Ethernet cable, which connection does my computer use?"

The short answer is that usually, the Ethernet connection takes precedence, as it is "more robust". However, this is often coincidental, and does not always work this way. Instead, Windows deals multiple network connections based on pre-set preference, which can also be easily controlled by the user (or an administrator).

To see (and possibly adjust) the connection usage preference (priority), open up the Network and Sharing Center, and the go to the adapter settings page. Next, press the Alt key on the keyboard to open the hidden menubar, and then choose the Advanced menu. From the menu, choose Advanced Settings. Next, you will see a similarly named dialog box on the screen.

In this dialog box, you can specify the relative order of different network connections, for instance your WiFi and Ethernet (RJ45) connection. By changing the order of the connections, you can control which of the connections is used first. The one at the top of the list is the one that has priority.

Keywords: WiFi and Ethernet cable priority.