How to do it...

In Wireshark Version 2, it is very simple. When you run the software, down the main window, you will see all the interfaces with the traffic that runs over them. See the following screenshot:

The simplest way to start a simple single-interface capture is simply to double-click on the active interface (1). You can also mark the active interface and click on the capture button on the upper-left corner of the window (2), or choose Start or Ctrl + E from the Capture menu (3).