Setting up Wireshark

As a tool for network engineers, Wireshark is immeasurably useful, and I strongly encourage you to familiarize yourself with its features and start to think about how you could leverage it in your own development tasks. For now, though, we'll be using its most basic packet sniffing functionality to examine every packet that comes through our open internet connection. So, once Wireshark is installed, simply open it up and select your Ethernet connection as your target for packet sniffing, as seen in the following screenshot:

When you open it on your own machine, take a second to watch the graph growing out to the right of the traffic source. This actually provides a quick view of the relative activity on the given source over time. Once your primary internet source is selected, start capturing by clicking the capture button on the top-left of the toolbar, or simply double-clicking the desired source. Allow the tool to capture traffic for a few minutes just to get a good range of sample data and then start exploring on your own. If you've never used a tool such as Wireshark or Fiddler before, you'll likely be surprised by how much chatter is actually happening, even with no input from you directly.

With the tool installed and running, let's take a look at some of the features of a packet specified by our definition and see how it translates to real-world implementations.