What are the best practices for using Wireshark to monitor networks?

1 Choose the right capture interface

Before you start capturing network traffic, you need to select the appropriate interface on your computer or device. You can use Wireshark to list the available interfaces and their statistics, such as packets per second, bytes per second, and link layer type. You should choose the interface that matches the network segment or layer that you want to analyze. For example, if you want to monitor the traffic between your computer and the internet, you should select the interface that connects to your router or modem. If you want to monitor the traffic on a local area network (LAN), you should select the interface that connects to the switch or hub.

2 Apply capture filters and display filters

Wireshark can capture a lot of data, which can be overwhelming and time-consuming to analyze. To reduce the amount of data and focus on the relevant information, you should use capture filters and display filters. Capture filters are applied before the capture starts and limit the packets that are recorded by Wireshark. Display filters are applied after the capture is done and filter the packets that are displayed on the screen. You can use capture filters and display filters to specify criteria such as IP addresses, ports, protocols, or keywords. For example, if you want to capture only the traffic related to HTTP, you can use a capture filter like tcp port 80 or a display filter like http.

4 Analyze packet details and follow streams

Wireshark provides a lot of information about each packet that is captured, such as the source and destination addresses, the protocol headers, the payload data, and the expert information. You can use Wireshark to examine the packet details and follow the streams of communication between different hosts or applications. You can use packet details and follow streams to understand how protocols work, how data is transferred, how sessions are established and terminated, and how errors are handled. For example, if you want to analyze how a web browser communicates with a web server, you can follow the TCP or HTTP stream and see the request and response messages, the cookies, the headers, and the content.

5 Use statistics and graphs

Wireshark offers various statistics and graphs that can help you measure and visualize the network traffic. You can use statistics and graphs to get an overview of the network activity, the protocols, the endpoints, the conversations, the throughput, the round-trip time, the packet size, and more. You can use statistics and graphs to compare and contrast different network scenarios, identify trends, bottlenecks, or outliers, and optimize network performance and security. For example, if you want to evaluate the network bandwidth usage, you can use the IO graph to see the bytes per second or packets per second over time.

Wireshark is a versatile and valuable tool for network monitoring, but it requires some skills and knowledge to use it properly. By following these best practices, you can make the most of Wireshark and improve your network analysis and troubleshooting skills.