How To Capture and Inspect Network Packets in Wireshark Tool

Wireshark is a free and open-source network protocol analyzer that allows users to capture and inspect network traffic in great detail. This powerful tool can help network administrators and security professionals troubleshoot network issues, analyze network performance, and discover security threats.

Getting Started with Wireshark

Wireshark can be easily downloaded and installed on Windows, Linux, and macOS systems. Some key things to know when getting started:

  • Wireshark requires administrator or root privileges to capture network traffic
  • It captures traffic from Ethernet, Wi-Fi, and other network interfaces on your system
  • Captures can be saved to disk in .pcap format for later analysis

Capturing Live Network Traffic

To capture live network traffic with Wireshark:

  1. Select the network interface you want to capture from (e.g. Ethernet, Wi-Fi)
  2. Click Capture > Options to select capture filters, file size limits, etc.
  3. Click Start to begin the packet capture
  4. Generate network traffic by browsing websites, transferring files, etc
  5. Click Stop when you want to end the capture

The capture will contain all network traffic seen on the selected interface while it was running.

Capture Filters

Capture filters allow you to select which protocols and traffic to capture. For example, to only capture HTTP traffic on port 80:

port 80 or port 8080

Capture filters use the same syntax as tcpdump.

Inspecting Captured Packets

Once you’ve captured some packets, Wireshark provides powerful ways to inspect and analyze them:

Summary Pane

The top summary pane displays a one-line summary for each packet, including the packet number, timestamp, source/destination addresses, protocol, length, etc. This provides a high-level overview of the capture.

Packet Details Pane

The packet details pane shows the full contents of the currently selected packet, broken down by protocol layer (Ethernet, IP, TCP, HTTP, etc.) You can expand each protocol section to dig into the packet.

Packet Bytes Pane

The packet bytes pane shows a hex dump of the raw packet bytes. This allows you to examine the packet bits.

Follow TCP Streams

This feature reassembles entire TCP conversations and displays the full application-layer data stream in an easy to read format. Useful for examining web, chat, and other TCP-based traffic.

Advanced Wireshark Features

Wireshark offers many advanced features for more effective packet analysis:

  • Display filters – Create complex filters to selectively display packets of interest
  • I/O graphs – Visualize traffic patterns over time
  • Protocol hierarchy statistics – View bandwidth usage by protocol
  • Expert info – Warnings identify potential problems or unusual behavior
  • Coloring rules – Visually highlight important packets through coloring

And much more! The extensive documentation covers all features in depth.

Use Cases

Common use cases for Wireshark include:

  • Troubleshooting network and application performance issues
  • Analyzing security threats like malware and intrusions
  • Reverse engineering proprietary protocols
  • Debugging network protocol implementations
  • Learning how protocols work by examination

From hobbyists to security experts, Wireshark provides a rich set of capabilities for working with network traffic. Its free open source license and cross-platform support have made it the tool of choice for packet analysis.