Wireshark

Wireshark is one of the best-known open-source tools for examining network traffic at packet level. Rather than acting as a traditional prevention product, it gives engineers and security professionals a detailed view of what is moving across a network and how protocols behave. Analysts use it for troubleshooting connectivity problems, validating application communications, investigating suspicious traffic and learning how network protocols operate. Its graphical interface supports deep inspection while TShark provides command-line access for automated and scripted workflows. Because the project is open source, Wireshark is widely used in education, research, engineering and security operations. It can also become an important investigation aid when a team needs evidence from actual network traffic instead of relying only on summarized logs. The project’s broad protocol support makes it useful across complex environments where understanding traffic behavior is essential. Its combination of detailed visibility, protocol support and extensibility keeps it useful for both day-to-day diagnostics and deeper security investigations.