Network troubleshooting with Wireshark and the command line

When an application is slow or a connection keeps dropping, teams often argue: the developers blame the network, the network team blames the application, and the vendor blames everyone else. A packet capture shows what actually happened on the wire. This course teaches you to capture traffic safely, read it with confidence and turn what you see into a clear diagnosis.

What you will learn

• Installing Wireshark and capturing on the right interface without drowning in data
• Reading the packet list, details and bytes panes
• Writing capture filters and display filters that find what matters
• Recognising normal ARP, DHCP, DNS, TCP, TLS and HTTP behaviour
• Diagnosing retransmissions, window problems, latency and resets
• Using tcpdump and tshark on servers without a graphical interface
• Working through real style cases: slow sites, failing DNS, API timeouts and Wi-Fi drops
• Capturing legally and ethically, and writing up findings for others

Practice files

Every lesson comes with sample capture files recorded in a lab, so you can follow along even if you cannot capture on your own network. You will also run safe captures of your own traffic, such as browsing a site or resolving a name.

Who it is for

Network and system administrators, developers, support engineers and security learners who know networking basics, such as IP addresses, ports and the difference between TCP and UDP, and want to troubleshoot with evidence. The course uses a current Wireshark 4 release, which is free and runs on Windows, macOS and Linux.