Wireshark: capturing on the right interface, simple display filters and saving a .pcapng file

Wireshark is a free, widely used packet analyzer. It captures frames passing through a network interface and decodes them layer by layer, so you can see exactly what devices are sending. Support technicians use it to confirm whether traffic is leaving a computer, whether a server answers, and where a conversation fails. Capture only on networks where you are authorized, since packets can contain sensitive data.