Protocol Explorer is an interactive network protocol visualizer. Pick a protocol, press play, and the packets move between a client, a router, a DNS resolver and a server while a capture table stays in sync with the animation. Click any packet and Protocol Explorer decodes its headers byte by byte — Ethernet, IPv4, TCP, TLS — so the field you read about in a textbook is the field you can point at on screen.
The library covers 33 protocols across four categories: core transport, application, security, and the plumbing that holds networks together. Four of them — HTTP, HTTPS, TCP and UDP — are free, including the overview and the first three steps of each exchange. Everything else belongs to Protocol Explorer Pro, a one-time $4.99 pass.
Play, pause, step forward or replay at half or double speed. Every lesson is four to seven events long, and each event explains one message.
The inspector splits a frame into its protocol layers, labels every field, and marks which bytes the lesson cannot show because they are encrypted or random.
Network view shows who is talking to whom. Sequence view stacks the participants and orders the messages, which is the layout you want before an interview.
Protocol Explorer remembers which protocols you finished and resumes the one you were on, on every device you sign in to.
Students meeting TCP/IP for the first time, engineers preparing for interviews, backend developers who want to stop guessing what a timeout means, and instructors who need a diagram that actually moves. Protocol Explorer is a teaching model, not a packet analyser: use it to build the mental picture, then go read the RFC or open a real capture.