Pick a tool
Each tool runs entirely in your browser. Suggested order: start with the protocol map, then follow a packet, compare peer layers, and finish with NAT and proxies.
01L1–L7
Protocol Browser
A map of network protocols, sorted by OSI or TCP/IP layer. Hover a protocol to see what it runs on; click for details, known attacks and safer alternatives.
/layers_n_protocols/Open →02L1–L7
Encapsulation Simulator
Follow an HTTP, HTTPS or DNS request step by step through a switch, a NAT router and the Internet, and watch every header being added and removed.
/encapsulator/Open →03peer ⇄ peer
PeerScope
Every layer talks to its peer. See what client, network and server exchange and can read at each layer, with HTTP, HTTPS, DNS and SSH.
/peerscope/Open →04L2–L4 · L7
ProxyNATor
Packet-by-packet simulator for routing, SNAT, PAT, port forwarding and HTTP proxies, with ready-made demonstrations, exercises and PDF handouts.
/proxynator/Open →