TCP Handshake Visualizer

TCP State Machine

Client

Server

Sequence Numbers

Client SEQ—

Client ACK—

Server SEQ—

Server ACK—

Sliding Window

0——

RTT:— RTO:—

Event Log

Interactive Protocol Diagram

Watch the TCP 3-way handshake, data transfer, and connection teardown in real time
Choose a scenario: normal flow, packet loss, fast retransmit, RST, or simultaneous open
Use Step to advance one event at a time, or Play for auto-play
Adjust speed, packet loss probability, and window size in the controls above
The right panel shows the TCP state machine, sequence numbers, and event log

Click anywhere to start