seque.md

sequenceDiagram
  participant C as Client (10.0.0.10:54321)
  participant S as Server (10.0.0.80:80)

  C->>S: SYN
  S->>C: SYN/ACK
  C->>S: ACK
Note over C,S: TCP 3-way handshake established

  C->>S: POST /login HTTP/1.1
Note right of C: Host: demo.local User-Agent: LabBrowser/1.0 Content-Type: application/x-www-form-urlencoded Content-Length: 30  Connection: keep-alive  Body: username=alice password=lab123
  S-->>C: HTTP/1.1 200 OK (Set-Cookie: sessionid=ABC123XYZ)   
  Note left of S: Content-Type: text/html charset=UTF-8
  Note left of S: Set-Cookie: sessionid=ABC123XYZ HttpOnly
  Note left of S: Content-Length: 39
  Note left of S: Body: "Welcome alice"
  Note over C,S: Keep-Alive (HTTP/1.1)

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