Visual Learning · 03 · Live

HTTP Request & Response

GET /index.html out; 200 OK + HTML back — request/response on the wire.

CYNARKS

Teaching simulation · not live capture

HTTP Request & Response

Lab origin only.

Real world · APIs and websites speak HTTP: method + path + headers out; status + headers + body back — the language of every browser.

Attack · Tampered headers or smuggled requests abuse HTTP parsing (covered in web-security modules).

Defense · Strict parsers, Host validation, and HTTPS-only reduce request abuse.

  • Control · Validate Host and method allow-lists
  • Control · Never trust client-supplied Content-Length alone in proxies
  • Control · Prefer HTTP/2+ with modern stacks; keep cleartext HTTP off production

1. GET

Browser

user
GET

GET /index.html

Web App

origin
Browser sends GET with Host and Accept headers.

GET /index.html

  • #1 client → server GET GET /index.html

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