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Protocols6 min read

HTTP Proxy Headers Explained

Via, X-Forwarded-For, Proxy-Connection, and Proxy-Authorization headers — what they leak and how targets use them.

Via, X-Forwarded-For, Proxy-Connection, and Proxy-Authorization headers — what they leak and how targets use them.

Common headers

  • Via: proxy identification
  • X-Forwarded-For: client chain
  • Proxy-Authorization: credentials
  • Proxy-Connection: keep-alive hints

Related: anonymity levels.

Detection impact

Targets fingerprint header order and presence. Elite pools minimize revealing headers.

Client behavior

Libraries differ in which headers they send. Test with your actual HTTP client, not just curl.

Related: curl proxy config.

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