Intermediary
An intermediary acts between an HTTP client and server while forwarding, transforming, caching, or tunneling traffic.
- intermediaries
- proxies
- messages
Definition
An intermediary is an HTTP participant between a client and server. Proxies, gateways, and tunnels have different roles, but each can affect the path between the endpoints.
user agent -> forward proxy -> CDN gateway -> origin server
Expected result: each HTTP-aware hop can contribute observable timing or message behavior. A tunnel instead relays bytes without acting as an HTTP message recipient after the tunnel is established.
Why it matters
An unexpected field, cache result, redirect, or protocol version might come from an intermediary rather than the application origin. Diagnosis should identify which hop produced the evidence.