Hollowport Lab / 404 Not Found

h1-status-404

404 Not Found

Responds 404 with a short known text body and a deliberately duplicated response header (two X-Lab-Note lines with different values, in this order).

CLASS 2 — proves status / body / header semantics only. Does not prove origin transport, ALPN, or HTTP/2 multiplexing. This request terminates at a CDN edge, not at an origin server the Lab controls.

Run this test

Start capture, then open the test URL once.

https://hollowport.hevexa.net/lab/api/h1-status-404

What the server actually does

factvalue
status404
Content-Typetext/plain; charset=utf-8
Cache-Controlno-store
X-Lab-Testh1-status-404
X-Lab-Notefirst
X-Lab-Notesecond

Response body, verbatim:

Not found. This is the expected result for this test.

duplicatedHeader: "X-Lab-Note appears twice, values 'first' then 'second'"

About intermediaries. This request also passes through Cloudflare's edge, which adds headers of its own — cf-ray, server: cloudflare, sometimes cf-cache-status. Those belong to the intermediary, not the origin. Seeing them in your observer's capture is expected; they are not a mismatch against the ground truth above. The Lab is teaching three separate things: what the authoritative server did, what your observer actually saw, and what an intermediary added or changed along the way.

Classify what your observer showed

For each fact above, pick the category that matches what your traffic tool actually displayed. This stays on your device — nothing is submitted.

Captured & represented — The observer got this right — captured, retained, and shown correctly.
Captured, not shown — The observer has the data but exposes no field or view for it.
Partial / lossy — Present but incomplete — e.g. a body kept only up to a cap, headers reconstructed rather than verbatim.
Not observed — Nothing in the observer's evidence corresponds to this.
Mismatch — The observer's value contradicts what the server actually did.
Unknown — Not enough visible in the observer to decide either way.

Worth noting

  • Some observers merge duplicate response headers into one comma-joined value, or keep only the last — whether both X-Lab-Note lines survive verbatim, and in order, is exactly the kind of thing to check here.

The ground truth above is what the server does, independent of any observer. If your tool showed less than this, that is a finding — not a problem with the test.