Both corrections come from the first real Phase 1 start on synlig (2026-08-12).
1. The Pangolin resource target was documented as bare `172.17.0.1:8765` with no
scheme, and the obvious guess from that is `https://` -- which cannot work.
`contrib/systemd/mempalace-serve.service` runs `serve --host 172.17.0.1
--port 8765` with no --tls-cert, so the primary speaks plaintext HTTP; TLS
terminates at Pangolin, which is the whole point of the RFC 6.2 decision.
Point a proxy at https:// and it attempts a TLS handshake against a plaintext
listener: 502 from outside, while `curl 172.17.0.1:8765/healthz` on the box
still says ok -- a confusing pair of symptoms. Now spelled `http://` with the
failure mode named, in the runbook and in the unit's comments.
2. `curl -s 127.0.0.1:8765/healthz` was documented as "expect 403". Wrong: the
real run returns empty. With a docker0-only bind nothing is listening on
loopback, so the connection is refused at TCP level before any header is sent
(%{http_code} -> 000, exit 7). The 403 is the *loopback-bind* case verified
2026-08-10 -- server on 127.0.0.1 answering a proxy-forwarded foreign Host.
Two distinct behaviours had been collapsed into one expectation in three
places (both runbooks and the unit).
Worth stating why the correction matters rather than just fixing it: refusal
is the *stronger* signal. A 403 proves only that a request was rejected; a
refused connection proves the loopback and LAN surface is not listening at
all. Someone who expected 403, saw silence, and "fixed" it by rebinding to
0.0.0.0 would have converted a correct configuration into an exposed one.
The docs now also say what to do if it hangs, or if ss shows 0.0.0.0:8765.
Joakim Persson
08e344b047