User-chosen fully-open registration on tuwunel (no CAPTCHA support; browser
challenges break native clients). Bot defense is layered instead:
- Traefik rate-limit Middleware on a path-scoped /register ingress carve-out,
keyed on request Host (GLOBAL /register cap) not source IP — the host is
reachable via both Cloudflare-IPv4 (CF-Connecting-IP) and IPv6-direct (HE
tunnel, no CF header), so a per-source key let IPv6 bots bypass. 10/min,
burst 20, per replica; CrowdSec is the hard backstop on both paths.
- Loki ruler rule MatrixNewUserRegistered -> lane=security -> existing
#security Slack receiver (matches "registered on this server", never the
rejection line). tuwunel's admin bot also posts signups to the admin room.
Dropped the REGISTRATION_TOKEN env (secret/matrix + ESO kept for revert).
Applied via scripts/tg (matrix tier-1 + targeted monitoring configmap), so
[ci skip] to avoid CI full-applying monitoring (unrelated grafana-acl drift).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
6504911a77