Validates a second sshd (own port/config/host-key/AuthorizedKeysFile/unit) as
Felhom's OOB entry point, coexisting with the customer's stock sshd on :22:
robust port probe-and-claim (skip/idempotent/loud-exhaustion), four-axis
coexistence independence, tunnel-scoped nft, reload-gate robustness, operator
identity isolated via AuthorizedKeysFile location, clean uninstall.
#1 TASK constraint (caught live): a second sshd unit must NEVER declare
RuntimeDirectory=sshd — it removes the SHARED /run/sshd privsep dir on stop and
takes the stock sshd down (LAN SSH lockout; recovered via PVE console + mkdir
/run/sshd). Use a tmpfiles.d entry instead. All spike artifacts removed; baseline
re-verified.
Docs-only; no code/hub/agent/manifest change.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6
