SSH Doctor

Use when SSH connects then closes before auth, Remote Login seems advertised but unusable, or local/remote Mac SSH needs diagnosis.

Rules

• Do not print secrets, tokens, full env, or broad secret grep output.
• Validate locally first: loopback failure means server-side sshd/launchd/config; loopback success plus remote failure means network/firewall/filter/listen path.
• Report suspicious config lines before changing /etc/ssh/sshd_config.
• Prefer non-interactive SSH:

ssh -o RequestTTY=no -o RemoteCommand=none HOST 'hostname; id -un'

Baseline