Write maintainable SSH config

The alias status-vps declares host name, user, identity, and identities-only behavior without affecting other hosts. This is a small part of a safe operator path from a local machine to a disposable Ubuntu server, including file transfer, tunnels, automation, and recovery, but the boundary it creates affects everything that follows.

Client configuration reduces typing, but broad wildcard rules can silently select the wrong user, key, proxy, or forwarding behavior. The useful target is not encyclopedic coverage. Make one deliberate choice, observe its consequences, and know which requirement would make you revise it.

Watch for one shortcut in particular: trying to put sensitive or host-specific options under an unrestricted wildcard. It makes later failures harder to locate. Instead, create specific host blocks, inspect effective configuration, and keep defaults conservative. Prefer an implementation you can explain from the outside before optimizing it.

Keep the wider goal in view: Create a maintainable client identity setup without copying private keys or making authentication implicit. A short observation with concrete evidence is more useful than a confident sentence with no reproduction path.

Build two aliases for the same server with different safe purposes and compare their effective configuration. Hand the result to someone else and see whether the behavior is clear without an oral explanation.