Connect Sydney 5090

Connect Sydney 5090

Purpose

Use the SSH alias Sydney_5090 for remote access to the host at 100.120.95.16 as junjiezhao. Prefer the alias over repeating raw SSH options.

Expected SSH Config

The expected ~/.ssh/config entry is:

Host Sydney_5090
    HostName 100.120.95.16
    User junjiezhao
    IdentityFile ~/.ssh/id_ed25519
    IdentitiesOnly yes
    ServerAliveInterval 20
    ServerAliveCountMax 3
    TCPKeepAlive yes
    ControlMaster auto
    ControlPersist 10m
    ControlPath ~/.ssh/cm-%C

Before connecting, verify the alias exists if the local SSH setup is uncertain:

ssh -G Sydney_5090 | rg '^(hostname|user|identityfile|identitiesonly|controlpath) '

If the alias is missing and the task requires using this host, add or update only the Host Sydney_5090 block in ~/.ssh/config. Preserve other SSH config entries.

Connection Commands

Use these commands:

ssh Sydney_5090
ssh Sydney_5090 'hostname && whoami && uptime'
scp local-file Sydney_5090:/remote/path/
rsync -av local-dir/ Sydney_5090:/remote/path/

Prefer non-interactive ssh Sydney_5090 '<command>' for checks and small remote tasks. Use an interactive shell only when the user asks for one or when a task genuinely requires it.

Troubleshooting

• If authentication fails, check that ~/.ssh/id_ed25519 exists and is not world-readable.
• If the host is unreachable, remember that 100.120.95.16 is in the private 100.64.0.0/10 range; check the relevant overlay network or VPN before changing SSH options.
• If a multiplexed connection is stale, try ssh -O check Sydney_5090 and then ssh -O exit Sydney_5090 before removing control socket files manually.
• Use ssh -vvv Sydney_5090 only for diagnosis, and redact sensitive paths or environment details before reporting output.

Safety Rules

• Never print or inspect private key contents.
• Do not disable host key checking to bypass warnings.
• Do not modify known_hosts, delete SSH control sockets, or change key permissions unless the task requires it and the action is clearly scoped.
• Ask for explicit confirmation before destructive or long-running remote commands.