SSH & Remote Administration

Stop guessing which SSH key is actually getting you into that box

🧩 The Challenge

Dealing with a dozen different SSH keys for various clients and servers is a recipe for disaster, especially when you run into that annoying permission denied error. You’ve wasted twenty minutes checking the remote auth logs only to realize you were accidentally offering your personal GitHub key instead of the company one.

💡 The Fix

Tell your SSH client exactly which identity file to use for a specific host by pinning it in your config file. It clears up the confusion instantly and saves your login attempts from being throttled.

Host production-web-01
HostName 10.0.4.22
IdentityFile ~/.ssh/id_ed25519_company
IdentitiesOnly yes

⚙️ Why It Works

Setting IdentitiesOnly to yes forces SSH to ignore your default agent keys and use only the file you specified. That little flag is the difference between a successful login and hitting a rate limit on your own infrastructure.

🚀 Pro-Tip: Add the -v flag to your SSH command once if you’re ever truly stuck; it’ll dump the exact order of keys it’s trying so you can see where it’s failing.

Linux Tips & Tricks | © ngelinux.com | 9/9/2026