Introduction

A protocol

• To remotely connect to another computer/server safely.
• Encrypts the connection → nobody can eavesdrop.
  • Secure Git operations (clone / push / pull)
• Commonly used to log in to Linux servers from your laptop.

Login

Normal login:

ssh username@server_ip

• Then will be asked for password
• Once connected, can run commands on the VPS as if you were sitting there

SSH Keys (Password-less Login)

Instead of typing password every time, we use SSH keys.

1. Generate SSH key on your local machine:

   ssh-keygen -t ed25519 -f deploy_key
   # ssh-keygen    : cmd to generate a new SSH key pair
   #	-t ed25519    : modern type of SSH key algorithm
   #	-f deploy_key : custom file name, to save the key in local
   

2. Get two files on local:

   1. deploy_key → private key, keep secret! 🔒 (as identity)
   2. deploy_key.pub → public key, share to server 🌐 (to verify u)

   C:\\Users\\Minhen\\.ssh\\
       id_ed25519        (PRIVATE KEY)
       id_ed25519.pub    (PUBLIC KEY)
   

3. Copy public key to VPS:

   mkdir -p ~/.ssh
   chmod 700 ~/.ssh
   nano ~/.ssh/authorized_keys
   

4. Will into a text area, then paste contents of deploy_key.pub into it