SSH Key Setup for GitHub, GitLab, Proxmox, and Raspberry Pi

This guide provides a comprehensive approach to managing SSH keys across multiple services in a Windows environment. Whether you’re connecting to GitHub, GitLab, Proxmox, or Raspberry Pi devices, this setup ensures secure and convenient access through PowerShell integration.

Key features of this setup:

• Separate SSH keys for each service for enhanced security
• PowerShell functions for quick access to different services
• Automated SSH agent configuration
• Regular key rotation and maintenance procedures
• Windows-specific considerations and best practices

This configuration is particularly useful for developers and system administrators who need to manage multiple SSH connections while maintaining security best practices.

🛠️ SSH Key Generation

Generate a unique ED25519 key for each service. Using separate keys for different services enhances security through isolation:

ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519_github -C "github key"
ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519_gitlab -C "gitlab key" 
ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519_proxmox -C "proxmox key"
ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519_rpi5 -C "rpi5 key"

⚠️ On Windows, ensure the ~/.ssh/ directory exists:

mkdir ~\.ssh

Adding Public Keys to Services

GitHub

1. Open your public key file:
   • Navigate to C:\Users\YourUsername\.ssh\
   • Open id_ed25519_github.pub in a text editor
   • Copy the entire content (starts with ssh-ed25519 and ends with your email)
2. Go to GitHub → Settings → SSH and GPG keys → New SSH key
3. Give it a title (e.g., “Windows Laptop”)
4. Paste the key and click “Add SSH key”

GitLab

1. Open your public key file:
   • Navigate to C:\Users\YourUsername\.ssh\
   • Open id_ed25519_gitlab.pub in a text editor
   • Copy the entire content
2. Go to GitLab → Preferences → SSH Keys
3. Paste the key, add a title, and click “Add key”

Proxmox

1. Open your public key file:
   • Navigate to C:\Users\YourUsername\.ssh\
   • Open id_ed25519_proxmox.pub in a text editor
   • Copy the entire content
2. SSH into your Proxmox host using password authentication
3. Create or edit the authorized_keys file:

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

4. Paste your public key on a new line
5. Save the file (Ctrl+O, then Enter) and exit (Ctrl+X)
6. Set proper permissions:

   chmod 700 ~/.ssh
   chmod 600 ~/.ssh/authorized_keys
   

Raspberry Pi

1. Open your public key file:
   • Navigate to C:\Users\YourUsername\.ssh\
   • Open id_ed25519_rpi5.pub in a text editor
   • Copy the entire content
2. SSH into your Raspberry Pi using password authentication
3. Create or edit the authorized_keys file:

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

4. Paste your public key on a new line
5. Save the file (Ctrl+O, then Enter) and exit (Ctrl+X)
6. Set proper permissions:

   chmod 700 ~/.ssh
   chmod 600 ~/.ssh/authorized_keys
   

🔐 SSH Config Setup (~/.ssh/config)

Create or edit your SSH config file to manage multiple service connections. This configuration enables easy switching between different services:

Host github
    HostName github.com
    User git
    IdentityFile C:/Users/srees/.ssh/id_ed25519_github
    IdentitiesOnly yes

Host gitlab
    HostName gitlab.com
    User git
    IdentityFile C:/Users/srees/.ssh/id_ed25519_gitlab
    IdentitiesOnly yes

Host proxmox
    HostName proxmox.local # or your internal IP like 192.168.1.50
    User root
    Port 22
    IdentityFile C:/Users/srees/.ssh/id_ed25519_proxmox
    IdentitiesOnly yes

Host rpi5
    HostName raspberrypi5.local
    User rpi
    Port 22065
    IdentityFile C:/Users/srees/.ssh/id_ed25519_rpi5
    IdentitiesOnly yes

Host rpi4
    HostName rpimaster4.local
    User rpi
    Port 22
    IdentityFile C:/Users/srees/.ssh/id_ed25519_rpi5
    IdentitiesOnly yes

⚙️ PowerShell Function Setup

Edit your PowerShell profile to create convenient aliases for SSH connections:

notepad $PROFILE

Add these functions for quick access:

function rpi5 { ssh rpi5 }
function rpi4 { ssh rpi4 }
function proxmox { ssh proxmox }
function github { ssh github }
function gitlab { ssh gitlab }

Then reload the profile:

. $PROFILE

🔑 Key Rotation and Maintenance

Regular key rotation is essential for maintaining security. Here’s how to manage your SSH keys:

Key Rotation Process

1. Generate New Keys

   # Generate new key with a date suffix
   ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519_github_new -C "github key $(Get-Date -Format 'yyyy-MM')"
   

2. Update Services
   • Add the new public key to each service
   • Test the new key works
   • Remove the old key from services
   • Keep old keys for 30 days before deletion (in case of issues)
3. Update Config
   • Modify ~/.ssh/config to point to new key files
   • Test all connections
   • Remove old key files after the grace period

Maintenance Schedule

• Rotate keys every 6-12 months
• Review key permissions quarterly
• Backup SSH config and keys regularly
• Document any changes to key configurations

✅ Usage

You can now SSH into each system with a simple command:

rpi5
proxmox
github
gitlab

📌 Notes and Best Practices

• Make sure each service has its public key added (e.g., GitHub SSH settings, ~/.ssh/authorized_keys on RPi).
• Always prefer ed25519 for secure and fast key generation.
• Keep a secure backup of your SSH keys and config
• Document any custom configurations or non-standard setups
• Regularly audit your SSH keys and remove unused ones