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Git SSH Setup

Generate SSH Key

ssh-keygen -t ed25519 -C "your_email@example.com"
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

ssh-keygen -t ed25519 -C "your_email@example.com"
Get-Service ssh-agent | Set-Service -StartupType Automatic
Start-Service ssh-agent
ssh-add $env:USERPROFILE\.ssh\id_ed25519

Copy Public Key

pbcopy < ~/.ssh/id_ed25519.pub

cat ~/.ssh/id_ed25519.pub

Get-Content $env:USERPROFILE\.ssh\id_ed25519.pub | Set-Clipboard

Add SSH Key to GitHub

  1. Go to GitHub SSH Settings
  2. Click New SSH key
  3. Give it a title (e.g., "Work Laptop")
  4. Paste your public key
  5. Click Add SSH key

NOTE: See GitHub's official guide: Adding a new SSH key to your GitHub account

SSH Config (Port 443)

Why Port 443?

Many corporate firewalls block port 22 (default SSH port). GitHub allows SSH connections over port 443 (HTTPS port) which is usually open.

Edit ~/.ssh/config:

Host github.com
    HostName ssh.github.com
    Port 443
    User git
    IdentityFile ~/.ssh/id_ed25519

Edit C:\Users\<username>\.ssh\config:

Host github.com
    HostName ssh.github.com
    Port 443
    User git
    IdentityFile C:\Users\<username>\.ssh\id_ed25519

Test Connection

ssh -T git@github.com

Expected output:

Hi username! You've successfully authenticated, but GitHub does not provide shell access.

Multiple Git Profiles

If you have multiple GitHub accounts (e.g., personal and work), you can configure separate SSH keys and profiles.

Step 1: Generate Separate Keys

# Personal account
ssh-keygen -t ed25519 -C "personal@email.com" -f ~/.ssh/id_ed25519_personal

# Work account
ssh-keygen -t ed25519 -C "work@company.com" -f ~/.ssh/id_ed25519_work

Step 2: Add Keys to SSH Agent

ssh-add ~/.ssh/id_ed25519_personal
ssh-add ~/.ssh/id_ed25519_work

ssh-add $env:USERPROFILE\.ssh\id_ed25519_personal
ssh-add $env:USERPROFILE\.ssh\id_ed25519_work

Step 3: Configure SSH Config

Edit ~/.ssh/config (or C:\Users\<username>\.ssh\config on Windows):

# Personal GitHub
Host github.com
    HostName ssh.github.com
    Port 443
    User git
    IdentityFile ~/.ssh/id_ed25519_personal

# Work GitHub (use custom host alias)
Host github_work
    HostName ssh.github.com
    Port 443
    User git
    IdentityFile ~/.ssh/id_ed25519_work

Step 4: Add Keys to GitHub Accounts

Add each public key to its respective GitHub account:

  • Personal: Add id_ed25519_personal.pub to your personal GitHub
  • Work: Add id_ed25519_work.pub to your work GitHub

Step 5: Clone Using Profile

# Personal (default)
git clone git@github.com:personal-user/repo.git

# Work (use custom host)
git clone git@github_work:work-org/repo.git

Step 6: Configure Git User Per Repository

After cloning, set the correct user for each repo:

cd /path/to/work/repo
git config user.name "Your Work Name"
git config user.email "work@company.com"

TIP: For automatic user config based on folder, see Conditional Git Config.

Troubleshooting

Permission denied (publickey)

# Check which key is being used
ssh -vT git@github.com

# Verify key is added to agent
ssh-add -l

Connection timed out

Your firewall may be blocking port 22. Use port 443 config above.

Multiple profiles not working

Make sure you're using the correct host alias in your git remote:

# Check current remote
git remote -v

# Update to use correct profile
git remote set-url origin git@github_work:org/repo.git