DirectAdmin SSH Key Issue

Problem

DirectAdmin’s SSH Public Keys web interface (sometmes!) doesn’t work properly – it rejects all RSA and ED25519 keys with “Invalid RSA key” error, even though the keys are valid and work on other systems.

Workaround: Use DirectAdmin’s web terminal to manually add the key to ~/.ssh/authorized_keys

Solution Steps

Step 1: Generate SSH Key (Local Machine)

ssh-keygen -t rsa -b 4096 -f ~/.ssh/your_account_key -N "" -C "user@directadmin-de.kxe.io"

This creates:

  • ~/.ssh/your_account_key – Private key (keep safe)
  • ~/.ssh/your_account_key.pub – Public key (needed for server)

Step 2: Get Your Public Key (Local Machine)

cat ~/.ssh/your_account_key.pub

Copy the entire output – it looks like:

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQDSh... user@directadmin-de.kxe.io

Step 3: Access DirectAdmin Terminal

  1. Log into DirectAdmin: https://directadmin-de.kxe.io:2222/evo/login
  2. Go to Account Manager → Terminal (or Shell Access)
  3. You’ll get a web-based terminal prompt

Step 4: Create SSH Directory and Add Key (Server Terminal)

Run these commands in the DirectAdmin terminal:

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

Then paste this command (replace the key with your actual key):

echo 'ssh-rsa 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' > ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys

Step 5: Verify It Worked (Server Terminal)

cat ~/.ssh/authorized_keys

You should see your public key displayed.

Step 6: Test SSH Connection (Local Machine)

ssh -i ~/.ssh/your_account_key user@directadmin-de.kxe.io -p 10500

If successful, you’ll get a shell prompt. Type exit to disconnect.

Step 7: Add to SSH Config (Local Machine)

Edit ~/.ssh/config and add:

Host your-account-directadmin
    HostName directadmin-de.kxe.io
    User your_username
    Port 10500
    IdentityFile ~/.ssh/your_account_key
    IdentitiesOnly yes

Now you can just do:

ssh your-account-directadmin

Why This Works

  • DirectAdmin’s web interface has a bug/limitation in the SSH key field validation
  • The web terminal bypasses the buggy UI and directly creates the authorized_keys file
  • Once the key is in authorized_keys, SSH authentication works perfectly
  • The key format is standard OpenSSH format that all SSH servers accept

When to Use This

  1. First time setup of an account with SSH access
  2. If DirectAdmin UI rejects your key with “Invalid RSA key” error
  3. For multiple accounts – faster than fighting with the web interface
  4. When adding multiple keys to one account

Important Notes

  • The private key (your_account_key) stays on your local machine – NEVER share it
  • The public key (your_account_key.pub) goes on the server – this is safe to share
  • DirectAdmin terminal access is required to set up the initial key
  • After first key is added, you can add more keys via authorized_keys without needing the terminal

Troubleshooting

Still getting “Permission denied”:

  • Verify the entire public key was copied (should be one long line)
  • Check file permissions: ls -la ~/.ssh/ should show rw------- for authorized_keys
  • Verify SSH is enabled in the DirectAdmin hosting plan

Can’t access DirectAdmin terminal:

  • SSH must be enabled in your hosting plan
  • You may need to contact support to enable terminal access first

Multiple keys on same account:
Just append additional keys to authorized_keys:

echo 'ssh-rsa AAAA...second_key_here' >> ~/.ssh/authorized_keys

Example: faucetlist.org Setup

For reference, this is what was done for faucetlist.org:

  1. Generated key: ssh-keygen -t rsa -b 4096 -f ~/.ssh/faucetlist_key_rsa
  2. Accessed DirectAdmin terminal for faucetlist account
  3. Ran: mkdir -p ~/.ssh && chmod 700 ~/.ssh
  4. Pasted key: echo 'ssh-rsa AAAA...' > ~/.ssh/authorized_keys
  5. Set permissions: chmod 600 ~/.ssh/authorized_keys
  6. Tested: ssh -i ~/.ssh/faucetlist_key_rsa faucetlist@directadmin-de.kxe.io -p 10500
  7. Added to ~/.ssh/config as faucetlist-directadmin
  8. Deploy script now works: ./deploy-to-directadmin.sh