Creating a Password-Free Connection Between Two Servers with Proper Permissions

Creating a Password-Free Connection Between Two Servers with Proper Permissions

Setting up a password-free SSH connection between two servers, A and B, enhances security and efficiency. This guide will walk you through establishing a secure, key-based connection, ensuring all permissions are correctly set to 600 for safety.

Step 1: Generate SSH Keys

• On Both Server A and B:
• 
  
  1. Run ssh-keygen to create a pair of keys: id_rsa (private) and id_rsa.pub (public).
  2. Ensure the permissions of these keys are set to 600.

Step 2: Exchange Public Keys

• On Server A:
  1. Copy the id_rsa.pub of Server A to the authorized_keys file of Server B.
• On Server B:
  1. Similarly, copy the id_rsa.pub of Server B to the authorized_keys file of Server A.

Connecting Using Private Key:

• To connect to Server A from B (or vice versa), use the private key (id_rsa) with the following command:

  ssh user@xxx.xxx.xxx.xxx -i <path-to-private-key>
  

  Replace xxx.xxx.xxx.xxx with the actual server IP and specify the correct path to your private key.

Additional Tips:

• From any other server (say Server Z with IP zzz.zzz.zzz.zzz), you can use the ssh-copy-id command to easily copy your public key to Servers A or B:

  ssh-copy-id root@zzz.zzz.zzz.zzz

• Reverse the process to allow the opposite connection.

Important Notes:

• Always ensure your keys' permissions are set to 600 to prevent unauthorized access.
• Regularly update and rotate your keys for enhanced security.

By following these steps, you'll establish a secure, password-free connection between two servers, ensuring efficient and safe operations.