How to connect server to server explained in 5 simple steps anyone can follow.

Connecting servers securely is foundational to system administration and cloud operations. Follow these essential steps:

1. Configure SSH Access

Ensure Secure Shell (SSH) is enabled and configured on the target server. Open the SSH port (default TCP 22) in the firewall rules. Verify connectivity using:

ssh username@target_server_ip

This tests basic network reachability and service availability.

2. Generate SSH Key Pair

On the source server, create an SSH key pair for passwordless authentication:

ssh-keygen -t rsa -b 4096

Store keys in the default location (~/.ssh/) without a passphrase for automated processes, though this reduces security.

3. Copy Public Key to Target Server

Transfer the public key (id_*) to the target server's ~/.ssh/authorized_keys file using:

ssh-copy-id username@target_server_ip

Manually append the key if ssh-copy-id is unavailable.

4. Verify Key-Based Authentication

Attempt SSH login from the source server. It should connect without password prompts:

ssh username@target_server_ip

If authentication fails, verify file permissions on the target:

• ~/.ssh directory: 700
• authorized_keys file: 600

5. Harden SSH Configuration

Enhance security on the target server by editing /etc/ssh/sshd_config:

• Disable password authentication: PasswordAuthentication no
• Restrict root login: PermitRootLogin no
• Change default SSH port (optional)

Reload the SSH service after modifications.