Password-less SSH connection

Password-less SSH connection

Creating a password-less SSH connection between Linux servers or between a Linux server and a Windows server involves generating SSH key pairs and configuring SSH access. Here's how you can do it:

For Linux to Linux and Linux to Windows – we recommend ed25519 instead of rsa ( refer the documentation for more details ). If any reason it is not supported in your windows version, You may use rsa

Linux to Linux Servers:

1. Generate SSH Key Pair: Run the following command on the source server:

bash

ssh-keygen -t ed25519

2. Follow the prompts to generate the SSH key pair.

3. Copy Public Key to the Destination Server: Use ssh-copy-id or manually copy the public key to the destination server:

bash

ssh-copy-id username@destination_server_ip

You'll need to enter the password for the destination server's user account.

3. Test the Connection: Try connecting to the destination server without a password:

bash

ssh username@destination_server_ip

Linux to Windows Server (using OpenSSH):

1. Generate SSH Key Pair: Run the following command on the Linux server:

bash

ssh-keygen -t ed25519
ssh-keygen -t rsa ( not recommend unless you are using older versions of Windows)

2. Follow the prompts to generate the SSH key pair.

3. Install OpenSSH Server on Windows: If not already installed, install the OpenSSH server feature on the Windows server.

4. Copy Public Key to the Windows Server:

• Manually copy the public key generated on the Linux server ( ~/.ssh/id_ed25519.pub) or (~/.ssh/id_rsa.pub) to the Windows server:
• Create the .ssh directory in the Windows user's home directory (C:\Users\username\.ssh).
• Copy the contents of the public key (id_ed25519.pub) or (id_rsa.pub) to a file named authorized_keys inside the .ssh directory.

For some Windows versions, Follow this method

5. Copy the public key to the Windows Server:

bash

scp ~/.ssh/id_ed25519.pub Administrator@192.168.1.100:'C:\ProgramData\ssh\administrators_authorized_keys'

6: Set Correct ACLs for Authorized Keys

On the Windows Server, set the correct ACLs for the authorized keys:

powershell

icacls.exe "C:\ProgramData\ssh\administrators_authorized_keys" /inheritance:r /grant "Administrators:F" /grant "SYSTEM:F"

7. Restart the SSH service:

powershell

Restart-Service sshd

5. Test the Connection: Try connecting to the Windows server from the Linux server without a password:

bash

ssh username@windows_server_ip

Note:

• Ensure SSH server is running and accessible on the destination server.
• Adjust firewall rules to allow SSH connections.
• Properly secure SSH configurations to enhance security.
• For Windows servers, ensure OpenSSH server feature is enabled and properly configured.

Once configured, you'll be able to SSH between the servers without entering a password.