SSH is a network protocol that allows users to securely access and manage remote servers.
This time, we’ll document the detailed steps for passwordless login.
Install OpenSSH Server
Open the terminal.
Enter the following commands to install the OpenSSH server:
sudo apt update
sudo apt install openssh-server
Check SSH Server Status
Use the following command to check the SSH server’s status:
sudo systemctl status ssh
If you see “Active: active (running),” then the SSH server has started successfully.
SSH Passwordless Login Setup:
Generate SSH Key Pair on the Client
Open the terminal.
Enter the following command to generate the key pair:
ssh-keygen
Follow the prompts. The default settings are usually sufficient. When asked for a password, simply press Enter to create a key pair without a password.
Copy the Public Key to the Server
Use the ssh-copy-id command to copy the public key to the server. Replace [username] and [server-ip] with your server details.
ssh-copy-id [username]@[server-ip]
For example:
ssh-copy-id john@192.168.0.100
If the server uses a different SSH port (e.g., 2222), use the -p parameter:
ssh-copy-id -p 2222 john@192.168.0.100
This command will prompt you for the server's password.
Once verified successfully, your public key will be added to the server's ~/.ssh/authorized_keys file.
Test Passwordless Login
Try SSH into the server:
ssh [username]@[server-ip]
If everything is configured correctly, you should be able to log into the server without a password.
Disable Password Authentication
With the SSH key, you may want to disable password authentication for increased security.
This can be configured in the server’s /etc/ssh/sshd_config:
sudo vim /etc/ssh/sshd_config
Find the PasswordAuthentication option in the file and set it to no.
After completing these steps, congratulations! You can now happily use SSH without a password.