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Setting Up SSH Server on Ubuntu

· 2 min read
Zephyr
Zephyr
Engineer

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Cover image: Automatically generated by GPT-4 after reading this article.

SSH (Secure Shell) is a network protocol that allows users to securely access and manage remote servers.

This guide will walk you through setting up passwordless login.

1. Install OpenSSH Server​

Open a terminal.

Enter the following commands to install the OpenSSH server:

sudo apt update
sudo apt install openssh-server

2. Check SSH Server Status​

Use the following command to check the status of the SSH server:

sudo systemctl status ssh

If you see "Active: active (running)", then the SSH server has been successfully started.

3. Configure SSH Passwordless Login:​

3.1 Generate SSH Key Pair on the Client​

Open a terminal.

Enter the following command to generate a key pair:

ssh-keygen

Follow the prompts. The default settings are usually sufficient. You can press Enter when prompted for a passphrase to create a passphrase-less key pair.

3.2 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 is using a non-default 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 the authentication is successful, your public key will be added to the ~/.ssh/authorized_keys file on the server.

3.3 Test Passwordless Login​

Try SSHing into the server:

ssh [username]@[server-ip]

If everything is configured correctly, you should be able to log in to the server without a password.

Notes​

Using SSH key authentication indeed enhances security and convenience, but make sure not to lose your private key.

It's recommended to regularly rotate or update your SSH keys. For added security, consider disabling password authentication.

This can be configured in /etc/ssh/sshd_config on the server:

  • PasswordAuthentication no.

Once you've completed the above steps, you'll be able to log in to the server from the client without a password using SSH key authentication.