Root Login

You will need to know your server’s public IP address and the password for the “root” user’s account.

Connect To Your Server with SSH

In order to connect to a remote Linux server via SSH, you must have following:

• User name: The remote user to log in as. The default admin user, on most Linux servers is root
• Password and/or SSH Key: The password that is used to authenticate the user that you are logging in as. If you added a public SSH key to your server when you created it, you must have the private SSH key of the key pair (and passphrase, if it has one)
• Server IP address.

SSH Client Software

PuTTY (Windows): A free SSH client that can run on Windows, and is available for download on the PuTTY Download Page. putty.exe is the SSH client, and puttygen.exe should also be downloaded if you want to use SSH keys.

SSH Login as Root

Run putty.exe; 

Configure the Connection

To properly configure the the SSH connection in putty, ensure that the following settings are set:

• Host Name (or IP address): Enter your server’s IP address here
• Port: 22 (default)
• Connection Type: SSH (default)

Initiate the Connection

To initiate the connection, double-click on the session name, and accept the security alert (this will only appear the first time you connect to a server).

Authenticate

Follow these steps to complete the login process:

1. At the login as prompt, enter root
2. At the Password prompt, enter the password that was emailed to you (copy and paste it)
3. At the (current) UNIX password prompt, paste in the temporary password again
4. At the Enter new UNIX password prompt, enter a strong password
5. At the Retype new UNIX password prompt, enter the same strong password that you just entered

Don’t forget the new password that you set.

Create a New User

Once you are logged in as root :

In this example we’ll create a new user called “demo”:

adduser demo

Next, assign a password to the new user (again, substitute “demo” with the user that you just created):

passwd demo

Enter a strong password, and repeat it again to verify it.

Root Privileges

By putting the word sudo before each command, This will allow our normal user to run commands with administrative privileges.

As root, run this command to add your new user:

gpasswd -a demo wheel

Add Public Key Authentication (Recommended)

Generate a Key Pair will increase the security of your server by requiring a private SSH key to log in.

To generate a new key pair:

ssh-keygen

Generating public/private rsa key pair.
Enter file in which to save the key (/Users/localuser/.ssh/id_rsa):

Copy the Public Key

Use ssh-copy-id

If your local machine has the ssh-copy-id script installed, you can use it to install your public key to any user that you have login credentials for.

ssh-copy-id demo@SERVER_IP_ADDRESS

Your public key will be added to the remote user’s .ssh/authorized_keys file.

Configure SSH Daemon

Open the configuration file with your text editor as root:

vi /etc/ssh/sshd_config

To disable remote root logins, we need to find the line that looks like this:

#PermitRootLogin yes

Replace ‘yes’ by ‘no’ and save.

Reload SSH

Type this to restart SSH:

systemctl reload sshd

Test the new configuration

ssh demo@SERVER_IP_ADDRESS

sudo command_to_run