Initial Server Setup Ubuntu 22.04
From: https://www.digitalocean.com/community/tutorials/initial-server
-setup-with-ubuntu-22-04
Initial Server Setup with Ubuntu 22.04
Published on April 25, 2022
By Jamon Camisso
Introduction
When you first create a new Ubuntu 22.04 server, you should perform some
important configuration steps as part of the initial setup. These steps will
increase the security and usability of your server and will give you a solid
foundation for subsequent actions.
Step 1 — Logging in as root
To log into your server, you will need to know your server’s public IP
address. You will also need the password or the private key for the root
user’s account if you installed an SSH key for authentication. If you have
not already logged into your server, you may want to follow our guide on how
to Connect to Droplets with SSH, which covers this process in detail.
If you are not connected to your server currently, log in as the root user
using the following command. Substitute the highlighted your_server_ip
portion of the command with your server’s public IP address:
ssh root@your_server_ip
Accept the warning about host authenticity if it appears. If your server
uses password authentication, provide your root password to log in. If you
use an SSH key that is passphrase protected, you may need to enter the
passphrase the first time you use the key each session. If this is your
first time logging into the server with a password, you may also need to
change the root password. Follow the instructions to change the password if
you receive a prompt.
About root
The root user is the administrative user in a Linux environment with
elevated privileges. Because of the heightened privileges of the root
account, you are discouraged from using it regularly. The root account can
make very destructive changes, even by accident.
The next step is setting up a new user account with reduced privileges for
day-to-day use. Later, we’ll show you how to temporarily gain increased
privileges for the times when you need them.
Step 2 — Creating a New User
Once you log in as root, you’ll be able to add the new user account. In
the future, we’ll log in with this new account instead of root.
This example creates a new user called sammy, but you should replace that
with a username that you like:
adduser sammy
You will be asked a few questions, starting with the account password.
Enter a strong password and, optionally, fill in any of the additional
information if you would like. This information is not required, and you can
press ENTER in any field you wish to skip.
Step 3 — Granting Administrative Privileges
Now you have a new user account with regular account privileges. However,
you will sometimes need to perform administrative tasks as the root user.
To avoid logging out of your regular user and logging back in as the root
account, you can set up what is known as superuser or root privileges for
your user’s regular account. These privileges will allow your normal user
to run commands with administrative privileges by putting the word sudo
before the command.
To add these privileges to your new user, you will need to add the user to
the sudo system group. By default on Ubuntu 22.04, users who are members of
the sudo group are allowed to use the sudo command.
As root, run this command to add your new user to the sudo group (substitute
the highlighted sammy username with your new user):
usermod -aG sudo sammy
You can now type sudo before commands to run them with superuser privileges
when logged in as your regular user.
Step 4 — Setting Up a Firewall
Ubuntu 22.04 servers can use the UFW firewall to ensure only connections to
certain services are allowed. You can set up a basic firewall using this
application.
Note:
If your servers are running on DigitalOcean, you can optionally use
DigitalOcean Cloud Firewalls instead of the UFW firewall. We recommend using
only one firewall at a time to avoid conflicting rules that may be difficult
to debug.
Applications can register their profiles with UFW upon installation. These
profiles allow UFW to manage these applications by name. OpenSSH, the
service that allows you to connect to your server, has a profile registered
with UFW.
You can examine the list of installed UFW profiles by typing:
ufw app list
Output
Available applications:
OpenSSH
You will need to make sure that the firewall allows SSH connections so that
you can log into your server next time. Allow these connections by typing:
ufw allow OpenSSH
Now enable the firewall by typing:
ufw enable
Type y and press ENTER to proceed. You can see that SSH connections are
still allowed by typing:
ufw status
Output
Status: active
To Action From
-- ------ ----
OpenSSH ALLOW Anywhere
OpenSSH (v6) ALLOW Anywhere (v6)
Tthe firewall is currently blocking all connections except for SSH. If you
install and configure additional services, you will need to adjust the
firewall settings to allow the new traffic into your server. You can learn
some common UFW operations in our UFW Essentials guide.
Step 5 — Enabling External Access for Your Regular User
Now that you have a regular user for daily use, you will need to make sure
that you can SSH into the account directly.
Note:
Until verifying that you can log in and use sudo with your new user, we
recommend staying logged in as root. If you have problems connecting, you
can troubleshoot and make any necessary changes as root. If you use a
DigitalOcean Droplet and experience problems with your root SSH connection,
you can regain access to Droplets using the Recovery Console.
Configuring SSH access for your new user depends on whether your server’s
root account uses a password or SSH keys for authentication.
If the root Account Uses Password Authentication
If you logged in to your root account using a password then password
authentication is enabled for SSH. You can SSH to your new user account by
opening up a new terminal session and using SSH with your new username:
ssh sammy@your_server_ip
After entering your regular user’s password, you will be logged in.
Remember, if you need to run a command with administrative privileges, type
sudo before it like this:
sudo command_to_run
You will receive a prompt for your regular user’s password when using sudo
for the first time each session (and periodically afterward).
To enhance your server’s security, we strongly recommend setting up SSH
keys instead of using password authentication. Follow our guide on setting
up SSH keys on Ubuntu 22.04 to learn how to configure key-based
authentication.
If the root Account Uses SSH Key Authentication
If you logged in to your root account using SSH keys, then password
authentication is disabled for SSH. To log in as your regular user with an
SSH key, you must add a copy of your local public key to your new user’s
~/.ssh/authorized_keys file.
Since your public key is already in the root account’s
~/.ssh/authorized_keys file on the server, you can copy that file and
directory structure to your new user account using your current session.
The simplest way to copy the files with the correct ownership and
permissions is with the rsync command. This command will copy the root
user’s .ssh directory, preserve the permissions, and modify the file
owners, all in a single command. Make sure to change the highlighted
portions of the command below to match your regular user’s name:
Note:
The rsync command treats sources and destinations that end with a trailing
slash differently than those without a trailing slash. When using rsync
below, ensure that the source directory (~/.ssh) does not include a trailing
slash (check to make sure you are not using ~/.ssh/).
If you accidentally add a trailing slash to the command, rsync will copy the
contents of the root account’s ~/.ssh directory to the sudo user’s home
directory instead of copying the entire ~/.ssh directory structure. The
files will be in the wrong location and SSH will not be able to find and use
them.
rsync --archive --chown=sammy:sammy ~/.ssh /home/sammy
Now, open up a new terminal session on your local machine, and use SSH with
your new username:
ssh sammy@your_server_ip
You should be connected to your server with the new user account without
using a password. Remember, if you need to run a command with administrative
privileges, type sudo before the command like this:
sudo command_to_run
You will be prompted for your regular user’s password when using sudo for
the first time each session (and periodically afterward).
Where To Go From Here?
At this point, you have a solid foundation for your server. You can install
any of the software you need on your server now.
If you’d like to get more familiar with Linux commands, you can check our
Linux Command Line Primer.