Ubuntu VPS First-Day Security Setup

Step 1

Install available updates

Refresh package information and install current updates. Review the package list and schedule a reboot if the kernel or critical libraries changed.

sudo apt update
sudo apt upgrade

Step 2

Create a named administrator

Replace USERNAME with a real account name, then set a unique password when prompted.

sudo adduser USERNAME
sudo usermod -aG sudo USERNAME

Step 3

Add an SSH public key

Sign in as the named user and place your public key in ~/.ssh/authorized_keys with restrictive permissions. Never place the private key on the server.

mkdir -p ~/.ssh
chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

Step 4

Configure the firewall

Allow the active SSH service before enabling UFW. Add only the web or application ports the workload needs.

sudo ufw allow OpenSSH
sudo ufw enable
sudo ufw status verbose

Step 5

Harden SSH after testing

After key login succeeds in a second session, review sshd_config settings for root login and password authentication. Validate configuration before reloading the service.

sudo sshd -t

Step 6

Record a recovery baseline

Document open ports, enabled services, administrator accounts, and the backup location so future changes can be audited.