Configuring a Firewall on Your Linux Cloud Server

A firewall controls which network connections are allowed to reach your Cloud Server — an important first line of defense.

On Ubuntu or Debian (ufw)

Check the firewall's status

sudo ufw status

Allow a port

sudo ufw allow 80/tcp (replace 80 with the port you need, such as 443 for HTTPS or 22 for SSH)

Enable the firewall

sudo ufw enable — make sure you've allowed SSH (port 22) first, or you could lock yourself out.

On AlmaLinux, Rocky Linux or CentOS (firewalld)

Check the firewall's status

sudo firewall-cmd --state

Allow a service or port

sudo firewall-cmd --permanent --add-service=http, then reload with sudo firewall-cmd --reload

If you're ever unsure about a firewall change, contact our support team before applying it — an incorrect rule can block your own access to the server.