Setting up a Firewall in a Ubuntu Server

Uncomplicated Firewall offers the most basic security configuration for Ubuntu by deafult. Providing a very user friendly firewall for both IPv4 and IPv6.

By default it is loaded in Ubuntu but disabled.

Its configuration is easy and is offered via command line and or a graphiicalinterface for frontend called Gufw.

In this article, well take you through an easy set upand configuration.

Enable UFW

To enable ufw, run this command.

sudo ufw enable

Check the  status by running

sudo ufw status

If the VPS is configured for both IPv4 and IPv6, make sure you configure rules for both. Tho do this, run

sudo nano /etc/default/ufw

and set the value for IPv6 to “YES”

Close the editor by pressing “Ctrl+X” then save the changes.

Restart the firewall by

sudo ufw disable
sudo ufw enable

Set up rules

Setting up some rules to allow and deny rules is easy and simple.

sudo ufw default deny incoming

sudo ufw default allow outgoing

To prevent remote shell connections on a public cloud, you can be more restrictive and deny all outgoing requests. However, this makes the management more cumbersome.

sudo ufw default deny outgoing

Allowing connections

By blocking all incoming requests, SSH was blocked as well and that means you cannot access the server through SSH. You need change the rules to allow SSH to connect.

sudo ufw allow ssh