Uncomplicated FireWall Setup

Check UFW Status and Rules

At any time, you can check the status of UFW with this command: VirtualPrivateServer$sudo ufw status verbose

By default, UFW is disabled so you should see something like this:

Output:

Status: inactive

If UFW is active, the output will say that it’s active, and it will list any rules that are set. For example, if the firewall is set to allow SSH (port 22) connections from anywhere, the output might look something like this:

Configuring a Basic Firewall

This is the bare minimum firewall configuration. It will only allow traffic on your SSH port and all other services will be inaccessible. If you plan on running additional services, you will need to open the firewall at each port required.

If you plan on running an HTTP web server, you will need to allow access to port 80:
VirtualPrivateServer$sudo ufw allow 80/tcp

After you’ve finished adding the exceptions, you can review your selections by typing:
VirtualPrivateServer$sudo ufw show added

If everything looks good, you can enable the firewall by typing:
VirtualPrivateServer$sudo ufw enable

You will be asked to confirm your selection, so type "y" if you wish to continue. This will apply the exceptions you made, block all other traffic, and configure your firewall to start automatically at boot.

NB.

You will no longer be able to log in with your ssh …

VirtualPrivateServer$ssh: connect to host 159.203.92.33 port 22: Connection timed out

Remember that you will have to explicitly open the ports for any additional services that you may configure later. For more in-depth information, check out our article on configuring the ufw firewall.