How to set up UFW on Ubuntu 16.4?

Question

ubuntu

I am practically unfamiliar with Linux systems, I recently bought a VDS, played around and studied, with Ubuntu preinstalled there, I wanted to raise a .Net Core application there, at the same time setting up a firewall.
Found a short tutorial online.
I write commands:
sudo ufw allow http
sudo ufw allow https
sudo ufw allow ssh

Then I enter sudo ufw enable and get an error like


What am I doing wrong?

Answer 1

This is a feature of Ubuntu running under OpenVZ virtualization.
Do as it is written here: https://blog.kylemanna.com/linux/ufw-vps/