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Ubuntu 18.04 – Firewall Setup

Setting Up a Basic Firewall

Ubuntu 18.04 servers can use the UFW firewall to make sure only connections to certain services are allowed. We can set up a basic firewall very easily using this application.

Different applications can register their profiles with UFW upon installation. These profiles allow UFW to manage these applications by name. OpenSSH, the service allowing us to connect to our server now, has a profile registered with UFW.

$ ufw app list
$ ufw allow OpenSSH
$ ufw enable
$ ufw status

As the firewall is currently blocking all connections except for SSH, if you install and configure additional services, you will need to adjust the firewall settings to allow acceptable traffic in. 

  • After NginX Install

$ ufw app list

The output is as follow

Available applications:
  Nginx Full
  Nginx HTTP
  Nginx HTTPS
  OpenSSH
  • Nginx Full: This profile opens both port 80 (normal, unencrypted web traffic) and port 443 (TLS/SSL encrypted traffic)
  • Nginx HTTP: This profile opens only port 80 (normal, unencrypted web traffic)
  • Nginx HTTPS: This profile opens only port 443 (TLS/SSL encrypted traffic)

$ ufw allow ‘Nginx HTTP’
$ ufw status

$ ufw delete number (or ufw delete allow ‘RULE’)