Ubuntu Firewall (UFW)

UFW, which stands for Uncomplicated Firewall, is a user-friendly front-end for managing IPTables. It is the primary firewall used across UTN systems.

Commonly allowed ports/services, also known as rules, on most UTN systems (applicable to both IPv4 and IPv6) include:

  • ssh: Allows SSH access to the server.
  • 80/tcp: Permits HTTP traffic to the server.
  • 443/tcp: Enables HTTPS traffic to the server.

Avoid enabling 25/tcp for SMTP traffic unless the mail server ( Postfix) is properly secured against unauthorized access.

Useful Commands #

Here are some essential UFW commands to remember:

  • ufw allow [rule]: Opens the firewall to allow traffic that matches the specified rule.
  • ufw delete allow [rule]: Removes an allow rule that was previously set.
  • ufw show added: Displays the rules that will be activated upon the next reload.
  • ufw enable: Activates the UFW firewall.
  • ufw status: Shows the rules currently enforced by the firewall.

Execute these commands with root privileges.