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NodeJS is a server-side implementation of javascript. It is event-driven and asynchronous so it is often used as a partial replacement for PHP.

In Ubuntu, there is an application called UFW (Uncomplicated Firewall) that makes it much easier to manage IPTables in Ubuntu. As such, IPTables is the firewall of Linux systems, but it is somewhat difficult to work with. But, UWF is very easy to use.