UFW, short for Uncomplicated Firewall, is basically a simplified firewall mechanism that is implemented upon IPtables itself, making it much easier to configure UFW than to configure IPtables. Therefore, it can be said that UFW is technically a program for managing a netfilter firewall which aims to provide an easy to use interface for the user.
The Need for UFW: Uncomplicated Firewall
Consider a situation where protocols like ssh, ftp, etc., which if left open for everyone and anyone to connect, might result in a massive security breach by the attackers or malicious users. Hence, this originated the need for a firewall. Firewall is useful to us in a way, that it allows us the remote access to the system but in a limited fashion. A simple example would be, firewall can allow certain ports to be left open to only a few IP addresses to limit security breach and also allowing connections to only a trusted device.