The firewall creates a virtual wall around the company's network, acting as a security guard on any traffic that wants to come in, keeping all the internal company assets safe and authorizing
permitted visitors access.

There may also be a semi-trusted area called a de-militarized zone, a DMZ. This is a controlled place area for things that are not completely trusted, or it is where you allow visitors to come into the network but not fully.

Learn more about firewalls on www.eset.com/blog/