Firewalls are considered the key element in securing networks. A firewall is usually a computer that sits on two different networks and passes allowed traffic between them, filtering out traffic that is not permitted. A firewall is the primary deterrence device used in a network. Its job is similar to a physical firewall that keeps a fire from spreading from one area to the next. The purpose of this session is to learn more about firewalls, how they work and what kinds of threats they can protect you from.
Read through the attached Notes and try to comprehend the firewall principle and its role in protecting the corporate network. As an exercise, you may think upon the following issues: