Description: In this exercise you will be asked to describe the purpose and advantages of using Firewalls and DMZs. Then you will design a network architecture that allows users in the untrusted domain to communicate with systems in the trusted domain employing the use of Firewall and DMZ. You will be asked how to harden the DMZ and asked where you would sniff traffic and why.

Components and Concepts:

Firewall - A firewall is a network security device that allows or rejects digital information between network zones of various trust levels (e.g., the Internet, DMZ, LAN). Firewalls can be used as Gateways, Control Points, Filters, or Internal Firewalls.

DMZ - Demilitarized zone can be thought of as a perimeter network. It is s a physical or logical network arm that contains and exposes an organization's external-facing services to a larger and untrusted network. You use a DMZ to add an additional layer of security between your external facing systems and your internal network.

Question 1: Design a Simple network architecture that allows users in the untrusted domain to communicate with systems in the trusted domain employing the use of Boundary Router, SMPT Server, Firewall(s) and DMZ. Explain your design from a security perspective. From the design also add sensor point indicators on your design to show where you would sniff traffic with one or more Network-Based Intrusion Detection Systems (NIDS). Explain what the reasoning is (what you expect to detect) from a security perspective. Are there any potential drawbacks to consider?