The Connection of Aninternal Network to an External Network Such As Internet Has Made It Vulnerableto Attacks. One Class of Network Attack Is Unauthorized Penetration Intonetwork Due to the Openness of Networks. It Is Possible For Hackers to Sumaccess to an Internal Network, This Pose Great Danger to the Network and Networkresources. Our Objective and Major Concern of Network Design Was to Build Asecured Network, Based on Software Firewall That Ensured the Integrity Andconfidentiality of Information on the Network. We Studied Several Mechanisms Toachieve This; One of Such Mechanism Is the Implementation of Firewall System Asa Network Defense. Our Developed Firewall Has the Ability to Determine Whichnetwork Traffic Should Be Allowed In or Out of the Network. Part of Our Studiedwork Was Also Channeled Towards a Comprehensive Study of Hardware Firewallsecurity System With the Aim of Developing This Software Based Firewall System.Our Software Firewall Goes a Long Way In Protecting an Internal Network Fromexternal Unauthorized Traffic Penetration. We Included Anti-Virus Softwarewhich Is Lacking In Most Firewall.