This report provides a comprehensive overview of network security, focusing on the importance of securing systems against unauthorized access and risks. It delves into various aspects of network security, including the use of firewalls, intrusion detection systems, and VPNs. The report discusses the different types of firewalls, such as packet filters, stateful inspection firewalls, and circuit-level gateways, along with their respective security threats like IP spoofing and source routing attacks. It also highlights the significance of software tools like antivirus and intrusion detection systems in safeguarding computer systems. The report further emphasizes the importance of proper firewall configuration, addressing issues such as missed security patches and configuration mistakes. Finally, it covers the design and implementation of network security systems, including the use of VPNs to ensure secure connections. This report aims to provide a thorough understanding of network security principles and practices, equipping readers with the knowledge to protect their networks effectively.