Firewalls, IPS, network access control (NAC), and security information and event management (SIEM) are the four most essential components of network security. Network security isn't just about firewalls and antivirus software. Enable communication by transmitting and receiving data between devices. Allow devices to connect to networks efficiently and securely. What Are Network Security Devices? Network Security. Modern IT infrastructure is comprised of various interconnected network components that make communication and resource sharing possible throughout your organization. Others include data loss prevention (DLP); antivirus and anti-malware software; application, web and email security; and more.