The fundamental purpose of Computer Network Defense (CND) is to protect computer networks from unauthorized access, misuse, and cyberattacks. CND ensures the confidentiality, integrity, and availability of data by monitoring, detecting, responding to, and preventing threats. It helps organizations avoid data breaches, service disruptions, and financial loss.One key element of CND is the Intrusion Detection System (IDS). An IDS monitors network traffic for suspicious activity and sends alerts when it detects potential threats. It acts like a security camera for the network, watching for abnormal behavior or known attack patterns. For example, if someone tries to access a server repeatedly with incorrect passwords, the IDS will notice and alert the administrators. This allows the organization to take immediate action before the attack causes damage.CND also includes tools like firewalls, antivirus software, and encryption, but human decision-making and updated policies are equally important. CND is a combination of technology, procedures, and trained personnel working together to ensure that networks are safe and reliable.