Theory

An Intrusion Prevention System (IPS) is a security tool that actively monitors network traffic for malicious activity. It analyzes data in real-time to identify known attack patterns, unusual behavior, and other threats. When an attack is detected, the IPS takes immediate action to block it, safeguarding the network and its resources. IPS solutions can be deployed at the network perimeter, in the data center, or on individual endpoints, making them a crucial part of modern cybersecurity.

Two popular examples of IPS are:

• Cisco's Firepower IPS: This system uses a combination of signature-based detection and machine learning to identify and stop a wide range of network attacks, including malware and DDoS attacks.
• Suricata: An open-source IPS that employs signature-based and anomaly detection techniques to prevent intrusions and exploitation of vulnerabilities.

A firewall is another essential network security device that acts as a filter for incoming and outgoing traffic. Based on a set of predefined security rules, it permits or denies traffic to prevent unauthorized access to a private network. For instance, a firewall can be configured to allow web browsing traffic (port 80) while blocking protocols commonly used for other services. Firewalls serve as the first line of defense in network security and can be hardware-based, software-based, or implemented in the cloud.

While both IPS and firewalls are vital for network security, they serve different functions. A firewall enforces access control policies by filtering traffic based on rules (e.g., ports, IP addresses). An IPS, on the other hand, inspects the content of the traffic that the firewall allows through, looking for malicious patterns or anomalous activity.

By combining a firewall and an IPS, organizations can build a more robust, multi-layered security posture. The firewall provides the initial barrier, blocking obviously malicious or unauthorized traffic. The IPS then adds a deeper layer of inspection, detecting and preventing sophisticated attacks that might otherwise bypass the firewall. This synergistic relationship ensures that networks are protected against a wider range of both known and unknown threats.