Tom Bienkowski, Director of Product Marketing

Tom Bienkowski

Director, Product Marketing

Last Updated
What is IDS?

What is a Network Intrusion Detection System (IDS)?

An intrusion detection system (IDS) is an application or appliance used to monitor traffic across a network and/or technology systems. Network IDS systems allow IT professionals to identify suspect activities and documented threats. The IDS analyzes traffic and looks for patterns in the network traffic that is indicative of a cyberattack, such phishing attacks that include a link that will automatically download malicious malware. Once a network intrusion is detected, the system issues an alert containing vital information, such as the source address of the incursion, as well as the target address and the type of attack.

Network IDS solutions come in several forms, including host-based and network-based systems, depending on where the sensors are placed. These systems can be segmented further as perimeter IDS, VM-based IDS, stack-based IDS, signature-based IDS and anomaly-based IDS.

What is an Intrusion Prevention System (IPS)?

An Intrusion Prevention System (IPS) is network security and threat prevention technology that analyzes network traffic to uncover and prevent attacks. IPS seeks to prevent bad actors from gaining control of vital applications or systems, causing distributed denial of service (DDoS) attacks, or obtaining access to the rights and permissions of applications.

An IPS is generally placed behind the firewall. Instead of being a passive monitoring system, such as a network IDS system, IPS sits directly in the middle of the communication path between source and destination and actively prevents attacks by dropping suspect packets, blocking traffic from malicious sources, and reestablishing connections automatically.

IPS uses either signature-based detection or statistical anomaly-based detection to respond accurately to attacks. Signature-based detection is based on established threat signatures found in the code. Statistical anomaly detection collects samples of network traffic randomly and then makes comparisons to pre-established baseline performance levels. Anything that is outside the baseline parameters of normal network traffic activity causes the IPS to take corrective action.

Do I need both Network IDS and IPS?

IDS and IPS are critical security components. An IDS is a tool designed to monitor network events meticulously, detecting potential security incidents and threats. An IPS goes a step further by not only identifying threats like an IDS, but also providing control by preventing these detected threats, offering a robust defense against attacks. To get the best of both worlds, hybrid solutions offer a blend of threat detection capabilities of IDS with the threat prevention advantages of IPS, resulting in comprehensive network security.

If budgets are constrained, and an organization can only choose one solution, an IDS solution should be the preference. Network IDS systems provide much-needed visibility into threats, but this solution alone requires regular and active response to any detected issues. This takes time and manpower. Conversely, the automated response of an IPS makes it more effective in protecting systems. But here, too, the solution is only effective if it is tuned to meet network and application usage. Failure to adequately tune the solution will result in a high rate of false positives that can interrupt legitimate traffic. IPS systems are also effective at detecting problems caused by human error, which tend to be more common than targeted attacks.

Is an Intrusion Prevention System (IPS) the same as a Web Application Firewall (WAF)?

While IPS and WAF are both focused on network security, they each function differently. WAF blocks and filters incoming and outgoing traffic, while IPS detects and alerts security professionals of an incursion, or takes automated action to prevent the attack, depending on the configuration.

An IPS is installed after the firewall in layer 2, while WAF is installed inline at the perimeter of the network in layer 3.

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