Understanding the Role of IPS and IDS in Network Security

network security

With networks becoming more connected than ever before–with mobile devices and work-from-home on a massive scale–vigilance is essential. That’s why IPS and IDS are critical tools to protect your network.

When a threat is detected, an IPS immediately stops it from spreading. This can include closing sessions, blocking IP addresses, or other steps.

Security Policy Management

Many still need clarification about where does IPS vs IDS fit in the network.  In a network architecture, IPS are strategically placed at key entry points or critical junctures to actively block and thwart malicious activities in real-time, serving as a proactive defense mechanism. In contrast, IDS are often deployed throughout the network to monitor and analyze traffic passively, identifying potential threats and providing alerts without intervening, making them valuable for comprehensive threat detection and incident response.

IPSs use threat-specific detection techniques to identify and stop cyberattacks such as phishing, malware infection and distribution, virus attacks, SQL injection, man-in-the-middle attacks, denial of service (DoS), data breaches, and zero-day exploits. Unlike IDS, which merely raises an alarm to an attack in progress, IPS takes action to halt or block the activity before it can do much damage.

Depending on the type of IPS you deploy, it may either scan for known threats and their signatures or look for anomalies in network traffic and behavior that can be detected by monitoring multiple sensor points in real time. Some IPSs are also infused with artificial intelligence and machine learning to spot and block various threats more quickly than if they were monitored manually.

Once an IPS detects a threat, it typically closes the session that caused the anomaly and stops it from doing further damage by closing connections, shutting down ports or IP addresses, or blocking entire networks. IPSs can even take steps to strengthen firewalls that have been breached.

Other IPSs monitor specific network parts, such as a wireless IPS that monitors only the organization’s owned and managed wireless networks. This helps reduce the strain on IT teams that might otherwise be needed to monitor and respond to every alert. Many IPS solutions are also available in bypass mode or “tap mode” for organizations that want to build confidence with the technology before switching it on inline.

Detection and Response

Both IPS and IDS monitor network traffic to spot cyberattacks and alert administrators. An IPS takes the next step, however, by stopping threats without the input of a human administrator.

IPS solutions use multiple detection methods to watch all network packets traveling and compare them against a constantly updated threat profile with new information. If a device detects a suspicious activity, it generates an alarm and records that activity in a database for later analysis. An IPS solution can also create summary alerts when the same signature triggers several times, reducing individual notifications.

An IPS can also respond to detected attacks by terminating the offending source and resetting connections if required. It can even reprogram other infrastructure devices, such as firewalls, to prevent future attacks, and all activity is logged for future review.

IDS and IPS are best placed in critical segments of your network, where they can spot threats that might not reach the firewall or antivirus software. These systems perform in real-time, but it’s essential to ensure they are appropriately configured to avoid false positives. This can help you improve your security posture and comply with regulatory requirements. In addition, the logs generated by these systems can be used to investigate breaches and prosecute attackers. In some jurisdictions, IPS and IDS data may be admissible as evidence that your organization did everything possible to thwart the attack.

Network Traffic Analysis

Unlike IDS, which detects and alerts on threats but does not intervene with them, an IPS takes action. It can prevent an attack in progress by taking automated actions such as terminating a user session or changing firewall rules to block a cyberattack before it can cause harm. It also can scrub suspicious data from network traffic and even reset connections to halt the attack. It can log these activities and notify security staff of the threat.

The IPS’s ability to take real-time action helps it reduce the dwell time of bad actors by cutting off their access to critical assets and systems. It also cuts down on false alerts, which can overwhelm security teams and slow the overall reaction to a breach.

Most IPSs use signature-based detection, which examines current and historical network activity to find recognizable patterns or markers to identify an attack. These are known as signatures, and once the system spots a match, it triggers an alarm or blocks the traffic. This approach can be practical, but attackers constantly update their attack methods to evade detection.

Increasingly, IPSs are using anomaly-based detection. These systems create a behavioral model of regular network activity and then look at all future traffic to spot anything that is not usual. They can be more effective than traditional IPSs and may catch zero-day attacks but produce more false positives.


When an attack is detected, IPS systems immediately take action. They may stop traffic, close ports, or block specific connections to prevent attackers from moving around the network. They’re also designed to keep you in the loop and alert you when a threat happens so that you can investigate and decide whether to let those floodgates back up or not.

Like firewalls, IPS devices have logging capabilities that capture the activity they see. This data can be retrieved later to analyze the attack and determine what steps it took or how it progressed. These logging abilities help eliminate false positives where the system thinks an attack is taking place but is not. This kind of false detection can degrade system performance and usability.

IDS and IPS have signature-based detection that looks for preconfigured and predetermined attack patterns, known as signatures. Attackers constantly change their methods, so these detection techniques must be updated regularly to mitigate new threats.

Because of its inline nature, IPS can react quickly to an attack by dropping suspect packets or redirecting them away from suspicious sources. It can also reset connections and reprogram other infrastructure devices, such as routers or firewalls, to block network traffic (also referred to as shunning) from the suspicious source. This can be performed either automatically or by a network security administrator. Many IPS systems also offer an out-of-band bypass mode, such as Ixia’s iBypass, which allows you to monitor and get up-to-speed with the system before deploying it inline.