IDS vs IPS: What are the major differences?

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Imagine you are walking on a straight path, and it slowly diverges into two. One way is guarded by a silent observer, an Intrusion Detection System (IDS), which keenly watches every step you take, ready to alert you at the slightest hint of danger. The other path is patrolled by an assertive knight, the Intrusion Prevention System (IPS), armed and vigilant, prepared to fend off threats before they harm you.

In cybersecurity, these are the two primary protectors of your networks. IPS and IDS are two essential components of cybersecurity, working tirelessly to protect your data and systems from cyber-attacks. But what sets them apart? Are they interchangeable, or do they serve distinct purposes? This article will dive into the major differences between IDS and IPS, shedding light on their unique roles and functionalities.

What are the Key Differences between IDS and IPS?

Feature IDS IPS
Detection Passive Active
Detection Methods Signature-based detection Signature-based detection and Anomaly-based detection
Prevention No Yes
False Positives More likely Less likely
Response Gives alerts Blocks or prevents attacks
Impact on network performance Less impact More impact
Scope Network-wide Specific network segments or hosts
Location Inside the network At the network perimeter or critical points within the network


IDS doesn’t actively participate in network traffic; it monitors traffic and analyses it for suspicious patterns. IPS actively probes the traffic and can send out requests to gather additional information. This allows IPS to detect more sophisticated attacks that are not apparent from passive monitoring alone.

Detection Methods

Both IDS and IPS can use signature-based detection to identify known attacks. This method involves comparing network traffic to a database of known attack signatures. If a match is found, the system generates an alert. IPS can also use anomaly-based detection to identify unknown attacks. This method involves analysing network traffic for patterns that deviate from normal behaviour. If an anomaly is detected, the cybersecurity system generates an alert.


IDS cannot prevent attacks on its own. It can only generate alerts that notify security personnel of potential threats. IPS can take steps to prevent attacks from occurring. It can block malicious traffic, reset connections, or take other actions to stop an attack in progress.

False Positives

IDS is more likely to generate false positives because it relies on patterns and signatures to detect attacks, and these patterns can sometimes match benign traffic. IPS is less likely to cause false positives because it can actively probe network traffic and gather additional information. This allows it to identify malicious traffic more accurately.


IDS generates alerts when it detects suspicious activity. These alerts are typically sent to a security console or SIEM system for analysis. IPS can take immediate action to block or prevent attacks. This can help to prevent damage to systems and data.

Impact on network performance

IDS has a minimal impact on network performance as it does not actively participate in network traffic. IPS can impact network performance because it actively probes network traffic and takes steps to block or prevent attacks.


IDS monitors network traffic across the entire network and compares network packets against known threats using the signatures or a baseline created using machine learning. IPS monitors specific network segments or hosts and either accepts or rejects network packets based on the preset rules. This is useful for protecting critical systems or applications.


IDS sensors are typically deployed inside the network, where they can monitor traffic between internal hosts and devices. IPS sensors can be deployed at the network perimeter to block attacks before they reach the internal network. They can also be deployed at critical points within the network to protect specific systems or applications.

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What is an Intrusion Detection System (IDS)?

An Intrusion Detection System is a passive network security solution that monitors network traffic for any signs of unauthorised access or suspicious activity. The primary role of an IDS is to monitor network traffic and identify potential security threats. An IDS analyses packet data and compares it against pre-defined signatures and security policies.

These signatures and policies are reference points for determining whether a network event is benign or a potential intrusion. A signature-based IDS can easily detect new threats and attacks. When it detects an intrusion, it sends an alert to the security team, allowing them to take appropriate action. This action can range from further investigation to implementing preventive measures to intercept the intrusion.

There are five types of IDS. They are:

  1. Network Intrusion Detection System (NIDS): A NIDS monitors network traffic for suspicious activity, such as unauthorised access attempts, port scans, and malware infections. 
  2. Host Intrusion Detection System (HIDS): A HIDS monitors the activity of individual hosts on the network, looking for signs of malicious behaviour, such as unauthorised file modifications, suspicious system calls, and changes to system configurations.

  3. Protocol-Based Intrusion Detection System (PIDS): A PIDS monitors specific network protocols, such as TCP/IP, for deviations from normal behaviour. PIDS sensors are typically deployed at the network perimeter to monitor incoming and outgoing traffic.

  4. Application Protocol-Based Intrusion Detection System (APIDS): An APIDS monitors specific application protocols, such as HTTP, FTP, and SMTP, for suspicious activity. 

  5. Hybrid Intrusion Detection System (HIDS): A hybrid IDS combines multiple types of IDS, such as NIDS, HIDS, and PIDS, to provide more comprehensive coverage. It can give a more accurate view of network security by correlating data from multiple sources.

What is an Intrusion Prevention System (IPS)?

An Intrusion Prevention System (IPS) takes network security to the next level. While an IDS is passive and primarily focuses on alerting, an IPS is an active security solution designed to detect intrusions and prevent them from happening in the first place. It sits behind the firewall and is a robust barrier that actively blocks suspicious or malicious activities, effectively blocking potential threats.

An IPS system uses similar methods as an IDS, such as signature-based detection, anomaly detection, and heuristic analysis. It works by actively monitoring network traffic, analysing it for signs of unauthorised access or malicious activity, and taking real-time action to prevent potential threats. This proactive approach helps protect networks and systems from various cyber threats and vulnerabilities.

There are four types of IPS. They are:

  1. Network-based IPS (NIPS): A NIPS monitors and analyses network traffic for suspicious activity, similar to a network intrusion detection system (NIDS).

  2. Wireless IPS (WIPS): A WIPS monitors and analyses wireless network traffic for suspicious activity. It can detect attacks such as unauthorised access attempts, rogue access points, and malware infections. 

  3. Network behaviour analysis (NBA): An NBA system analyses network traffic to identify patterns that deviate from normal behaviour. This can help detect attacks not known to the IPS, such as zero-day attacks. 

  4. Host-based IPS (HIPS): A HIPS monitors the activity of individual hosts on the network, similar to a host intrusion detection system (HIDS). However, instead of just generating alerts, it can take action to block or prevent attacks on the host. 

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What are the Similarities between IDS and IPS?

Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS) share several similarities in functionality and purpose.

  1. Both IDS and IPS are designed to protect computer networks from unauthorised access, malicious activities, and security threats.
  2. They both work by monitoring network traffic and analysing it for signs of potential security breaches.
  3. Both systems use pre-defined attack signatures and behavioural analysis to detect and prevent intrusions.
  4. IDS and IPS can alert network administrators in real-time when suspicious activity is detected, allowing immediate action to mitigate potential threats.

Benefits of IDS and IPS

  1. IDS and IPS can provide detailed insights into network traffic patterns, helping to identify suspicious activity and potential threats early on before they can cause significant damage.
  2. Both can be configured to detect and block known attack signatures, preventing these attacks from reaching and exploiting vulnerabilities on the network.
  3. They can help prevent data breaches by blocking malicious traffic attempting to steal or exfiltrate sensitive data.

Limitations of IPS and IDS

  1. IDS and IPS can sometimes generate false positives, alerts that indicate a potential attack when there is no threat.
  2. They can only monitor the traffic they can see, which means that they may not be able to detect attacks from outside the network perimeter or use encryption to hide their activity.
  3. They can be resource-intensive, especially in large or complex networks, which impacts network performance and may require additional hardware or software to support the deployment of these systems.

How do IDS and IPS work together?

While IDS and IPS solutions have different functions, they can work together to enhance network security. They complement each other in network security. An IDS provides valuable insights and alerts about potential threats, while an IPS takes immediate action to prevent those threats from causing harm. Together, they create a more robust security posture for organisations.

Integrating IDS and IPS solutions offers several advantages. Firstly, it simplifies the security infrastructure by combining intrusion detection and prevention systems into a single system. This reduces complexity and makes it easier to manage and maintain. Integrating IDS and IPS allows for a faster and more efficient response to security incidents, as both detection and prevention can be automated.

Also Read:

IDS vs IPS: Which detection method is better for you?

When to consider implementing an IDS?

If your primary goal is to gain deeper insights into network activity and identify suspicious behaviour, an IDS is a suitable choice. It provides passive monitoring and alerts you to potential threats, allowing you to investigate further. IDS might be better if you have a limited budget or security personnel, as it requires less configuration and ongoing maintenance than an IPS.

When to consider implementing an IPS?

If you want to block or prevent attacks in real-time actively, an IPS is the right choice. It immediately stops malicious traffic, preventing damage or data breaches. If you have a network frequently targeted by IP address-based attacks, such as denial-of-service (DoS) attacks or botnet attacks, you should consider implementing an IPS.

When should you use both IDS and IPS together?

Using IDS and IPS creates a comprehensive security strategy for networks with high-value assets or critical infrastructure. These two systems work together to create a strong security posture. IDS can detect and alert, while IPS can block, and other security measures, such as firewalls and endpoint security, can further strengthen the defence. If your network has a wide range of traffic types and protocols, using IDS and IPS can ensure comprehensive coverage.

Also read: ACSC Essential 8 Strategies For Cyber Security: A Comprehensive Guide


In the complex world of network security, the choice between an Intrusion Detection System (IDS) and an Intrusion Prevention System (IPS) often simply boils down to your specific needs and objectives. The choice between IDS and IPS is crucial in today’s ever-evolving digital landscape. We encourage you to assess your network’s specific needs and vulnerabilities.

Are you more inclined towards a vigilant observer or a proactive protector? Understanding the strengths of each system will enable you to make informed decisions that best suit your cybersecurity strategy.

So, what’s your next move? Whether you’re considering the vigilant observer, the proactive protector, or a combination of both, our experts at Binary IT will provide insights and solutions to ensure your network remains safeguarded. Contact us today to discuss your network security goals.

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