In IB Computer Science, students learn that network security requires more than simply blocking traffic or monitoring activity. This is where Intrusion Prevention Systems (IPS) come in. An IPS builds on the ideas behind firewalls and intrusion detection systems by actively stopping attacks in real time.
IB examiners expect students to understand what an IPS does, how it differs from IDS, and why prevention matters.
What Is an Intrusion Prevention System (IPS)?
An Intrusion Prevention System (IPS) is a security system that:
- Monitors network or system activity
- Detects malicious behaviour
- Automatically blocks or stops attacks
Unlike an IDS, which only detects and alerts, an IPS takes direct action when a threat is identified.
In IB terms, an IPS focuses on real-time threat prevention.
How an IPS Works (Conceptually)
An IPS works by:
- Monitoring network traffic or system activity
- Comparing activity to known attack patterns or abnormal behaviour
- Identifying potential threats
- Blocking, rejecting, or terminating suspicious traffic
IB students are not expected to know implementation details, only the logical sequence.
IPS vs IDS: The Key Difference
A common IB comparison:
- IDS
- Detects suspicious activity
- Generates alerts
- Requires human response
- IPS
- Detects suspicious activity
- Automatically blocks attacks
- Acts without human intervention
The core distinction is:
- IDS = detection
- IPS = detection and prevention
IPS vs Firewalls
While firewalls and IPS both block traffic, they work differently.
- Firewalls
- Use predefined rules
- Control access based on source, destination, or port
- Focus on permitted connections
- IPS
- Analyses behaviour and patterns
- Detects attacks that appear within allowed traffic
- Stops malicious activity dynamically
IPS systems provide deeper inspection than basic firewalls.
Why IPS Are Important
IPS are important because:
- Some attacks bypass firewalls
- Attacks can occur within allowed connections
- Speed matters in preventing damage
By responding immediately, an IPS can:
- Prevent data breaches
- Stop malware spread
- Reduce system downtime
IB students should link IPS use to damage prevention.
Limitations of IPS
Despite their benefits, IPS systems have limitations.
These include:
- False positives blocking legitimate traffic
- Performance overhead
- Need for regular updates
IB examiners often reward answers that mention trade-offs.
IPS in Real-World Systems
IPS are commonly used in:
- Enterprise networks
- Data centres
- Cloud environments
They are part of a layered security strategy, not a standalone solution.
IPS and Defence in Depth
IPS contribute to defence in depth by:
- Adding an active response layer
- Complementing firewalls and IDS
- Reducing reliance on manual intervention
Layered security reduces the chance of a single failure causing major damage.
Common Student Mistakes
Students often:
- Say IPS only detect attacks
- Confuse IPS with firewalls
- Ignore false positives
- Forget automation
Clear functional explanations score higher.
How This Appears in IB Exams
IB questions may ask students to:
- Explain what an IPS does
- Compare IPS with IDS or firewalls
- Justify IPS use in a scenario
- Discuss benefits and limitations
Comparison and justification earn marks.
Final Thoughts
An Intrusion Prevention System monitors activity, detects threats, and automatically blocks attacks in real time. By combining detection with prevention, IPS systems reduce the damage caused by cyberattacks and strengthen network security.
Understanding how IPS work allows IB Computer Science students to explain modern, proactive security strategies clearly and confidently — exactly what examiners expect.
