Network traffic is monitored by the IPS, which analyzes it for threats. If no threat is found, traffic passes. If a threat is detected, the IPS blocks or alerts and logs the event.
Execution Sample
Cybersecurity
1. Traffic packet arrives
2. IPS inspects packet
3. Check if packet matches threat
4. If threat, block and alert
5. Else, allow packet
This sequence shows how an IPS processes each network packet to decide if it should be blocked or allowed.
Analysis Table
Step
Traffic Packet
Threat Detected?
Action Taken
Output
1
Packet A (normal web request)
No
Allow
Packet passes to destination
2
Packet B (malicious payload)
Yes
Block and Alert
Packet blocked, admin notified
3
Packet C (normal email)
No
Allow
Packet passes to destination
4
Packet D (known attack signature)
Yes
Block and Alert
Packet blocked, admin notified
5
Packet E (normal file transfer)
No
Allow
Packet passes to destination
6
End of traffic stream
-
-
IPS stops processing
💡 No more packets to inspect, IPS finishes monitoring.
State Tracker
Variable
Start
After 1
After 2
After 3
After 4
After 5
Final
Traffic Packet
None
Packet A
Packet B
Packet C
Packet D
Packet E
None
Threat Detected
False
False
True
False
True
False
N/A
Action Taken
None
Allow
Block and Alert
Allow
Block and Alert
Allow
N/A
Output
None
Pass
Blocked
Pass
Blocked
Pass
End
Key Insights - 3 Insights
Why does the IPS allow some packets and block others?
The IPS checks each packet for known threat patterns. If no threat is detected (see rows 1,3,5 in execution_table), it allows the packet. If a threat is detected (rows 2,4), it blocks and alerts.
What happens if the IPS misses a threat?
If the IPS does not detect a threat in a malicious packet, it will mistakenly allow it. This is why IPS rules and signatures must be updated regularly to catch new threats.
Does the IPS stop monitoring after blocking a threat?
No, the IPS continues to monitor all incoming traffic until there are no more packets (see final step in execution_table). Blocking one packet does not stop the system.
Visual Quiz - 3 Questions
Test your understanding
Look at the execution table, what action is taken at step 4?
AAllow the packet
BIgnore the packet
CBlock and alert
DLog only
💡 Hint
Check the 'Action Taken' column at step 4 in the execution_table.
At which step does the IPS detect a threat for the first time?
AStep 2
BStep 1
CStep 3
DStep 5
💡 Hint
Look at the 'Threat Detected?' column in the execution_table to find the first 'Yes'.
If Packet C was malicious but not detected, how would the 'Action Taken' at step 3 change?
AIt would change to 'Ignore'
BIt would remain 'Allow'
CIt would change to 'Block and Alert'
DIt would change to 'Log only'
💡 Hint
Refer to variable_tracker for 'Threat Detected' and 'Action Taken' at step 3.
Concept Snapshot
Intrusion Prevention Systems (IPS) monitor network traffic in real-time.
They analyze each packet for known threats using signatures or rules.
If a threat is detected, IPS blocks the packet and alerts administrators.
Safe packets are allowed to pass through.
IPS continuously monitors traffic without stopping after blocking threats.
Regular updates keep IPS effective against new attacks.
Full Transcript
Intrusion Prevention Systems (IPS) work by monitoring network traffic as it arrives. Each packet is inspected to see if it matches known threat patterns. If no threat is found, the packet is allowed to continue to its destination. If a threat is detected, the IPS blocks the packet and sends an alert to the system administrator. This process repeats for every packet until there is no more traffic to inspect. The IPS does not stop after blocking a threat; it keeps monitoring continuously. This helps protect networks from attacks by stopping harmful traffic before it reaches devices. Regular updates to the IPS rules are important to catch new threats that appear over time.