What does IPS stand for?
IPS stands for Intrusion Prevention System. A system placed inline that inspects traffic and blocks attacks in real time. It is active, so a false positive can block legitimate traffic.
An IPS does what an IDS does and then acts: it sits inline, so traffic passes through it, and it can drop packets, reset connections or block a source. That makes placement and tuning matter more. A false positive on an IPS blocks legitimate traffic, and a failed inline device can take the link down unless it is set to fail open.
IPS in practice: an example
An IPS in front of a web farm recognizes an SQL injection attempt in a request and drops it before it reaches the server. The same week a badly tuned rule blocks a partner's file upload, and the team moves that rule to alert-only until it is fixed.
What IPS is confused with
IPS vs IDS: what is the difference?
Same detection, different position. The IDS watches a copy and alerts; the IPS is in the path and blocks. What IDS stands for
IPS vs WAF: what is the difference?
An IPS covers many protocols at the network level. A WAF understands HTTP in depth and protects web applications specifically. What WAF stands for
IPS vs in-plane switching: what is the difference?
On the A+ acronym list IPS means in-plane switching, a type of LCD panel with wide viewing angles. In a hardware or display question that is the meaning intended; in a security or network question it is the intrusion prevention system.
Which exams cover IPS?
IPS is on the official CompTIA acronym list for three of the four exams covered here.
- Security+ SY0-801: 4.1 (Security Operations).
- CySA+ CS0-004: on the acronym list, not tied to one objective.
- Network+ N10-009: 1.0 (Networking Concepts).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. After an IPS is installed, a business application stops working although no attack is under way. What is the most likely cause?
- A false positive is blocking legitimate traffic
- The IPS has no IP address
- The switch needs more VLANs
- DNS records have expired
Show the answer
A. A false positive is blocking legitimate traffic. Because an IPS is inline, a wrong detection stops real traffic. The fix is to tune or disable the offending rule.
2. Which requirement points to an IPS instead of an IDS?
- Keep a record of suspicious traffic
- Stop a known exploit before it reaches the server
- Monitor a mirrored port
- Avoid any change to the traffic path
Show the answer
B. Stop a known exploit before it reaches the server. Only an inline device can stop traffic. Recording and mirrored-port monitoring describe an IDS.
Sources: NIST glossary: intrusion prevention system; NIST SP 800-94, Guide to Intrusion Detection and Prevention Systems. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.