What is the difference between IDS and IPS in modern Next-Generation Firewalls?

All answers to this question.

In modern environments, most organizations run IPS in "prevention" mode for known, high-confidence signatures to stop common attacks instantly. However, "detect-only" (IDS) is still used for new or sensitive rules where the risk of a "false positive" could shut down a critical business application. If you block legitimate traffic (like a database sync) because it "looked" like an attack, the downtime cost can be higher than the security risk. Usually, you start a new rule in IDS mode for a week to baseline it, and once you're sure it's accurate, you flip the switch to IPS mode.

   Answered 2025-02-17 by Heather Williams

Have you looked into how encrypted traffic (HTTPS) affects the ability of your IDS/IPS to actually see the payloads without an SSL inspection proxy?

   Answered 2025-02-19 by Christopher Evans

• SSL decryption is the "hidden cost" of modern IPS. Without it, your firewall is essentially blind to over 90% of web traffic. However, decrypting traffic requires serious hardware resources and raises privacy concerns. You have to balance the need for deep packet inspection with the latency it introduces to the network. It's one of the biggest challenges for network admins today.

     Commented 2025-02-22 by Michael Scott

Automation is the key. Modern systems can trigger a block in the firewall based on an IDS alert automatically, effectively making it a "reactive" IPS.

   Answered 2025-02-24 by Linda Martinez

• Agreed, Linda. This "active response" setup gives you the best of both worlds—manual oversight where needed and instant blocking for obvious malicious patterns.

     Commented 2025-02-26 by Robert Collins