Which of these is NOT a type of intrusion detection system (IDS)?

Which of these is NOT a type of intrusion detection system (IDS)?

• Behavior-based
• Host-based
• Tunnel-based
• Network-based 

EXPLANATION

Behavior-based IDS looks for variations in behavior, like unusually high traffic, policy violations,
things like that. Deviations in behavior help it recognize potential threats. A network-based IDS examines all network traffic going to and from network systems. A host-based IDS refers to applications like spyware or virus applications that are installed on individual network systems and monitor for things like system file modifications or registry changes.