Cisco® Secure Internet Security Solutions

Frequently Asked Questions

Question:	What is intrusion detection?
Answer:	Intrusion detection is the passive monitoring of the traffic flow on a network segment to detect any suspicious activity on the network. Once a problem is identified, an intrusion detection system can take action against the session to ensure that it is not maintained.
Question:	I already have a firewall; why do I need intrusion detection as well?
Answer:	A firewall is a device that can protect internal networks from external threats by providing address translation and stateful inspection of traffic flow. The firewall does not have the intelligence by default to know whether the packet flow through the firewall represents genuine traffic or an attempted attack that is hiding ...