The power of IDS technology lies in its usefulness as a security tool. IDSes can be used to complement firewalling strategies, serve as another layer of defense or augment a security team's efforts. More customizable products, such as Cisco Systems' NetRanger and Network Flight Recorder's NFR Intrusion Detection Appliance, also can be used to protect specified data. NetRanger and ISS RealSecure are mature offerings; RealSecure is the more polished of the two. One caveat: Organizations looking at IDS technology should thoroughly examine their requirements because the feature ranges of these products vary greatly.

An IDS, like any single security product, should not be seen as an end-all security tool. If your organization hasn't addressed audit, policy and architectural design issues, your time and money may be more well-spent hammering out those areas before investing in an IDS.