Intrusion-prevention system is the new buzzword this week. A combination of intrusion-detection brains and firewall placement, IPSes take a new tack on protecting corporate networks. The concept is simple: When intrusion detection notices a problem, intrusion prevention blocks the bad traffic.

The implementation is a lot more difficult. As Network World showed in this year's review of intrusion-detection systems (IDS), vendors haven't figured out enterprise-level management of IDSs. Avoiding false alarms requires tuning the IPS within an inch of its life, or using a much less comprehensive rule set than the IDS world supports.

In the meantime, firewall vendors have been quietly adding IPS features to their products. Cisco has integrated technology from its Wheel Group acquisition into PIX and IOS; NetScreen already had quite a few IPS features (and probably will be adding more since it acquired IPS vendor OneSecure); and Check Point Software has built the SmartDefense system into newer versions of its Firewall-1 NG product. It's not just firewall vendors that are getting into the act. Switch and load-balancing company TopLayer Networks is adding IPS features to its product line as well.

Despite this handful of firewall manufacturers getting involved in IPS, the overall sector has been asleep at the switch, content to sit on market share and drive the idea of stateful packet filters as far as they can go. The interest in IPS is good because it will get more firewall and switch developers to start thinking again about new tools to help keep networks secure at the core and edge.

So what does this mean for network managers? IPS technology is just that: a technology. It's not a product. An IPS has to go into core network choke points to be effective. While the idea of a "pure" IPS product might appeal to vendors looking to capitalize on the current mania for security, it's not a long-term bet.

Instead, you're going to see the folks who are already at the core of your network - the firewall vendors, switch vendors, load balancers and such - using IPS technology to improve their products. A good IPS combines the long-standing intelligence of high-speed switching and firewalling with the new thinking from the IDS world.