Network Associates said it has entered into an agreement to purchase IntruVert Networks for $100 million in cash, an acquisition that will give NAI a line of products as well as underlying technology for intrusion prevention.

The deal, expected to be approved by regulatory authorities in about 45 days, will bring privately held IntruVert, which makes the IntruShield 4000 and IntruShield 2600 appliances, into the NAI fold. It also puts a nail in the coffin of the strategic technology relationship that began last May between NAI and Internet Security Systems.

At that time, NAI executives said the company intended to add ISS intrusion-detection technology to NAI's high-speed Sniffer traffic-analysis product by mid-year. But slow progress raised doubts about the effort, and NAI executives a month ago acknowledged they were looking at alternatives.

This week, it's IntruVert in and ISS out.

"We will not move forward with ISS in Sniffer," said Sandra England, NAI executive vice president of corporate development and strategic research. She added that she sees "no real application for [the ISS] technology in our portfolio going forward."

IntruVert's technology focus is on intrusion-prevention, which entails not just detecting attacks, but blocking them. The IntruVert product line can be used as a passive intrusion-detection system, just watching and reporting, or it can be used in the intrusion-prevention mode of blocking a perceived attack.

IntruVert competes against Enterasys Networks, ISS, Intrusion Inc., NetScreen, TippingPoint, and Recourse Technologies, which was just bought by NAI archrival Symantec.

Corporate interest in using intrusion-prevention systems (IPS) is growing as these in-line products improve their speed, accuracy and fail-over capabilities, but many network managers are still reluctant to actively block traffic, concerned that legitimate traffic may be blocked by mistake.

While NAI is not going forward with the plans to add ISS intrusion detection to Sniffer, it may look at adding IntruVert's intrusion-prevention capabilities to Sniffer, though not by mid-year.

"We felt that in order to fulfill our vision to our customers, we need to own the technology," says England. "And we feel the market is moving from intrusion detection to prevention."