New firewalls defend the interior

The firewall, which has served as the sentry between the outside world of the Internet and the internal agency network, may be moving inside the network perimeter to World Wide Web servers, PCs, modems and silicon chips.

Such internal firewalls — known as distributed firewalls — are the next line of defense against hackers who breach traditional firewalls by exploiting open ports and e-mail servers.

Network managers tend to see distributed firewalls as added firepower against hackers.

"It's a dual protection," said Rick Shantery, senior network engineer at Intellinetics Corp., a document management firm in Columbus, Ohio. He added CyberWallPlus embedded firewall software, a product from Network-1 Security Solutions Inc., to his internal servers after he realized that hackers occasionally made it past Ramp Networks' WebRamp Internet access and firewall box Intellinetics uses.

"I could see from the log data they were coming in," he said. "These deliberate hack attacks happen daily, [but] if they make it through, the embedded firewall in the server is there to stop them."

The second line of defense may also be necessary because traditional firewalls do little to stop inside attacks, according to top firewall expert Steven Bellovin, an AT&T Corp. Labs researcher.

"Distributed firewalls can reduce the threat of actual attacks by insiders, simply by making it easier to set up smaller groups of users," Bellovin wrote in the paper "Distributed Firewalls." "Thus, one can restrict access to a file server to only those who need it, rather than letting anyone inside the company pound on it."

But some security vendors have mixed views about distributed firewalls.

Mark McArdle, a vice president in Network Associates Inc.'s managed security services division, questioned the value of running firewall software directly on the Web server.

"Applications on servers are usually managed by different people than the ones who manage firewalls," McArdle said. "Application servers tend to be changed with a little more of a cavalier attitude, which could affect the firewall on it."

John Pescatore, research director for network security at the Gartner Group Inc. consultancy, concurred.

"The problem is the Webmasters control the Web server," Pescatore said, noting that when they make wholesale changes, it could destroy the efficacy of the firewall software on it.

Rather, Pescatore is bullish on the idea of embedding firewalls in silicon, something that Secure Computing Corp. is undertaking with 3Com Corp., and WatchGuard is trying to do by licensing its Firechip. Hardware will support faster packet processing than software, he said.

For more information about enterprise networking, go to Network World Fusion. Story copyright 2000 Network World Inc. All rights reserved.


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