Open source NAC communities have two key advantages of all open source communities, says Russell Yount, the network architect at Carnegie Mellon University in Pittsburgh: It finds bugs quickly and expands features as demand for them arises. Carnegie Mellon has its own NAC software called NetReg designed for use specifically at the school, but it is flexible enough to be used at Worcester Polytechnic Institute, Duke University, the University of Alabama and Woods Hole Oceanographic Institute among others, Yount says.
Flexibility is important because being customized for a particular environment restricts usefulness. For instance, Rings, the NAC software written at the University of Kansas for use on campus, is customized for its homegrown DHCP servers, so its DHCP enforcement isn't widely applicable outside the campus, says Dustin Brown, the lead developer and designer of Rings.
Rings ties a username to a MAC address to register machines to the network that also sends a Java agent to the client machine to check for antivirus software and install it if it's not there. It also configures machines to tap the local update server, and assures their IP address falls within the appropriate range and that they have the most critical Windows updates.
Rings uses DHCP to isolate machines, and the fact that University of Kansas uses its own version of DHCP is a limiting factor for use of Rings, he says.
"I think that's the biggest stumbling block that other groups are having, that they don't want to redo their entire DHCP infrastructure just to get NAC. They'd much rather use what they already have," Brown says.
That doesn't prevent others from using Rings, though. For instance, Trinity Christian College in Palos Heights, Ill., had to delay deploying Rings while it made needed changes, says Kevin Jacobs, coordinator of computer services at the school.
The school tried to integrate Rings' DHCP back end with Microsoft Active Directory as part of the NAC policy platform, but that proved difficult. "We spent a lot of time working on this and decided we wouldn't be able to get it working in time for students arriving on campus [in the fall of 2005]," says Jacobs. Ultimately that required code changes to the DHCP used by Rings, a process that was aided by Brown at the University of Kansas. "Dustin helped guide us through a lot of configuration," he says.
This cooperation is typical of the open source NAC effort, says Williams College's Berman, and is being borne out by interactions among the groups. For instance, FreeNAC's Boran wants to share information with PacketFence. "We're more than willing to work with anyone that's interested," says Amorin.
"There's not a lot of overlap in the way we do things in our platforms," says LaPorte, " so we may both be able to pick up a lot of things."
Still, it may be some time before open source NAC takes hold in enterprises, says Forrester's Whitely. Businesses switch to open source platforms when they are stable and integrate easily with all networks, and even then it takes concerted effort. The same will hold true with NAC.
"It will take a champion of some kind for this to make the leap to enterprises," Whiteley says.