Demystifying NAC

Despite the security benefits promised by network access control, NAC has yet to be fully embraced. Perhaps it’s the perceived cost, the complexities that troubled early adopters or the plethora of NAC choices available today.

That’s not to say there isn’t enormous interest. After all, a NAC security framework promises to help companies comply with regulations and internal policies, and safeguard resources from evolving threats.

But which approach is best?

Hardware-based options typically require an appliance that operates either in-line or out-of-band. Some of these appliances displace the access switch; others operate between the access layer and network switches. With either approach, there are many deployment, management and operational considerations.

For example, hardware-based in-line NAC solutions that sit upstream from switches create a potential single point of failure and can be disruptive if they cannot maintain pace with today’s high-speed, 10G network backbones.

Furthermore, in-line NAC solutions may not be ideal for geographically dispersed or highly segmented networks. Not only does there need to be an appliance at every location, but the further up the network the less visibility into network traffic these approaches provide. There’s little sense believing you’re more secure with NAC when you can’t see or stop an intruder’s traffic on a large subnet.

The out-of-band alternative, such as the options that use 802.1x, too often require many network and server configuration changes. They require additional quarantine networks, configuration of ports on each switch as well as access rules to be configured for routers and switches. This not only increases administrative costs, it also increases the risk of error. Clearly, hardware-based NAC isn’t cheap or a panacea.

Next up is the much maligned agent-based approach. No one wants yet another endpoint application to install, update and maintain. It’s not only an additional burden for the IT team but also another catalyst for flurries of help desk calls.