I was reading a NAC post by Alan Shimel (gee, what a shock), and it brought up one of my pet peeves about NAC. Now I will fully admit that NAC isn’t an area I spend nearly as much time on as data and application security, but I still consider it one of our more fundamental security technologies that’s gotten a bad rap for the wrong reasons, and will eventually be widely deployed.

The last time I talked about NAC in detail I focused on why it came to exist in the first place. Basically, we had no way to control what systems were connecting to our network, or monitor/verify the health of those systems. We, of course, also want to control which users end up on our network, and there’s been growing recognition for many years now that we need to do that lower on the OSI stack to protect ourselves from various kinds of attacks. Here’s how I’ve always seen it:

  1. We use 802.1x to authenticate which users we want to allow to connect to our network.
  2. We use NAC to decide which systems we want to allow to connect to our network.

I realize 802.1x is often ‘confused’ with NAC, but it’s a separate technology that happens to complement NAC. Alan puts it well:

  1. Authentication is where we screwed up. Who said NAC was about authentication? Listening yesterday you would think that 802.1x authentication was a direct result of NAC needing a secure authentication process. Guys lets not put the cart in front of the horse. 802.1x offers a lot of other features and advantages besides NAC authentication. In fact it is the other way around. NAC vendors adopted 802.1x because it offered some distinct advantages. It was widespread in wireless networks. However, JJ is right. It is complex. There are a lot of moving parts. If you have not done everything right to implement 802.1x on your network, don’t bother trying to use it for NAC. But if you had, it does work like a charm. As I have said before it is not for the faint of heart.

Hopefully JJ and Alan won’t take too much umbrage from this post, but when looking at NAC I suggest to keeping your goals in mind, as well as an understanding of NAC’s relationship with 802.1x. The two are not the same thing, and you can implement either without the other.