Designing Access Controls

Select an EAP Method for 802.1X

4.Are you using IDM and is the NAC 800 proxying requests to another RADIUS server?

If not, the default access method should be EAP-TTLS. EAP-TTLS and PEAP are similar in terms of architecture and security, but EAP-TTLS allows a greater variety of authentication methods to be tunneled and thus provides greater flexibility.

However, EAP-TTLS and some implementations of PEAP might conceal a user’s username. Typically, this is not a problem; in fact it increases security. However, if you are using IDM and a NAC 800 for endpoint integrity and the NAC 800 proxies requests to another RADIUS server, you must ensure that the proxy RADIUS server uses the Windows imple- mentation of PEAP. Otherwise, the IDM agent on the NAC 800 cannot detect a user’s name and assign the correct dynamic settings.

In the PCU example, the university does not have a full PKI system—finding it too expensive and too difficult to implement with the large numbers of students who leave and enter each year. Given that most endpoints run Windows and that you do not want to force students to purchase a vendor utility, you stop the decision at step 2 and choose PEAP with MS-CHAP.

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