3Com 8760 User Guide - Page 50

CHAPTER 4: SYSTEM CONFIGURATION use both MAC address and 802.1X authentication, with client station MAC authentication occurring prior to IEEE 802.1X authentication. However, it is better to choose one or the other, as appropriate. IEEE 802.1X is a standard framework for network access control that uses a central RADIUS server for user authentication. This control feature prevents unauthorized access to the network by requiring an 802.1X client application to submit user credentials for authentication. The 802.1X standard uses the Extensible Authentication Protocol (EAP) to pass user credentials (either digital certificates, user names and passwords, or other) from the client to the RADIUS server. Client authentication is then verified on the RADIUS server before the access point grants client access to the network. The 802.1X EAP packets are also used to pass dynamic unicast session keys and static broadcast keys to wireless clients. Session keys are unique to each client and are used to encrypt and correlate traffic passing between a specific client and the access point. You can also enable broadcast key rotation, so the access point provides a dynamic broadcast key and changes it at a specified interval. The access point can also operate in a 802.1X supplicant mode. This enables the access point itself to be authenticated with a RADIUS server using a configured MD5 user name and password. This prevents rogue access points from gaining access to the network. Take note of the following points before configuring MAC address or 802.1X authentication: „ Use MAC address authentication for a small network with a limited number of users. MAC addresses can be manually configured on the access point itself without the need to set up a RADIUS server, but managing a large number of MAC addresses across many access points is very cumbersome. A RADIUS server can be used to centrally manage a larger database of user MAC addresses. „ Use IEEE 802.1X authentication for networks with a larger number of users and where security is the most important issue. When using 802.1X authentication, a RADIUS server is required in the wired network to centrally manage the credentials of the wireless clients. It also provides a mechanism for enhanced network security using dynamic encryption key rotation or W-Fi Protected Access (WPA). NOTE: If you configure RADIUS MAC authentication together with 802.1X, RADIUS MAC address authentication is performed prior to 802.1X authentication. If RADIUS MAC authentication succeeds, then 802.1X authentication is performed. If RADIUS MAC authentication fails, 802.1X authentication is not performed. 4-10