Required Network Components; Best-Practice Requirements And Recommendations - Cisco 7975G Software Manual

802.1X Authentication

Required Network Components

Support for 802.1X authentication on Cisco Unified IP Phones requires several components, including:
• Cisco Unified IP Phone: The phone acts as the 802.1X supplicant, which initiates the request to access
the network.
• Cisco Secure Access Control Server (ACS) (or other third-party authentication server): The authentication
server and the phone must both be configured with a shared secret that authenticates the phone.
• Cisco Catalyst Switch (or other third-party switch): The switch must support 802.1X, so it can act as
the authenticator and pass the messages between the phone and the authentication server. After the
exchange completes, the switch grants or denies the phone access to the network.

Best-Practice Requirements and Recommendations

• Enable 802.1X Authentication: If you want to use the 802.1X standard to authenticate Cisco Unified IP
Phones, make sure that you have properly configured the other components before you enable the
standard on the phone.
• Configure PC Port: The 802.1X standard does not take into account the use of VLANs and thus
recommends that only a single device be authenticated to a specific switch port. However, some switches
(such as Cisco Catalyst switches) support multidomain authentication. The switch configuration determines
whether you can connect a PC to the phone PC port.
• Configure Voice VLAN: Because the 802.1X standard does not account for VLANs, you should configure
this setting according to the switch support.
• Enter MD5 Shared Secret: If you disable 802.1X authentication or perform a factory reset on the phone,
the previously configured MD5 shared secret is deleted.
Related Topics
Security Configuration Menu, on page 101
Cisco Unified IP Phone 7975G, 7971G-GE, 7970G, 7965G, and 7945G Administration Guide for Cisco Unified
Communications Manager 9.0 (SCCP and SIP)
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◦ Enabled: If you use a switch that supports multidomain authentication, you can enable the PC port
and connect a PC to it. In this case, Cisco Unified IP Phones support proxy EAPOL-Logoff to
monitor the authentication exchanges between the switch and the attached PC. For more information
about IEEE 802.1X support on the Cisco Catalyst switches, see the Cisco Catalyst switch
configuration guides at:
http://www.cisco.com/en/US/products/hw/switches/ps708/tsd_products_support_series_home.html
◦ Disabled: If the switch does not support multiple 802.1X-compliant devices on the same port, you
should disable the PC Port when 802.1X authentication is enabled. If you do not disable this port
and subsequently attempt to attach a PC to it, the switch will deny network access to the phone
and the PC.
◦ Enabled: If you use a switch that supports multidomain authentication, you can continue to use
the voice VLAN.
◦ Disabled: If the switch does not support multidomain authentication, disable the Voice VLAN and
consider assigning the port to the native VLAN.
Cisco Unified IP Phone