IEEE 802.1X Multiple Authentication

The IEEE 802.1X Multiple Authentication feature provides a means of authenticating multiple hosts on a single port. With both 802.1X and non-802.1X devices, multiple hosts can be authenticated using different methods. Each host is individually authenticated before it can gain access to the network resources.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Prerequisites for IEEE 802.1X Multiple Authentication

IEEE 802.1X Port-Based Network Access Control

You should understand the concepts of port-based network access control and have an understanding of how to configure port-based network access control on your Cisco platform.

Before you can use the IEEE 802.1X Multiple Authentication feature, the switch must be connected to a Cisco secure Access Control Server and RADIUS authentication, authorization, and accounting (AAA) must be configured for web authentication. ACL download must be enabled.

If the authentication order includes the 802.1X port authentication method, you must enable IEEE 802.1X authentication on the switch.

If the authentication order includes web authentication, configure a fallback profile that enables web authentication on the switch and the interface.

You should understand the concepts of the RADIUS protocol and have an understanding of how to create and apply access control lists (ACLs).

The switch must have a RADIUS configuration and be connected to the Cisco secure access control server (ACS).

Restrictions for IEEE 802.1X Multiple Authentication

  • Only one voice VLAN is supported on a multiple authentication port.

  • You cannot configure a guest VLAN or an authentication failed VLAN in multiple authentication mode.

  • When a port is in multiple authentication mode, the guest VLAN and authentication failed VLAN features do not activate.

  • In multiple authentication mode, only multicast EAPOL packets are accepted by the port.

  • The web authentication method is not supported on Cisco integrated services routers (ISRs) or Integrated Services Routers Generation 2 (ISR-G2s) in Cisco IOS 15.2(2)T.

  • Inactivity aging is not supported on Cisco ISRs or ISR-G2s in multiple authentication mode.

  • This feature does not support standard ACLs on the switch port.

  • Configuring the same VLAN ID for both access and voice traffic (using the switchport access vlan vlan-id and the switchport voice vlan vlan-id commands) will fail if authentication has already been configured on the port.

  • Configuring authentication on a port on which you have already configured switchport access vlan vlan-id and switchport voice vlan vlan-id will fail if the access VLAN and voice VLAN have been configured with the same VLAN ID.

Information About IEEE 802.1X Multiple Authentication

Guidelines for Configuring IEEE 802.1X Multiple Authentication

Assign a RADIUS-server-supplied VLAN in multiple authentication mode, under these conditions:

  • The host is the first host authorized on the port, and the RADIUS server supplies VLAN information.

  • Subsequent hosts are authorized with a VLAN that matches the operational VLAN.

  • A host is authorized on the port with no VLAN assignment, and subsequent hosts either have no VLAN assignment, or their VLAN information matches the operational VLAN.

  • The first host authorized on the port has a group VLAN assignment, and subsequent hosts either have no VLAN assignment, or their group VLAN matches the group VLAN on the port. Subsequent hosts must use the same VLAN from the VLAN group as the first host. If a VLAN list is used, all hosts are subject to the conditions specified in the VLAN list.

  • Only one voice VLAN assignment is supported on a multi-auth port .

  • After a VLAN is assigned to a host on the port, subsequent hosts must have matching VLAN information or be denied access to the port.

  • You cannot configure a guest VLAN or an auth-fail VLAN in multi-auth mode.

  • The behavior of the critical-auth VLAN is not changed for multi-auth mode. When a host tries to authenticate and the server is not reachable, all authorized hosts are reinitialized in the configured VLAN.

How to Configure IEEE 802.1X Multiple Authentication

Configuring IEEE 802.1X Multiple Authentication

Beginning in privileged EXEC mode, follow these steps to allow one client on the voice VLAN and multiple authenticated clients on the data VLAN, where each host is individually authenticated.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    radius-server vsa send authentication

    4.    interface interface-id

    5.    access-session host-mode [multi-auth | multi-domain | multi-host | single-host] interface-id

    6.    end

    7.    show access-session interface interface-id

    8.    copy running-config startup-config


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example: 
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted .

     
    Step 2 configure terminal


    Example: 
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 radius-server vsa send authentication


    Example: 
    Device(config)# radius-server vsa send authentication
     

    Configures the Network Access Server (NAS) to recognize and use vendor-specific attributes.

     
    Step 4 interface interface-id


    Example: 
    Device(config)# interface fastethernet 2/1
     

    Specifies the port to which multiple hosts are indirectly attached, and enters interface configuration mode.

     
    Step 5 access-session host-mode [multi-auth | multi-domain | multi-host | single-host] interface-id


    Example: 
    Device(config-if)# access-session host-mode multi-auth
     

    Allows one client on the voice VLAN and multiple authenticated clients on the data VLAN.

    • Each host is individually authenticated.

     
    Step 6 end


    Example: 
    Device(config-if)# end
     

    Returns to privileged EXEC mode.

     
    Step 7 show access-session interface interface-id


    Example: 
    Device# show access-session interface g1/0/23
     

    Verifies the entries.

     
    Step 8 copy running-config startup-config


    Example: 
    Device# copy running-config startup-config
     

    Saves entries in the configuration file.

     

    Configuration Examples for IEEE 802.1X Multiple Authentication

    Example: Configuring IEEE 802.1X Multiple Authentication

    aaa new-model
!
!
aaa authentication login CON local
aaa authentication login VTY local
aaa authentication dot1x default group radius
aaa authorization network default group radius 
aaa authorization auth-proxy default group radius 
aaa accounting auth-proxy default start-stop group radius
aaa accounting dot1x default start-stop group radius
!
!
!
!
!
aaa session-id common
!
dot1x system-auth-control
!

interface Gigabitethernet1/1/1
 switchport access vlan 20
 switchport voice vlan 117
 no ip address
 authentication host-mode multi-auth
 authentication order mab
 authentication port-control auto
 mab
 dot1x pae authenticator
end

    Additional References

    Related Documents

    Related Topic

    Document Title

    Authentication commands

    Cisco IOS Security Command Reference Commands A to C

    IEEE 802.1x commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

    • Catalyst 4500 Series Switch Command Reference, Cisco IOS Release 12.2(25)SGA

    • Catalyst 3750 Switch Command Reference, Cisco IOS Release 12.2(25)SEE

    IPSec

    • IPsec Management Configuration Guide, Cisco IOS Release 15.2MT

    • Internet Key Exchange for IPsec VPNs Configuration Guide, Cisco IOS Release 15.2MT

    • Security for VPNs with IPsec Configuration Guide, Cisco IOS Release 15.2MT

    RADIUS

    RADIUS Configuration Guide, Cisco IOS Release 15.2MT

    Standalone MAB Support

    Standalone MAB Support

    Standards

    Standard

    Title

    IEEE 802.1X protocol

    —

    MIBs

    MIB

    MIBs Link

    CISCO–AUTH–FRAMEWORK–MIB

    CISCO–MAC–AUTH–BYPASS–MIB

    CISCO–PAE–MIB

    IEEE8021–PAE–MIB

    To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

    http:/​/​www.cisco.com/​go/​mibs

    RFCs

    RFC

    Title

    RFC-3580

    IEEE 802.1x Remote Authentication Dial In User Service (RADIUS)

    Technical Assistance

    Description

    Link

    The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

    http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

    Feature Information for IEEE 802.1X Multiple Authentication

    The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

    Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.
    Table 1 Feature Information for IEEE 802.1X Multiple Authentication

    Feature Name

    Releases

    Feature Information

    IEEE 8021.X Multiple Authentication

    Cisco IOS 15.2(2)T

    The IEEE 802.1X Multiple Authentication feature provides a means of authenticating multiple hosts on a single port. With both 802.1X and non-802.1X devices, multiple hosts can be authenticated using different methods. Each host is individually authenticated before it can gain access to the network resources.

    The following commands were introduced or modified: authentication host-mode.