The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.
The MAC Authentication Bypass feature is a MAC-address-based authentication mechanism that allows clients in a network to integrate with the Cisco Identity Based Networking Services (IBNS) and Network Admission Control (NAC) strategy using the client MAC address. The MAC Authentication Bypass feature is applicable to the following network environments:
Standalone MAC Authentication Bypass (MAB) is an authentication method that grants network access to specific MAC addresses regardless of 802.1X capability or credentials. As a result, devices such as cash registers, fax machines, and printers can be readily authenticated, and network features that are based on authorization policies can be made available.
Before standalone MAB support was available, MAB could be configured only as a failover method for 802.1x authentication. Standalone MAB is independent of 802.1x authentication.
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see 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 at the end of this document.
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.
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. See the Cisco IOS Security Configuration Guide: Securing User Services , Release 15.0, for more information.
You should understand the concepts of the RADIUS protocol and have an understanding of how to create and apply access control lists (ACLs). For more information, see the documentation for your Cisco platform and the Cisco IOS Security Configuration Guide: Securing User Services , Release 15.0.
The switch must have a RADIUS configuration and be connected to the Cisco secure access control server (ACS). For more information, see the User Guide for Secure ACS Appliance 3.2 .
The capabilities of devices connecting to a given network can be different, thus requiring that the network support different authentication methods and authorization policies. The Cisco IOS Auth Manager handles network authentication requests and enforces authorization policies regardless of authentication method. The Auth Manager maintains operational data for all port-based network connection attempts, authentications, authorizations, and disconnections and, as such, serves as a session manager.
The possible states for Auth Manager sessions are as follows:
MAB uses the MAC address of the connecting device to grant or deny network access. To support MAB, the RADIUS authentication server maintains a database of MAC addresses for devices that require access to the network. MAB generates a RADIUS request with a MAC address in the Calling-Station-Id (attribute 31) and Service-Type (attribute 6) with a value of 10. After a successful authentication, the Auth Manager enables various authorization features specified by the authorization policy, such as ACL assignment and VLAN assignment.
Perform this task to enable the MAC Authentication Bypass feature on an 802.1X port.
Ports enabled with the Standalone MAB feature can use the MAC address of connecting devices to grant or deny network access. Perform the steps described in this section to enable standalone MAB on individual ports.
Before you can configure standalone MAB, the switch must be connected to a Cisco Secure ACS server and RADIUS authentication, authorization, and accounting (AAA) must be configured.
Command or Action | Purpose | |
---|---|---|
|
Example: Switch> enable |
Enables privileged EXEC mode.
|
|
Example: Switch# configure terminal |
Enters global configuration mode. |
|
Example: Switch(config)# interface FastEthernet2/1 |
Enters interface configuration mode. |
|
Example: Switch(config-if)# switchport |
Places interface in Layer2-switched mode. |
|
Example: Switch(config-if)# switchport mode access |
Sets a nontrunking, nontagged single VLAN Layer 2 interface. |
|
Example: Switch(config-if)# authentication port-control auto |
Configures the authorization state of the port. |
|
Example: Switch(config-if)# mab |
Enables MAB. |
|
Example: Switch(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
The following commands can help troubleshoot standalone MAB:
By default, ports are not automatically reauthenticated. You can enable automatic reauthentication and specify how often reauthentication attempts are made.
Command or Action | Purpose | |
---|---|---|
|
Example: Switch> enable |
Enables privileged EXEC mode.
|
|
Example: Switch# configure terminal |
Enters global configuration mode. |
|
Example: Switch(config)# interface FastEthernet2/1 |
Enters interface configuration mode. |
|
Example: Switch(config-if)# switchport |
Places interface in Layer2-switched mode. |
|
Example: Switch(config-if)# switchport mode access |
Sets a nontrunking, nontagged single VLAN Layer 2 interface. |
|
Example: Switch(config-if)# authentication port-control auto |
Configures the authorization state of the port. |
|
Example: Switch(config-if)# mab |
Enables MAB. |
|
Example: Switch(config-if)# authentication periodic |
Enables reauthentication. |
|
Example: Switch(config-if)# authentication timer reauthenticate 900 |
Configures the time, in seconds, between reauthentication attempts. |
|
Example: Switch(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
When there is a security violation on a port, the port can be shut down or traffic can be restricted. By default, the port is shut down. You can configure the period of time for which the port is shut down.
Command or Action | Purpose | |
---|---|---|
|
Example: Switch> enable |
Enables privileged EXEC mode.
|
|
Example: Switch# configure terminal |
Enters global configuration mode. |
|
Example: Switch(config)# interface FastEthernet2/1 |
Enters interface configuration mode. |
|
Example: Switch(config-if)# switchport |
Places interface in Layer2-switched mode. |
|
Example: Switch(config-if)# switchport mode access |
Sets a nontrunking, nontagged single VLAN Layer 2 interface. |
|
Example: Switch(config-if)# authentication port-control auto |
Configures the authorization state of the port. |
|
Example: Switch(config-if)# mab |
Enables MAB. |
|
Example: Switch(config-if)# authentication violation shutdown |
Configures the action to be taken when a security violation occurs on the port. |
|
Example: Switch(config-if)# authentication timer restart 30 |
Configures the period of time, in seconds, after which an attempt is made to authenticate an unauthorized port. |
|
Example: Switch(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
The following example shows how to configure standalone MAB on a port. In this example, the client is reauthenticated every 1200 seconds and the connection is dropped after 600 seconds of inactivity.
enable configure terminal interface GigabitEthernet2/1 switchport switchport mode access switchport access vlan 2 authentication port-control auto mab authentication violation shutdown authentication timer restart 30 authentication periodic authentication timer reauthenticate 1200 authentication timer inactivity 600
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
|
Authentication commands |
Cisco IOS Security Command Reference |
IEEE 802.1x--Flexible Authentication |
Cisco IOS Security Configuration Guide: Securing User Services |
Standard |
Title |
---|---|
None |
-- |
MIB |
MIBs Link |
---|---|
|
To locate and download MIBs for selected platforms, Cisco IOS software releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFC |
Title |
---|---|
RFC 3580 |
IEEE 802.1x Remote Authentication Dial In User Service (RADIUS) |
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. |
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 Configuring MAC Authentication Bypass |
Feature Name |
Releases |
Feature Information |
---|---|---|
MAC Authentication Bypass (MAB) |
12.1(22)T 12.2(31)SG 12.2(33)SXH15.1(4)M |
The MAC Authentication Bypass feature is a MAC-address-based authentication mechanism that allows clients in a network to integrate with the Cisco IBNS and NAC strategy using the client MAC address. In Cisco IOS Release 15.1(4)M support was extended for Integrated Services Router Generation 2 (ISR G2) platforms. The following commands were introduced or modified: dot1x mac-auth-bypass, show dot1x interface. |
Standalone MAB Support |
12.2(33)SXI |
This feature grants network access to devices based on MAC address regardless of 802.1x capability or credentials. The following commands were introduced or modified: authentication periodic, authentication port-control, authentication timer inactivity, authentication timer reauthenticate, authentication timer restart, authentication violation, debug authentication, mab, show authentication interface, show mab, show authentication registrations, show authentication sessions. |
Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.