Cisco Nexus 7000 Series NX-OS Security Configuration Guide, Release 4.2
Configuring MAC ACLs
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Configuring MAC ACLs

This chapter describes how to configure MAC access lists (ACLs) on Cisco NX-OS devices.

This chapter contains the following sections:

Information About MAC ACLs

MAC ACLs are ACLs that use information in the Layer 2 header of packets to filter traffic. MAC ACLs share many fundamental concepts with IP ACLs, including support for virtualization.

Related Concepts

MAC Packet Classification

MAC packet classification allows you to control whether a MAC ACL that is on a Layer 2 interface applies to all traffic entering the interface, including IP traffic, or to non-IP traffic only.

MAC Packet Classification State Effect on Interface

Enabled


  • A MAC ACL that is on the interface applies to all traffic entering the interface, including IP traffic.

  • You cannot apply an IP port ACL on the interface.

Disabled


  • A MAC ACL that is on the interface applies only to non-IP traffic entering the interface.

  • You can apply an IP port ACL on the interface

Related Tasks

Licensing Requirements for MAC ACLs

This table shows the licensing requirements for this feature.

Product

License Requirement

Cisco NX-OS

MAC ACLs require no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For an explanation of the Cisco NX-OS licensing scheme, see the Cisco Nexus 7000 Series NX-OS Licensing Guide, Release 4.2.

Prerequisites for MAC ACLs

There are no prerequisites for configuring MAC ACLs.

Guidelines and Limitations for MAC ACLs

MAC ACLs have the following configuration guidelines and limitations:


  • MAC ACLs apply to ingress traffic only.

  • ACL statistics are not supported if the DHCP snooping feature is enabled.

Default Settings for MAC ACLs

This table lists the default settings for MAC ACL parameters.


Table 1 Default MAC ACLs Parameters

Parameters

Default

MAC ACLs

No MAC ACLs exist by default

ACL rules

Implicit rules apply to all ACLs

Configuring MAC ACLs

Creating a MAC ACL

You can create a MAC ACL and add rules to it.

SUMMARY STEPS

1.    configure terminal

2.    mac access-list name

3.    {permit | deny} source destination protocol

4.    (Optional) statistics per-entry

5.    (Optional) show mac access-lists name

6.    (Optional) copy running-config startup-config


DETAILED STEPS
 Command or ActionPurpose
Step 1 configure terminal


Example: 
switch# configure terminal
switch(config)#
 

Enters global configuration mode.

 
Step 2 mac access-list name


Example: 
switch(config)# mac access-list acl-mac-01
switch(config-mac-acl)#
 

Creates the MAC ACL and enters ACL configuration mode.

 
Step 3 {permit | deny} source destination protocol


Example: 
switch(config-mac-acl)# permit 00c0.4f00.0000 0000.00ff.ffff any
 

Creates a rule in the MAC ACL.

The permit and deny commands support many ways of identifying traffic. For more information, see the Cisco Nexus 7000 Series NX-OS Security Command Reference, Release 4.2.

 
Step 4 statistics per-entry


Example: 
switch(config-mac-acl)# statistics per-entry
  		(Optional)

Specifies that the device maintains global statistics for packets that match the rules in the ACL.

 
Step 5 show mac access-lists name


Example: 
switch(config-mac-acl)# show mac access-lists acl-mac-01
  		(Optional)

Displays the MAC ACL configuration.

 
Step 6 copy running-config startup-config


Example: 
switch(config-mac-acl)# copy running-config startup-config
  		(Optional)

Copies the running configuration to the startup configuration.

 

Changing a MAC ACL

You can remove a MAC ACL from the device.

Before You Begin

Use the show mac access-lists command with the summary keyword to find the interfaces that a MAC ACL is configured on.


SUMMARY STEPS

1.    configure terminal

2.    mac access-list name

3.    (Optional) [sequence-number] {permit | deny} source destination protocol

4.    (Optional) no {sequence-number | {permit | deny} source destination protocol}

5.    (Optional) [no] statistics per-entry

6.    (Optional) show mac access-lists name

7.    (Optional) copy running-config startup-config


DETAILED STEPS
 Command or ActionPurpose
Step 1 configure terminal


Example: 
switch# configure terminal
switch(config)#
 

Enters global configuration mode.

 
Step 2 mac access-list name


Example: 
switch(config)# mac access-list acl-mac-01
switch(config-mac-acl)#
 

Enters ACL configuration mode for the ACL that you specify by name.

 
Step 3 [sequence-number] {permit | deny} source destination protocol


Example: 
switch(config-mac-acl)# 100 permit mac 00c0.4f00.00 0000.00ff.ffff any
  		(Optional)

Creates a rule in the MAC ACL. Using a sequence number allows you to specify a position for the rule in the ACL. Without a sequence number, the rule is added to the end of the rules.

The permit and deny commands support many ways of identifying traffic. For more information, see the Cisco Nexus 7000 Series NX-OS Security Command Reference, Release 4.2.

 
Step 4 no {sequence-number | {permit | deny} source destination protocol}


Example: 
switch(config-mac-acl)# no 80
  		(Optional)

Removes the rule that you specify from the MAC ACL.

The permit and deny commands support many ways of identifying traffic. For more information, see the Cisco Nexus 7000 Series NX-OS Security Command Reference, Release 4.2.

 
Step 5 [no] statistics per-entry


Example: 
switch(config-mac-acl)# statistics per-entry
  		(Optional)

Specifies that the device maintains global statistics for packets that match the rules in the ACL.

The no option stops the device from maintaining global statistics for the ACL.

 
Step 6 show mac access-lists name


Example: 
switch(config-mac-acl)# show mac access-lists acl-mac-01
  		(Optional)

Displays the MAC ACL configuration.

 
Step 7 copy running-config startup-config


Example: 
switch(config-mac-acl)# copy running-config startup-config
  		(Optional)

Copies the running configuration to the startup configuration.

 

Changing Sequence Numbers in a MAC ACL

You can change all the sequence numbers assigned to rules in a MAC ACL. Resequencing is useful when you need to insert rules into an ACL and there are not enough available sequence numbers.

SUMMARY STEPS

1.    configure terminal

2.    resequence mac access-list name starting-sequence-number increment

3.    (Optional) show mac access-lists name

4.    (Optional) copy running-config startup-config


DETAILED STEPS
 Command or ActionPurpose
Step 1 configure terminal


Example: 
switch# configure terminal
switch(config)#
 

Enters global configuration mode.

 
Step 2 resequence mac access-list name starting-sequence-number increment


Example: 
switch(config)# resequence mac access-list acl-mac-01 100 10
 

Assigns sequence numbers to the rules contained in the ACL, where the first rule receives the number specified by the starting-sequence number that you specify. Each subsequent rule receives a number larger than the preceding rule. The difference in numbers is determined by the increment number that you specify.

 
Step 3 show mac access-lists name


Example: 
switch(config)# show mac access-lists acl-mac-01
  		(Optional)

Displays the MAC ACL configuration.

 
Step 4 copy running-config startup-config


Example: 
switch(config)# copy running-config startup-config
  		(Optional)

Copies the running configuration to the startup configuration.

 

Removing a MAC ACL

You can remove a MAC ACL from the device.

SUMMARY STEPS

1.    configure terminal

2.    no mac access-list name

3.    (Optional) show mac access-lists name summary

4.    (Optional) copy running-config startup-config


DETAILED STEPS
 Command or ActionPurpose
Step 1 configure terminal


Example: 
switch# configure terminal
switch(config)#
 

Enters global configuration mode.

 
Step 2 no mac access-list name


Example: 
switch(config)# no mac access-list acl-mac-01
switch(config)#
 

Removes the MAC ACL that you specify by name from the running configuration.

 
Step 3 show mac access-lists name summary


Example: 
switch(config)# show mac access-lists acl-mac-01 summary
  		(Optional)

Displays the MAC ACL configuration. If the ACL remains applied to an interface, the command lists the interfaces.

 
Step 4 copy running-config startup-config


Example: 
switch(config)# copy running-config startup-config
  		(Optional)

Copies the running configuration to the startup configuration.

 

Applying a MAC ACL as a Port ACL

You can apply a MAC ACL as a port ACL to any of the following interface types:


  • Layer 2 or Layer 3 Ethernet interfaces

  • Layer 2 or Layer 3 port-channel interfaces

Before You Begin

Ensure that the ACL that you want to apply exists and is configured to filter traffic in the manner that you need for this application.


SUMMARY STEPS

1.    configure terminal

2.    Enter one of the following commands:

  • interface ethernet slot/port
  • interface port-channel channel-number

3.    mac port access-group access-list

4.    (Optional) show running-config aclmgr

5.    (Optional) copy running-config startup-config


DETAILED STEPS
 Command or ActionPurpose
Step 1 configure terminal


Example: 
switch# configure terminal
switch(config)#
 

Enters global configuration mode.

 
Step 2Enter one of the following commands:
  • interface ethernet slot/port
  • interface port-channel channel-number


Example: 
switch(config)# interface ethernet 2/1
switch(config-if)#


Example: 
switch(config)# interface port-channel 5
switch(config-if)#
 

  • Enters interface configuration mode for a Layer 2 or Layer 3 interface.

  • Enters interface configuration mode for a Layer 2 or Layer 3 port-channel interface.

 
Step 3 mac port access-group access-list


Example: 
switch(config-if)# mac port access-group acl-01
 

Applies a MAC ACL to the interface.

 
Step 4 show running-config aclmgr


Example: 
switch(config-if)# show running-config aclmgr
  		(Optional)

Displays ACL configuration.

 
Step 5 copy running-config startup-config


Example: 
switch(config-if)# copy running-config startup-config
  		(Optional)

Copies the running configuration to the startup configuration.

 

Applying a MAC ACL as a VACL

You can apply a MAC ACL as a VACL.

Related Concepts

Enabling or Disabling MAC Packet Classification

You can enable or disable MAC packet classification on a Layer 2 interface.

Before You Begin

The interface must be configured as a Layer 2 interface.


Note

If the interface is configured with the ip port access-group command or the ipv6 port traffic-filter command, you cannot enable MAC packet classification until you remove the ip port access-group and ipv6 port traffic-filter commands from the interface configuration.


SUMMARY STEPS

1.    configure terminal

2.    Enter one of the following commands:

  • interface ethernet slot/port
  • interface port-channel channel-number

3.    [no] mac packet-classify

4.    (Optional) Enter one of the following commands:

  • show running-config interface ethernet slot/port
  • show running-config interface port-channel channel-number

5.    (Optional) copy running-config startup-config


DETAILED STEPS
 Command or ActionPurpose
Step 1 configure terminal


Example: 
switch# configure terminal
switch(config)#
 

Enters global configuration mode.

 
Step 2Enter one of the following commands:
  • interface ethernet slot/port
  • interface port-channel channel-number


Example: 
switch(config)# interface ethernet 2/1
switch(config-if)#


Example: 
switch(config)# interface port-channel 5
switch(config-if)#
 

  • Enters interface configuration mode for a Ethernet interface.

  • Enters interface configuration mode for a port-channel interface.

 
Step 3 [no] mac packet-classify


Example: 
switch(config-if)# mac packet-classify
 

Enables MAC packet classification on the interface. The no option disables MAC packet classification on the interface.

 
Step 4Enter one of the following commands:
  • show running-config interface ethernet slot/port
  • show running-config interface port-channel channel-number


Example: 
switch(config-if)# show running-config interface ethernet 2/1


Example: 
switch(config-if)# show running-config interface port-channel 5
  		(Optional)

  • Displays the running configuration of the Ethernet interface.

  • Displays the running configuration of the port-channel interface.

 
Step 5 copy running-config startup-config


Example: 
switch(config-if)# copy running-config startup-config
  		(Optional)

Copies the running configuration to the startup configuration.

 
Related Concepts

Verifying the MAC ACL Configuration

To display MAC ACL configuration information, perform one of the following tasks. For detailed information about the fields in the output from these commands, see the Cisco Nexus 7000 Series NX-OS Security Command Reference, Release 4.2.

Command

Purpose

show mac access-lists

Displays the MAC ACL configuration.

show running-config aclmgr

Displays the ACL configuration, including MAC ACLs and the interfaces that ACLs are applied to.

show running-config interface

Displays the configuration of the interface to which you applied the ACL.

Monitoring and Clearing MAC ACL Statistics

Use the show mac access-lists command to monitor statistics about a MAC ACL, including the number of packets that have matched each rule.

To monitor or clear MAC ACL statistics, use one of the commands in this table. For detailed information about these commands, see the Cisco Nexus 7000 Series NX-OS Security Command Reference, Release 4.2.

Command

Purpose

show mac access-lists

Displays the MAC ACL configuration. If the MAC ACL includes the statistics per-entry command, the show mac access-lists command output includes the number of packets that have matched each rule.

clear mac access-list counters

Clears statistics for all MAC ACLs or for a specific MAC ACL.

Configuration Example for MAC ACLs

The following example shows how to create a MAC ACL named acl-mac-01 and apply it to Ethernet interface 2/1, which is a Layer 2 interface in this example:

mac access-list acl-mac-01
  permit 00c0.4f00.0000 0000.00ff.ffff any 
interface ethernet 2/1
  mac port access-group acl-mac-01

Additional References for MAC ACLs

Related Documents

Related Topic

Document Title

MAC ACL commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

Cisco Nexus 7000 Series NX-OS Security Command Reference, Release 4.2

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

—

Feature History for MAC ACLs

This table lists the release history for this feature.
Table 2 Feature History for MAC ACLs

Feature Name

Releases

Feature Information

MAC ACLs

4.2(1)

Support was added for MAC packet classification.