Configuring MAC ACLs

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

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.

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 does not work on the Layer 3 control plane protocols such as HSRP, VRRP, OSPF, and so on. If you enable MAC packet classification on the VLANs, the basic functionalities will break on these protocols.

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 can apply an IP port ACL on the interface, but it will not filter traffic.

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 and it will filter traffic.

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

Guidelines and Limitations for MAC ACLs

MAC ACLs have the following configuration guidelines and limitations:

  • MAC ACLs apply to ingress traffic only.

  • Due to a hardware limitation, MAC ACL does not filter ARP packets on Cisco Nexus 3500 platform switches.

Configuring MAC ACLs

Creating a MAC ACL

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

Procedure

  Command or Action Purpose

Step 1

switch# configure terminal

Enters global configuration mode.

Step 2

switch(config)# mac access-list name

Creates the MAC ACL and enters ACL configuration mode.

Step 3

switch(config-mac-acl)# {permit | deny} source destination protocol

Creates a rule in the MAC ACL.

The permit and deny commands support many ways of identifying traffic.

Step 4

(Optional) 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

(Optional) switch(config-mac-acl)# show mac access-lists name

(Optional)

Displays the MAC ACL configuration.

Step 6

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

(Optional)

Copies the running configuration to the startup configuration.

Example

This example shows how to create a MAC ACL: 

switch# configure terminal
switch(config)# mac access-list acl-mac-01
switch(config-mac-acl)# permit 00c0.4f00.0000 0000.00ff.ffff any
switch(config-mac-acl)# statistics per-entry
switch(config-mac-acl)# show mac access-lists acl-mac-01

MAC ACL acl-mac-01
        statistics per-entry
        10 permit 00c0.4f00.0000 0000.00ff.ffff any

switch(config-mac-acl)# copy running-config startup-config

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.

Procedure

  Command or Action Purpose

Step 1

switch# configure terminal

Enters global configuration mode.

Step 2

switch(config)# mac access-list name

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

Step 3

(Optional) switch(config-mac-acl)# [sequence-number] {permit | deny} source destination protocol

(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.

Step 4

(Optional) switch(config-mac-acl)# no {sequence-number | {permit | deny} source destination protocol}

(Optional)

Removes the rule that you specify from the MAC ACL.

The permit and deny commands support many ways of identifying traffic.

Step 5

(Optional) switch(config-mac-acl)# [no] 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

(Optional) switch(config-mac-acl)# show mac access-lists name

(Optional)

Displays the MAC ACL configuration.

Step 7

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

(Optional)

Copies the running configuration to the startup configuration.

Example

This example shows how to change a MAC ACL: 

switch# configure terminal
switch(config)# mac access-list acl-mac-01
switch(config-mac-acl)# 100 permit 00c0.4f00.00 0000.00ff.ffff any
switch(config-mac-acl)# 80 permit 00c0.4f00.00 0000.00ff.ffff any
switch(config-mac-acl)# no 80
switch(config-mac-acl)# statistics per-entry
switch(config-mac-acl)# show mac access-lists acl-mac-01

MAC ACL acl-mac-01
        statistics per-entry
        10 permit 00c0.4f00.0000 0000.00ff.ffff any
        100 permit 00c0.4f00.0000 0000.00ff.ffff any

switch(config-mac-acl)# copy running-config startup-config

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.

Procedure

  Command or Action Purpose

Step 1

switch# configure terminal

Enters global configuration mode.

Step 2

switch(config)# resequence mac access-list name starting-sequence-number increment

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

(Optional) switch(config)# show mac access-lists name

(Optional)

Displays the MAC ACL configuration.

Step 4

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

(Optional)

Copies the running configuration to the startup configuration.

Example

This example shows how to change the sequence of a MAC ACL: 

switch# configure terminal
switch(config)# resequence mac access-list acl-mac-01 100 15
switch(config)# show mac access-lists acl-mac-01

MAC ACL acl-mac-01
        statistics per-entry
        100 permit 00c0.4f00.0000 0000.00ff.ffff any
        115 permit 00c0.4f00.0000 0000.00ff.ffff any

switch(config)# copy running-config startup-config

Removing a MAC ACL

You can remove a MAC ACL from the device.

Procedure

  Command or Action Purpose

Step 1

switch# configure terminal

Enters global configuration mode.

Step 2

switch(config)# no mac access-list name

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

Step 3

(Optional) switch(config)# show mac access-lists name summary

(Optional)

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

Step 4

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

(Optional)

Copies the running configuration to the startup configuration.

Example

This example shows how to remove a MAC ACL: 

switch# configure terminal
switch(config)# show mac access-lists

MAC ACL acl-mac-01
        statistics per-entry
        100 permit 00c0.4f00.0000 0000.00ff.ffff any
        115 permit 00c0.4f00.0000 0000.00ff.ffff any
MAC ACL acl-mac-02
        statistics per-entry
        10 permit 00a0.3f00.0000 0000.00dd.ffff any
MAC ACL acl-mac-03
        statistics per-entry
        10 permit 00b0.5f00.0000 0000.00aa.fbbf any

switch(config)# no mac access-list acl-mac-02
switch(config)# show mac access-lists acl-mac-02 summary
switch(config)# show mac access-lists

MAC ACL acl-mac-01
        statistics per-entry
        100 permit 00c0.4f00.0000 0000.00ff.ffff any
        115 permit 00c0.4f00.0000 0000.00ff.ffff any
MAC ACL acl-mac-03
        statistics per-entry
        10 permit 00b0.5f00.0000 0000.00aa.fbbf any

switch(config)# copy running-config startup-config

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.

Procedure

  Command or Action Purpose

Step 1

switch# configure terminal

Enters global configuration mode.

Step 2

Enter one of the following commands:

  • switch(config)# interface ethernet slot/port
  • switch(config)# interface port-channel channel-number

  • 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

switch(config-if)# mac port access-group access-list

Applies a MAC ACL to the interface.

Step 4

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

(Optional)

Displays ACL configuration.

Step 5

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

(Optional)

Copies the running configuration to the startup configuration.

Example

This example shows how to apply a MAC ACL as a port ACL to an Ethernet interface: 

switch# configure terminal
switch(config)# interface ethernet 1/3
switch(config-if)# mac port access-group acl-mac-01
switch(config-if)# show running-config aclmgr

!Command: show running-config aclmgr
!Time: Sat Jul 19 23:36:04 2014

version 6.0(2)A4(1)
mac access-list acl-mac-01
  statistics per-entry
  100 permit 00C0.4F00.0000 0000.00FF.FFFF any
  115 permit 00C0.4F00.0000 0000.00FF.FFFF any
mac access-list acl-mac-03
  statistics per-entry
  10 permit 00B0.5F00.0000 0000.00AA.FBBF any
ip access-list copp-system-acl-bfd
  10 permit udp any any eq 3784
ip access-list copp-system-acl-eigrp
  10 permit eigrp any any
ip access-list copp-system-acl-ftp
  10 permit tcp any any eq ftp-data
  20 permit tcp any any eq ftp
  30 permit tcp any eq ftp-data any
  40 permit tcp any eq ftp any

...

interface Ethernet1/3
  mac port access-group acl-mac-01

switch(config-if)# copy running-config startup-config

This example shows how to apply a MAC ACL as a port ACL to a port-channel interface: 

switch# configure terminal
switch(config)# interface port-channel 5
switch(config-if)# mac port access-group acl-mac-01
switch(config-if)# show running-config aclmgr

!Command: show running-config aclmgr
!Time: Sat Jul 19 23:37:04 2014

version 6.0(2)A4(1)
mac access-list acl-mac-01
  statistics per-entry
  100 permit 00C0.4F00.0000 0000.00FF.FFFF any
  115 permit 00C0.4F00.0000 0000.00FF.FFFF any
mac access-list acl-mac-03
  statistics per-entry
  10 permit 00B0.5F00.0000 0000.00AA.FBBF any
ip access-list copp-system-acl-bfd
  10 permit udp any any eq 3784
ip access-list copp-system-acl-eigrp
  10 permit eigrp any any
ip access-list copp-system-acl-ftp
  10 permit tcp any any eq ftp-data
  20 permit tcp any any eq ftp
  30 permit tcp any eq ftp-data any
  40 permit tcp any eq ftp any


...

interface port-channel5
  mac port access-group acl-mac-01

switch(config-if)# copy running-config startup-config

Enabling or Disabling MAC Packet Classification

You can enable or disable MAC packet classification on a per VLAN basis.

Procedure

  Command or Action Purpose

Step 1

config t

Example:

switch# config t
switch(config)#

Enters global configuration mode.

Step 2

vlan vlan-number

Example:

switch(config)# vlan 10
switch(config-vlan)#

Creates a VLAN interface. The number range is from 1 to 4094.

Step 3

[no] mac packet-classify

Example:

switch(config-vlan)# mac packet-classify
switch(config-vlan)#

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

Step 4

exit

Example:

switch(config-vlan)# exit
switch(config)#

Exits the vlan configuration.

Step 5

(Optional) show running-config vlan vlan-number

(Optional)

Displays the running configuration.

Example

This example shows how to enable MAC packet classification on a per VLAN basis: 

switch# configure terminal
switch(config)# vlan 50
switch(config-vlan)# mac packet-classify
switch(config-vlan)# exit
switch(config)# show running-config vlan 50

!Command: show running-config interface Vlan50
!Time: Wed Aug  6 20:39:03 2014

version 6.0(2)A4(1)

interface Vlan50
  mac packet-classify

switch(config-if)# copy running-config startup-config

Verifying the MAC ACL Configuration

To display MAC ACL configuration information, perform one of the following tasks.

Command

Purpose

show mac access-lists

Displays the MAC ACL configuration.

show running-config aclmgr [all]

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

Note

 

The all option displays both the default (CoPP-configured) and user-configured ACLs in the running configuration.

show startup-config aclmgr [all]

Displays the ACL startup configuration.

Note

 

The all option displays both the default (CoPP-configured) and user-configured ACLs in the startup configuration.

Clearing MAC ACL Statistics

You can clear MAC ACL statistics by using the clear mac access-list counters command

Command Purpose

clear mac access-list counters

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