Cisco Catalyst 3750 - Applying a MAC ACL to a Layer 2 Interface

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Catalyst 3750 Metro Switch Software Configuration Guide
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Chapter 25 Configuring Network Security with ACLs
Creating Named MAC Extended ACLs
Use the no mac access-list extended name global configuration command to delete the entire ACL. You
can also delete individual ACEs from named MAC extended ACLs.
This example shows how to create and display an access list named mac1, denying only EtherType
DECnet Phase IV traffic, but permitting all other types of traffic.
Switch(config)# mac access-list extended mac1
Switch(config-ext-macl)# deny any any decnet-iv
Switch(config-ext-macl)# permit any any
Switch(config-ext-macl)# end
Switch # show access-lists
Extended MAC access list mac1
deny any any decnet-iv
permit any any
Applying a MAC ACL to a Layer 2 Interface
After you create a MAC ACL, you can apply it to a Layer 2 interface to filter non-IPv4 traffic coming
in that interface. When you apply the MAC ACL, consider these guidelines:
• If you apply an ACL to a Layer 2 interface that is a member of a VLAN, the Layer 2 (port) ACL
takes precedence over an input Layer 3 ACL applied to the VLAN interface or a VLAN map applied
to the VLAN. Incoming packets received on the Layer 2 port are always filtered by the port ACL.
• You can apply no more than one IP access list and one MAC access list to the same Layer 2 interface.
The IP access list filters only IPv4 packets, and the MAC access list filters non-IPv4 packets.
• A Layer 2 interface can have only one MAC access list. If you apply a MAC access list to a Layer
2 interface that has a MAC ACL configured, the new ACL replaces the previously configured one.
Beginning in privileged EXEC mode, follow these steps to apply a MAC access list to control access to
a Layer 2 interface:
Step 5
show access-lists [number | name] Show the access list configuration.
Step 6
copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Identify a specific interface, and enter interface configuration
mode. The interface must be a physical Layer 2 interface (port
ACL).
Step 3
mac access-group {name} {in} Control access to the specified interface by using the MAC access
list.
Note Port ACLs are supported only in the inbound direction.
Step 4
end Return to privileged EXEC mode.
Step 5
show mac access-group [interface interface-id]
Display the MAC access list applied to the interface or all Layer 2
interfaces.
Step 6
copy running-config startup-config (Optional) Save your entries in the configuration file.