Specifications

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Catalyst 2970 Switch Software Configuration Guide
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Chapter 26 Configuring Network Security with ACLs
Configuring VLAN Maps
Note The mac access-group interface configuration command is only valid when applied to a physical Layer
2 interface.You cannot use the command on EtherChannel port channels.
After receiving a packet, the switch checks it against the inbound ACL. If the ACL permits it, the switch
continues to process the packet. If the ACL rejects the packet, the switch discards it. When you apply an
undefined ACL to an interface, the switch acts as if the ACL has not been applied and permits all packets.
Remember this behavior if you use undefined ACLs for network security.
Configuring VLAN Maps
This section describes how to configure VLAN maps, which is the only way to control filtering within
a VLAN. VLAN maps have no direction. To filter traffic in a specific direction by using a VLAN map,
you need to include an ACL with specific source or destination addresses. If there is a match clause for
that type of packet (IP or MAC) in the VLAN map, the default action is to drop the packet if the packet
does not match any of the entries within the map. If there is no match clause for that type of packet, the
default is to forward the packet.
Note For complete syntax and usage information for the commands used in this section, refer to the command
reference for this release.
To create a VLAN map and apply it to one or more VLANs, perform these steps:
Step 1 Create the standard or extended IP ACLs or named MAC extended ACLs that you want to apply to the
VLAN. See the “Creating Standard and Extended IP ACLs” section on page 26-6 and the “Creating a
VLAN Map” section on page 26-23.
Step 2 Enter the vlan access-map global configuration command to create a VLAN ACL map entry.
Step 3 In access map configuration mode, optionally enter an action—forward (the default) or drop—and
enter the match command to specify an IP packet or a non-IP packet (with only a known MAC address)
and to match the packet against one or more ACLs (standard or extended).
Note If the VLAN map has a match clause for the type of packet (IP or MAC) and the packet does not
match the type, the default is to drop the packet. If there is no match clause in the VLAN map
for that type of packet, and no action specified, the packet is forwarded.
Step 4 Use the vlan filter global configuration command to apply a VLAN map to one or more VLANs.
This section contains these topics:
• VLAN Map Configuration Guidelines, page 26-23
• Creating a VLAN Map, page 26-23
• Applying a VLAN Map to a VLAN, page 26-26
• Using VLAN Maps in Your Network, page 26-26