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37-31

Catalyst 3750-X and 3560-X Switch Software Configuration Guide

OL-21521-01

Chapter 37 Configuring Network Security with ACLs

Configuring VLAN Maps

Note VLAN maps are not supported on switches running the LAN base feature set.

This section describes how to configure VLAN maps, which is the only way to control filtering within

a VLA

N. 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.

For complete syntax and usage inf

ormation for the commands used in this section, see 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 IPv4 ACLs or named MAC extended ACLs that you want to apply to the

VLAN. See the “Creating Standard and Extended IPv4 ACLs” section on page 37-8 and the “Creating a

VLAN Map” section on page 37-32.

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 is configured with a match clause for a type of packet (IP or MAC) and the map action

is drop, all packets that match the type are dropped. If the VLAN map has no match clause, and the

configured action is drop, all IP and Layer 2 packets are dropped.

Step 4 Use the vlan filter global configuration command to apply a VLAN map to one or more VLANs.

These sections contain this configuration information:

• VLAN Map Configuration Guidelines, page 37-31

• Creating a VLAN Map, page 37-32

• Applying a VLAN Map to a VLAN, page 37-35

• Using VLAN Maps in Your Network, page 37-35

VLAN Map Configuration Guidelines

• If there is no ACL configured to deny traffic on an interface and no VLAN map is configured, all

traffic is permitted.

• Each VLAN map consists of a series of entries. The order of entries in an VLAN map is important.

A packet that comes into the switch is tested against the first entry in the VLAN map. If it matches,

the action specified for that part of the VLAN map is taken. If there is no match, the packet is tested

against the next entry in the map.

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