Configuring Vlan Maps; Vlan Map Configuration Guidelines - Cisco Catalyst 3750-E Software Configuration Manual

Chapter 35 Configuring Network Security with ACLs

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.
For complete syntax and usage information 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
VLAN Map" section on page
Enter the vlan access-map global configuration command to create a VLAN ACL map entry.
Step 2
In access-map configuration mode, optionally enter an action—forward (the default) or drop—and
Step 3
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).
If the VLAN map is configured with a match clause for a type of packet (IP or MAC) and the map action
Note
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.
Use the vlan filter global configuration command to apply a VLAN map to one or more VLANs.
Step 4
These sections contain this configuration information:
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VLAN Map Configuration Guidelines

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OL-9775-08
"Creating Standard and Extended IPv4 ACLs" section on page 35-8
35-32.
VLAN Map Configuration Guidelines, page 35-31
Creating a VLAN Map, page 35-32
Applying a VLAN Map to a VLAN, page 35-35
Using VLAN Maps in Your Network, page 35-35
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.
If the VLAN map has at least one match clause for the type of packet (IP or MAC) and the packet
does not match any of these match clauses, the default is to drop the packet. If there is no match
clause for that type of packet in the VLAN map, the default is to forward the packet.
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
Configuring VLAN Maps
and the "Creating a
35-31