Information About Vlan Access Control Lists - Cisco Catalyst 2960 series Configuration Manual
Consolidated platform configuration guide, ios release 15.2(4)e
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Also See for Catalyst 2960 series:
- Software configuration manual (980 pages) ,
- Command reference manual (800 pages) ,
- Configuration manual (120 pages)
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Information About VLAN Access Control Lists
Information About VLAN Access Control Lists
VLAN Maps
Use VLAN ACLs or VLAN maps to access-control all traffic. You can apply VLAN maps to all packets that
are routed into or out of a VLAN or are bridged within a VLAN in the switch or switch stack.
Use VLAN maps for security packet filtering. VLAN maps are not defined by direction (input or output).
You can configure VLAN maps to match Layer 3 addresses for IPv4 traffic.
All non-IP protocols are access-controlled through MAC addresses and Ethertype using MAC VLAN maps.
(IP traffic is not access controlled by MAC VLAN maps.) You can enforce VLAN maps only on packets
going through the switch; you cannot enforce VLAN maps on traffic between hosts on a hub or on another
switch connected to this switch.
With VLAN maps, forwarding of packets is permitted or denied, based on the action specified in the map.
This shows how a VLAN map is applied to prevent a specific type of traffic from Host A in VLAN 10 from
being forwarded. You can apply only one VLAN map to a VLAN.
Figure 79: Using VLAN Maps to Control Traffic
VLAN Map Configuration Guidelines
VLAN maps are 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.
The following are the VLAN map configuration guidelines:
• If there is no ACL configured to deny traffic on an interface and no VLAN map is configured, all traffic
• Each VLAN map consists of a series of entries. The order of entries in an VLAN map is important. A
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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is permitted.
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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