37-39
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 37 Configuring Network Security with ACLs Using VLAN Maps with Router ACLs
Examples of Router ACLs and VLAN Maps Applied to VLANs
This section gives examples of applying router ACLs and VLAN maps to a VLAN for switched, bridged,
routed, and multicast packets. Although the following illustrations show packets being forwarded to their
destination, each time the packet’s path crosses a line indicating a VLAN map or an ACL, it is also
possible that the packet might be dropped, rather than forwarded.
ACLs and Switched Packets, page 37-39
ACLs and Bridged Packets, page 37-39
ACLs and Routed Packets, page 37-40
ACLs and Multicast Packets, page 37-41

ACLs and Switched Packets

Figure 37-6 shows how an ACL is applied on packets that are switched within a VLAN. Packets switched
within the VLAN without being routed or forwarded by fallback bridging are only subject to the VLAN
map of the input VLAN.
Figure 37-6 Applying ACLs on Switched Packets

ACLs and Bridged Packets

Figure 37-7 shows how an ACL is applied on fallback-bridged packets. For bridged packets, only
Layer 2 ACLs are applied to the input VLAN. Only non-IP, non-ARP packets can be fallback-bridged.
VLAN 10
map
Frame
Input
router
ACL
Output
router
ACL
Routing function or
fallback bridge
VLAN 10 VLAN 20
Host C
(VLAN 10)
Host A
(VLAN 10)
VLAN 20
map
Packet
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