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Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter33 Configuring Network Security with ACLs
Using PACL with VLAN Maps and Router ACLs
If the interface access group mode is prefer port, then on ly the input PACL is applied on the ingress
traffic from Host A. If the mode is prefer vlan, then only the VACL is applied to the ingress traffic from
Host A. If the mode is merge, the input PACL is first applied to the ingress traffic from Host A, and the
VACL is applied on the traffic.
Scenario 3: Host A is connected to an interface in VLAN 10, which has a VACL and an SVI configured.
The SVI has an input Router ACL configured and the interface has an input PACL configured, as shown
in Figure33-9:
Figure33-9 Scenario 3: VACL and Input Router ACL
If the interface access group mode is prefer port, then on ly the input PACL is applied on the ingress
traffic from Host A. If the mode is prefer vlan, then the merged results of the VACL and the input Router
ACL are applied to the ingress traffic from Host A. If the mode is merge, the input PACL is first applied
to the ingress traffic from Host A, the VACL is applied on the traffic and finally, and the input Router
ACL is applied to the traffic that needs routing. (that is, the merged results of the input PACL, VACL,
and input Router ACL are applied to the traffic).
Frame
Routing function
VLAN 10
Host A
(VLAN 10)
Packet
94094
Catalyst 4500 series switch
VLAN 20
Host B
(VLAN 20)
VLAN 10
map
Input
PACL
Input
router
ACL
Output
router
ACL
VLAN 20
map