Administrator Guide

Table Of Contents
Access Control Lists 647
Interface ACLs and PBR Interaction
PBR can be configured only on VLAN routing interfaces. However, user-
defined ACLs can be configured on all types of interfaces, including physical
interfaces, port-channels, and VLANs. When processing packets on which
both PBR and user-defined ACLs are configured, routing policy is performed
only after the application of all user-defined VLAN and interface ACLs.
Only packets that do not match any user-defined ingress deny ACLs rules
configured on an incoming interface are eligible for processing by PBR. User-
defined interface ACLs have a higher precedence than user-defined VLAN
ACLs or PBR ACLs. In the case of conflicting actions, the user-defined
interface ACL takes precedence. Specifically, if a user-defined interface ACL
drops a packet (deny), routing policy is not applied to the packet. Likewise, if
a user defined VLAN interface ACL drops a packet, routing policy is not
applied to the packet.
In many cases, the switch is capable of taking multiple actions on a packet,
irrespective of whether the action is configured on an ACL used in a route-
map or on an ACL configured on a port. For example, the system can both
rate limit packets on ingress with an interface ACL and set the ip precedence
on packets that do not exceed the rate limit with a PBR ACL.
The following table describes the action resolution mechanism when a packet
matches both the PBR rules configured on a VLAN routing interface and a
permit ACL rule configured on a physical interface (the deny ACL action is
included for emphasis):
PBR Action (VLAN) ACL Action (Interface) Result
set ip precedence deny deny
mirror both
redirect both (see Note 1)
rate limit both
set interface null0 deny deny (see Note 2)
mirror mirror
redirect redirect
rate limit deny
set ip next-hop (default) deny deny