Users Guide
• L2 egress access list
If a rule is simply appended, existing counters are not aected.
Table 7. L2 and L3 Filtering on Switched Packets
L2 ACL Behavior L3 ACL Behavior Decision on Targeted Trac
Deny Deny L3 ACL denies.
Deny Permit L3 ACL permits.
Permit Deny L3 ACL denies.
Permit Permit L3 ACL permits.
NOTE: If you congure an interface as a vlan-stack access port, only the L2 ACL lters the packets. The L3 ACL applied to such
a port does not aect trac. That is, existing rules for other features (such as trace-list, policy-based routing [PBR], and QoS)
are applied to the permitted trac.
For information about MAC ACLs, refer to Layer 2.
Assign an IP ACL to an Interface
To pass trac through a congured IP ACL, assign that ACL to a physical interface, a port channel interface, or a VLAN.
The IP ACL is applied to all trac entering a physical or port channel interface and the trac is either forwarded or dropped depending on
the criteria and actions specied in the ACL.
The same ACL may be applied to dierent interfaces and that changes its functionality. For example, you can take ACL “ABCD” and apply it
using the in keyword and it becomes an ingress access list. If you apply the same ACL using the out keyword, it becomes an egress
access list. If you apply the same ACL to the Loopback interface, it becomes a Loopback access list.
Applying an IP ACL
To apply an IP ACL (standard or extended) to a physical or port channel interface, use the following commands.
1 Enter the interface number.
CONFIGURATION mode
interface interface slot/port
2 Congure an IP address for the interface, placing it in Layer-3 mode.
INTERFACE mode
ip address ip-address
3 Apply an IP ACL to trac entering or exiting an interface.
INTERFACE mode
ip access-group access-list-name {in} [implicit-permit] [vlan vlan-range | vrf vrf-range]
[layer3]
NOTE
:
• The number of entries allowed per ACL is hardware-dependent. For detailed specication about entries allowed per ACL, refer
to your line card documentation.
• One of the usage scenarios is to avoid ACL being applied on the L2 trac which comes in via ICL. The layer 3 keyword can be
used at the VLAN level.
4 Apply rules to the new ACL.
INTERFACE mode
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Access Control Lists (ACLs)