Setup Guide

ip access-list [standard | extended] name
To view which IP ACL is applied to an interface, use the show config command in INTERFACE mode, or use the show running-
config command in EXEC mode.
Example of Viewing ACLs Applied to an Interface
To lter trac on Telnet sessions, use only standard ACLs in the access-class command.
Counting ACL Hits
You can view the number of packets matching the ACL by using the count option when creating ACL entries.
1 Create an ACL that uses rules with the count option. Refer to Congure a Standard IP ACL Filter.
2 Apply the ACL as an inbound or outbound ACL on an interface.
3 show ip accounting access-list
EXEC Privilege mode
View the number of packets matching the ACL.
Congure Ingress ACLs
Ingress ACLs are applied to interfaces and to trac entering the system.
These system-wide ACLs eliminate the need to apply ACLs onto each interface and achieves the same results. By localizing target trac, it
is a simpler implementation.
To create an ingress ACL, use the ip access-group command in EXEC Privilege mode. The example shows applying the ACL, rules to
the newly created access group, and viewing the access list.
Example of Applying ACL Rules to Ingress Trac and Viewing ACL Conguration
To specify ingress, use the in keyword. Begin applying rules to the ACL with the ip access-list extended abcd command. To
view the access-list, use the show command.
Congure Egress ACLs
Egress ACLs are applied to line cards and aect the trac leaving the system. Conguring egress ACLs onto physical interfaces protects
the system infrastructure from attack — malicious and incidental — by explicitly allowing only authorized trac. These system-wide ACLs
eliminate the need to apply ACLs onto each interface and achieves the same results. By localizing target trac, it is a simpler
implementation.
To restrict egress trac, use an egress ACL. For example, when a denial of service (DOS) attack trac is isolated to a specic interface,
you can apply an egress ACL to block the ow from the exiting the box, thus protecting downstream devices.
To create an egress ACL, use the ip access-group command in EXEC Privilege mode. The example shows viewing the conguration,
applying rules to the newly created access group, and viewing the access list.
NOTE
: VRF based ACL congurations are not supported on the egress trac.
Example of Applying ACL Rules to Egress Trac and Viewing ACL Conguration
To specify ingress, use the out keyword. Begin applying rules to the ACL with the ip access-list extended abcd command. To
view the access-list, use the
show command.
Access Control Lists (ACLs)
107