Access control lists (ACLs) perform packet filtering to control which packets move through a network and
to where. The packet filtering provides security by helping to limit the network traffic, restrict the access of
users and devices to a network, and prevent the traffic from leaving a network. IP access lists reduce the
chanceofspoofinganddenial-of-service attacks andallow dynamic, temporaryuser-accessthrougha firewall.
IPaccesslists can also be used for purposes other than security,such as bandwidth control, restrict the content
of routing updates, redistribute routes, trigger dial-on-demand (DDR) calls, limit debug output, and identify
or classify traffic for quality of service (QoS) features. This module provides an overview of IP access lists.