CCNA Quick Reference Sheets (CCNA Exam 640-802)

Section 7. Managing Traffic with ACLs

As a network grows, it becomes more important to manage the increased traffic going across the network. Access lists help limit traffic by filtering based on packet characteristics. Access lists define a set of rules that routers use to identify particular types of traffic. Access lists can be used to filter both incoming and outgoing traffic on a router’s interface. An access list applied to a router specifies only rules for traffic going through the router. Traffic originating from a router is not affected by that router’s access lists. (It is subject to access lists within other routers as it passes through them.)

Access lists are used for many reasons. Cisco security devices like firewalls and VPN concentrators ...