Access Control Lists (ACLs) on Cisco Routers

Access Control Lists, or ACLs, are a tool that is used to define traffic on Cisco routers.

By themselves, they merely identify a particular set of traffic. How you apply the ACL then determines what occurs to that traffic.

For instance, if you apply an ACL to…

• … an interface? Matched traffic is allowed through

• … a Crypto map? Matched traffic is secured and sent through a VPN

• … a NAT configuration? Matched traffic is translated

• … a NAT Exemption configuration? Matched traffic is not translated

• … a Route Map? Matched routing advertisement are accepted

• … a QoS Classification? Matched traffic is prioritized (or de-prioritized)

The core of doing any of these successfully is understanding how to configure access lists on Cisco routers. And that is what this video series will teach you.

Of all the ways to apply an ACL listed above, the most common is to applying and ACL to an Interface. The purpose of such an ACL is to filter the “bad packets” from the “good packets”. In fact, when you apply an ACL to an interface, it is sometimes referred to as a Packet Filter.

To that end, Packet Filter ACLs are the focus of this video series. But, watching this video series will teach you how to configure ACLs for any other application listed above.