Chapter 23. Advanced IPv4 ACLs and Device Security

Cisco routers use IPv4 access control lists (ACL) for many different applications: to match packets to make filtering decisions, to match packets for Network Address Translation (NAT), to match packets to make quality of service (QoS) decisions, and for several other reasons.

Most IP ACLs are either standard or extended ACLs, with standard ACLs matching only the source IP address, and extended matching a variety of packet header fields. At the same time, IP ACLs are either numbered or named. Figure 23-1 shows the categories, and the main features of each, as introduced in the previous chapter.

Figure 23-1 Comparisons of IP ACL Types

This chapter discusses the other three categories of ACLs ...

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