This chapter covers the following exam topics:
4.1. Describe and configure basic routing concepts
4.1a. Packet forwarding
Most every other topic in the scope of CCNA-DC focuses on achieving a core goal of any TCP/IP network: delivering IPv4 packets from the source host to the destination host. This chapter focuses instead on preventing a subset of those packets from being allowed to reach their destinations, by using IPv4 access control lists (ACLs).
IPv4 ACLs have many uses, but the CCNA-DC exam focuses on their most commonly known use: as packet filters. You want hosts in one subnet to be able to communicate throughout your corporate network, but perhaps there is a pocket of servers ...