In this section, you learned how to control traffic flow and secure your network.
ACL concepts: Standard ACLs filter by source IP only. Extended ACLs filter by source, destination, protocol, and port. ACLs process top-down with first-match logic. An implicit deny exists at the end of every ACL. Place extended ACLs close to the source, standard ACLs close to the destination.
Firewall concepts: Stateless firewalls check each packet independently. Stateful firewalls track connections. Zones segment networks into trust levels. NGFWs add application awareness and intrusion prevention. IDS monitors and alerts. IPS blocks attacks inline.