Which feature allows firewall ACLs to be configure automatically when new endpoint are attached to an EPG?

ARP network gleaning is a method for learning IP-to-MAC address mappings, which is a component of endpoint learning, but not the overarching feature responsible for dynamic ACL configuration.

Network stitching typically refers to connecting different network segments or orchestrating service chains, but it is not the primary mechanism for automatically configuring ACLs based on endpoint attachment.

Dynamic endpoint attach (or endpoint learning) is a core Cisco ACI feature where the fabric automatically detects new endpoints and their associated EPGs. Upon attachment, ACI dynamically pushes and applies the relevant network and security policies, including firewall ACLs derived from contracts, ensuring immediate policy enforcement without manual intervention.

Hardware proxy is a fabric optimization that allows ACI leaf switches to respond to ARP requests for known endpoints, reducing flood traffic, but it does not directly configure firewall ACLs.