Besides setting a maximum on the number of MAC addresses, we can also use port security to filter MAC addresses. You can use this to only allow specific MAC addresses. 03-09-2022 04:24 AM - edited 03-09-2022 04:25. An Access Control List (ACL) is a list of network traffic filters and correlated actions used to improve security. An ACL contains the hosts that are permitted or denied access to the network device. e it will start behaving like a hub).