This window appears when you select an interface or terminal line and click Modify on the Attach tab of the ACL window.
If you selected an interface on a Catalyst 2950 switch or Layer 3 interface (a routed port or an SVI) on a Catalyst 3550 switch, you can attach an ACL to filter inbound packets. For Catalyst 3550 switches, you can attach an ACL to filter outbound packets as well. See Steps for 2950 Interfaces and 3550 Layer 3 Interfaces.
If you selected a Layer 2 interface (a switch port) on a Catalyst 3550 switch, see Steps for 3550 Layer 2 Interfaces.
When you finish the steps, click OK.
Note: You are not required to select both an inbound and an outbound ACL for Catalyst 3550 switches. If you do, it can be the same ACL or different ACLs.
An IP ACL filters only IP packets; a MAC ACL filters only MAC packets. Attach both ACL types if you want to filter both types of packets.