Firewall Configuration: Input Interface, Output Interface, and FragmentsIf an interface (such as eth0 or eth1) is entered in the “Input Interface” field, incoming packets are filtered for the specified interface. If an interface is entered in the “Output Interface” field, outgoing packets are filtered for the specified interface. The input and output interface fields are shown in the following figure along with the options on the “Fragments” pull-down menu.Firewall Configuration “Add Rule” and “Edit Rule” Input and Output Interface Fields and Fragments Menu Options
The input interface (ethN) for the packet The output interface (ethN) for the packet