When processing inbound Ethernet frames, which firewall filter is evaluated first by an EX Series switch?

When processing inbound Ethernet frames, the first firewall filter evaluated by an EX Series switch is the port filter. Understanding this is crucial for managing traffic effectively.

Port filters are applied directly to the physical interfaces of the switch, which means that they have the highest precedence when the switch receives frames. Because these filters operate at the port level, they allow or deny traffic based on the specific characteristics of frames entering through a particular port. This immediate evaluation ensures that any traffic that does not meet the defined criteria is blocked before it has the chance to impact the rest of the network, providing an essential layer of security.

VLAN filters, trunk filters, and route filters each play their own roles in traffic management and security, but they do so at different layers or in different contexts. VLAN filters work at the VLAN level and can apply broader rules to all ports within the VLAN. Trunk filters, on the other hand, apply to all VLANs traversing a trunk link and determine which VLANs are allowed on that trunk. Route filters are associated with routing protocols and control which routes are advertised or accepted based on policy. While all these filters are necessary for holistic network security, the port filter is the first line of defense and processing for frames entering the switch.