# Types of traffic inspection interfaces for Layer 2 Firewalls

Capture Interfaces and Inline Interfaces on Layer 2 Firewalls pick up traffic for inspection.

Layer 2 Firewalls inspect network traffic. Layer 2 Firewalls are typically installed inline, directly on the traffic path so that traffic must always pass through the Layer 2 Firewall engine to reach its destination. Only traffic that attempts to pass through Inline Interfaces can be actively filtered.

You can also configure a Layer 2 Firewall in Passive Firewall mode. In Passive Firewall mode, a Layer 2 Firewall has Capture Interfaces defined for inspections that listen to and log network traffic.

Connections picked up through Capture Interfaces can be reset through specially set-up Reset Interfaces. Capture Interfaces and Inline Interfaces can be defined on the same Layer 2 Firewall and used simultaneously.

Logical Interface elements allow you to group interfaces together according to network segment. You can then use the Logical Interface elements as matching criteria when you edit the rules in your Layer 2 Firewall policies.