Understanding Sensing Interfaces
Sensing interfaces are located on the front of the device. To identify your sensing interfaces, see
Identifying the Sensing Interfaces, page
You can configure a passive deployment to monitor traffic flowing across a network using a switch
SPAN, virtual switch, or mirror port, allowing traffic to be copied from other ports on the switch. Passive
interfaces allow you to inspect traffic within the network without being in the flow of network traffic.
When configured in a passive deployment, the system cannot take certain actions such as blocking or
shaping traffic. Passive interfaces receive all traffic unconditionally and do not retransmit received
You configure an inline deployment transparently on a network segment by binding two ports together.
Inline interfaces allow you to install a device in any network configuration without the configuration of
adjacent network devices. Inline interfaces receive all traffic unconditionally, then retransmit all traffic
received on these interfaces except traffic explicitly dropped. You must assign a pair of inline interfaces
to an inline set before they can handle traffic in an inline deployment.
If you configure an interface as an inline interface, the adjacent port on its NetMod automatically
becomes an inline interface as well to complete the pair.
Configurable bypass inline sets allow you to select how your traffic is handled if your hardware fails
completely (for example, the device loses power). You may determine that connectivity is critical on one
network segment, and, on another network segment, you cannot permit uninspected traffic. Using
configurable bypass inline sets, you can manage the traffic flow of your network traffic in one of the
Configure the inline set as bypass to ensure that traffic continues to flow if your device fails. Configure
the inline set as non-bypass to stop traffic if the device fails. Note that reimaging resets Firepower
devices in bypass mode to a non-bypass configuration and disrupts traffic on your network until you
reconfigure bypass mode. For more information, see the see the Firepower 8000 Series Getting Started
All Firepower devices can contain configurable bypass interfaces. 8000 Series devices can also contain
NetMods with interfaces that cannot be configured for bypass. For more information on NetMods, see
Firepower 8000 Series Modules, page
propagate link state, transparent inline mode, and strict TCP mode. For information on how to configure
your inline interface sets, see Configuring Inline Sets in the Firepower Management Center
Configuration Guide. For more information on using inline interfaces, see
Firepower 8000 Series Hardware Installation Guide
Bypass: an interface pair configured for bypass allows all traffic to flow if the device fails. The
traffic bypasses the device and any inspection or other processing by the device. Bypass allows
uninspected traffic across the network segment, but ensures that the network connectivity is
Non-bypass: an interface pair configured for non-bypass stops all traffic if the device fails. Traffic
that reaches the failed device does not enter the device. Non-bypass does not permit traffic to pass
uninspected, but the network segment loses connectivity if the device fails. Use non-bypass
interfaces in deployment situations where network security is more important than loss of traffic.
2-12. Other advanced interface options include tap mode,
Deploying Firepower Managed Devices
Connecting Devices to Your