Cisco Cisco Firepower Management Center 4000

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7-2
FireSIGHT System User Guide
 
Chapter 7      Setting Up an IPS Device 
  Configuring Passive Interfaces
Caution
Changing the maximum transmission unit (MTU) interrupts traffic on the device. The range within 
which you can set the MTU can vary depending on the FireSIGHT System device model and interface 
type. See 
 for more information.
To configure a passive interface:
Access: 
Admin/Network Admin
Step 1
Select 
Devices > Device Management
.
The Device Management page appears.
Step 2
Next to the device where you want to configure the passive interface, click the edit icon (
).
The Interfaces tab appears.
Step 3
Next to the interface you want to configure as a passive interface, click the edit icon (
).
The Edit Interface pop-up window appears.
Step 4
Click 
Passive 
to display the passive interface options.
Step 5
Optionally, from the 
Security Zone
 drop-down list, select an existing security zone or select 
New
 to add a 
new security zone.
Step 6
Select the 
Enabled
 check box to allow the passive interface to monitor traffic.
If you clear the check box, the interface becomes disabled so that users cannot access it for security 
purposes.
Step 7
From the 
Mode
 drop-down list, select an option to designate the link mode or select 
Autonegotiation
 to 
specify that the interface is configured to automatically negotiate speed and duplex settings. Note that 
mode settings are available only for copper interfaces.
Note
Interfaces on 8000 Series appliances do not support half-duplex options. 
Step 8
From the 
MDI/MDIX
 drop-down list, select an option to designate whether the interface is configured for 
MDI (medium dependent interface), MDIX (medium dependent interface crossover), or Auto-MDIX. 
Note that MDI/MDIX settings are available only for copper interfaces.
By default, MDI/MDIX is set to 
Auto-MDIX
, which automatically handles switching between MDI and 
MDIX to attain link.
Step 9
In the 
MTU
 field, type a maximum transmission unit (MTU), which designates the largest size packet 
allowed.
The range within which you can set the MTU can vary depending on the FireSIGHT System device 
model and interface type. See 
 for more information.
Step 10
Click 
Save
.
The passive interface is configured. Note that your changes do not take effect until you apply the device 
configuration; see 
 for more information.