Cisco Cisco Firepower Management Center 4000

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.

Click 

.

Your changes are saved. Note that your changes do not take effect until you apply the device 
configuration; see 

 for more information.

Any

Series 3

After you establish a device cluster, you can configure a physical interface as a high availability (HA) 
link interface. This link acts as a redundant communications channel for sharing health information 
between the clustered devices. When you configure an HA link interface on one device, you 
automatically configure an interface on the second device. You must configure both HA links on the 
same broadcast domain. See 

 for more information.

Dynamic NAT relies on dynamically allocating IP addresses and ports to map to other IP addresses and 
ports. Without an HA link, these mappings are lost in a failover, causing all translated connections to fail 
as they are routed through the now active device in the cluster.

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.

Admin/Network Admin

Select 

.

The Device Management page appears.

Next to the clustered device where you want to configure the HA link interface, click the edit icon (

).

The Interfaces tab for that device appears.

Next to the interface you want to configure as a HA link interface, click the edit icon (

).

The Edit Interface pop-up window appears.

Click 

to display the HA link options.

Select the 

 check box to allow the HA link interface to provide link.

If you clear the check box, the interface becomes disabled and administratively taken down.

From the 

 drop-down list, select an option to designate the link mode or select 

 to 

specify that the interface is configured to autonegotiate speed and duplex settings.

From the 

 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.

Normally, MDI/MDIX is set to 

, which automatically handles switching between MDI and 

MDIX to attain link.