Cisco Cisco Firepower Management Center 2000

You can configure logical hybrid interfaces on managed devices that allow the FireSIGHT System to 
bridge traffic between virtual routers and virtual switches. If IP traffic received on interfaces in a virtual 
switch is addressed to the MAC address of an associated hybrid logical interface, the system handles it 
as Layer 3 traffic and either routes or responds to the traffic depending on the destination IP address. If 
the system receives any other traffic, it handles it as Layer 2 traffic and switches it appropriately. You 
cannot configure logical hybrid interfaces on a virtual managed device or Sourcefire Software for  
X-Series.

Note that hybrid interfaces that are not associated with both a virtual switch and a virtual router are not 
available for routing, and do not generate or respond to traffic.

For more information about setting up hybrid interfaces, see 

.

Control

Series 3

You must associate a logical hybrid interface with a virtual router and virtual switch to bridge traffic 
between Layer 2 and Layer 3. You can only associate a single hybrid interface with a virtual switch. 
However, you can associate multiple hybrid interfaces with a virtual router.

You can also configure SFRP on a logical hybrid interface. See 

 for more 

information.

Note that disabling the 

 option for hybrid interfaces does not prevent ICMP 

responses in all scenarios. You can add rules to an access control policy to drop packets where the 
destination IP is the hybrid interface’s IP and the protocol is ICMP. For more information about creating 
access control rules, see 

. If you have 

enabled the 

 option on the managed device, it drops the packets before they 

reach the host, thereby preventing any response. For more information about inspecting local router 
traffic, see 

.

Changing the maximum transmission unit (MTU) interrupts routed or switched traffic on the device and 
packets are dropped. The range within which you can set the MTU can vary depending on the FireSIGHT 
System device model and interface type. See 

more information.