Cisco Certified Internetwork Expert (CCIE) Practice Test

Which statement regarding routing functions of Cisco ASA running software version 9.2 is true?

1. The ASA supports policy-based routing with route maps

2. In a failover pair of ASAs, the standby firewall establishes a peer relationship with OSPF neighbors

3. The translation table cannot override the routing table for new connections

4. Routes to the Null0 interface cannot be configured to black-hole traffic

The correct answer is: Routes to the Null0 interface cannot be configured to black-hole traffic

The statement that routes to the Null0 interface cannot be configured to black-hole traffic is not accurate. In routing, the Null0 interface is commonly used to discard or "black-hole" unwanted traffic. When a route is configured to point to Null0, it effectively signifies that any traffic matching that route should simply be discarded. This is typically utilized to prevent routing loops or to manage unwanted traffic flows. The other statements highlight various aspects of Cisco ASA functionality, but the assertion regarding the Null0 interface specifically addresses its purpose in managing unwanted traffic. In an ASA environment, the Null0 route plays a critical role and can indeed be employed to black-hole traffic, effectively terminating specific pathways without forwarding them. Therefore, understanding the specifics of how the Null0 interface operates allows an individual to manage routing behaviors within the ASA effectively and utilize the interface appropriately when configuring network traffic management strategies.