Correct Answer : Entire IP packet
Explanation : In the tunnel mode, IPSec adds control bits into the packets to encrypt the entire packet between the IPSec endpoints. Using encryption, it provides secure communication between the two endpoints.
Correct Answer : DUAL
Explanation : EIGRP uses the DUAL algorithm for finding shortest path. DUAL stands for diffusing update algorithm and it is used to prevent routing loops by recalculating routes globally.
Correct Answer : 170
Explanation : Routers use the metric of administrative distance to select the best path when there are different routes to the same destination from two different routing protocols as it is a measure of reliability of routing protocols. Administrative distance for external EIGRP is 170.
Correct Answer : IP default network
Explanation : IP default network command is used to find the default gateway in Cisco router. If the router finds routes to the node, it considers the routes to that node for installation as the gateway to it.
