Correct Answer : Simple Mail Transfer Protocol
Explanation : SMTP or Simple Mail Transfer Protocol is an application layer protocol used to transport e-mails over the Internet. Only 7-bit ASCII codes can be sent using SMTP.
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.