Ccna certification Practice Tests

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Appendix 

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  Answers to Practice Test Questions

 34.  A.  Since both routes are default routes, the route with the lowest administrative distance 

(AD) will be selected. The route with the highest administrative distance will never be 

selected first. The route with the lowest metric will only be used if two routes exist to 

the same destination network and have equal administrative distances. The RIP routing 

protocol has an administrative distance of 120; therefore, it has a higher administrative 

distance over a statically defined default route and will not be selected.

 35.  C.  A host route is used when you need to route packets to a different next hop for a 

specific host. A host route is configured as a long prefix of /32 so that it is selected when 

network prefixes are overlapped. The route table will not create host routes; host routes 

must be manually configured by the administrator. Hot Standby Router Protocol (HSRP) 

is not used with host routes, and therefore, it is an incorrect answer.

 36.  B.  The routing protocol code is in the form of a single letter at the beginning of each route 

statement. A legend that depicts each route source precedes the route table. The prefix 

and network mask are learned from the route source. The metric will not identify where 

a route was learned, such as its route source. The next hop will not identify where a route 

was learned, such as its route source.

 37.  B.  All routing decisions are based upon the destination IP address. The router examines 

the IP address and routes the packet to the next closest hop for the network it  

belongs to. The source IP address is not used during the route process and will not 

change throughout the process. The time to live (TTL) is used to limit how many times a  

packet is routed throughout a network or the Internet. The TTL is decremented by 1 as 

it passes through a router; when it reaches 0, the packet will be dropped and no longer 

routable. The destination MAC address is not used for routing decisions.

 38.  C.  Static routing requires a network administrator to intervene and create a route in 

the routing table. Dynamic routing is the opposite of static routing because routes are 

learned dynamically. Link-state and distance-vector routing are forms of dynamic routing 

protocols and do not require administrator intervention.

 39.  A.  The subnet mask is used by the host to determine the immediate network and the 

destination network. It then decides to either route the packet or try to deliver the packet 

itself without the router’s help. The subnet mask of the destination network is not used 

to determine routing decisions because the sending host does not know the destination 

subnet mask. The router does not use the network mask for routing decisions because it is 

not transmitted in the IP packet. The destination computer will check only the destination 

IP address in the packet because the network mask is not transmitted with the IP packet.

 40.  C.  The Address Resolution Protocol (ARP) is employed by the host or router when a 

packet is determined to be local on one of its interfaces. The Internet Group Management 

Protocol (IGMP) is used to build multicast sessions for switches and routers. Reverse 

Address Resolution Protocol (RARP) is used to obtain an IP address assigned for a specific 

MAC address. RARP has been replaced with DHCP and is no longer used outside of 

networking theory. The Internet Control Message Protocol (ICMP) protocol is used with 

connectivity tools such as ping and tracert. ICMP is also used to notify a sender when the 

destination network is unreachable.

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Chapter 3: IP Connectivity (Domain 3)