Ccna certification Practice Tests

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Appendix 

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  Answers to Practice Test Questions

 66.  A.  Network Address Translation (NAT) creates packet switching path delay. This is 

because each address traveling through the NAT process requires lookup time for the 

translation. NAT does not introduce security weaknesses; it can actually be used to 

strengthen security, since private IP addresses are masqueraded behind a public IP address. 

NAT is often used so that address renumbering is not required when two networks 

are merged together with identical IP addressing. NAT does not increase bandwidth 

utilization at all.

 67.  B.  Static Network Address Translation (NAT) is a one-to-one mapping between a local 

(private) and global (public) IP address. This is used for servers, such as web servers 

and email servers, so that they are Internet reachable. Dynamic NAT creates a dynamic 

association between local and global addresses for a specific period of time. NAT 

Overloading, also known as Port Address Translation (PAT), creates a dynamic mapping 

to a pool of IP addresses or an individual IP address using the source and destination ports 

of the packet. Symmetric NAT is NAT Overloading where the source port and destination 

port are mapped to the same matching global source port and destination port.

 68.  B.  The Network Time Protocol (NTP) is used to synchronize time for routers and 

switches. Simple Network Management Protocol (SNMP) is used to transmit and collect 

counters on network devices. Syslog is used to transmit and collect messages from network 

devices. Internet Control Message Protocol (ICMP) is used by many diagnostic tools such 

as ping and traceroute to communicate round trip time and reachability.

 69.  A.  Domain Name Services (DNS) direct queries are performed over the UDP protocol to 

port 53. The queries do not require the TCP setup and teardown because the queries are 

simple request and reply messages, so UDP is used for direct queries. TCP port 53 is used 

for DNS zone transfers between DNS servers. UDP port 55 is not used for any popular 

protocols. UDP port 68 is used with the Dynamic Host Configuration Protocol (DHCP).

 70.  C.  The introduction of SNMP version 2c added the Inform and Get-bulk messages for 

SNMP. SNMP version 1 was the first release of SNMP, and it did not support Inform 

and Get-bulk messages. SNMP version 2 was promptly replaced with SNMP version 2c; 

therefore, it is an invalid answer. SNMP version 3 introduced many new features such as 

security and encryption, to name a few.

 71.  C.  The command 

logging host 192.168.1.6 will configure all logs to be sent to the 

syslog server 192.168.1.6. The command 

logging server 192.168.1.6 is incorrect. 

The command 

logging 192.168.1.6 is incorrect. The command syslog server 

192.168.1.6 is incorrect.

 72.  C.  The command 

ip address dhcp will configure the router to use DHCP for IP address 

assignment. This command needs to be issued on the interface in which you want the 

IP address to be configured, similar to static IP address assignment. The command 

ip 

address dhcp is incorrect, when it is configured in the global configuration prompt. The 

command 

ip address auto is incorrect, regardless of which prompt it is configured in.

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Chapter 8: Practice Exam 2