Ccna certification Practice Tests

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Appendix 

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  Answers to Practice Test Questions

 14.  B.  The command 

ntp master configures the router or switch to trust its internal time 

clock. The command 

ntp server is incorrect. The command ntp clock source is 

incorrect. The command 

ntp trusted is incorrect.

 15.  A.  The command 

show clock detail will display either no time source or time 

source is NTP if the router or switch is configured to slave off a server for time. The 

command 

show ntp is incorrect. The command show time is incorrect. The command 

show time source is incorrect.

 16.  C.  The command 

show ntp associations detail will allow you to view the NTP 

clock details from the master NTP server. The command 

show clock detail is 

incorrect. The command 

show ntp detail is incorrect. The command show ntp skew is 

incorrect.

 17.  D.  The Network Time Protocol (NTP) uses UDP port 123 for time synchronization. 

Network Management Protocol (SNMP) uses TCP/161 to listen for incoming SNMP 

messages. TCP/123 can be configured for NTP, but it is normally not used by default. 

UDP/69 is used by Trivial File Transfer (TFTP) for file transfers.

 18.  C.  The command 

debug ntp packets will allow you to verify packets received from 

an NTP server. The command 

show ntp is incorrect. The command show ip ntp is 

incorrect. The command 

debug ntp messages is incorrect.

 19.  A.  A best practice is to configure the main router in your network to a known good 

trusted time source by its DNS address. All devices in your network should then be 

configured to point to this trusted router. All time sources should pyramid out from 

the central source of time in your network. Configuring all devices to a public NTP 

server is not a best practice because multiple firewall entries will need to be configured. 

Configuring all devices to different NTP servers for redundancy is not a best practice 

because all devices should synchronize to the same master. Configuring all devices as 

master servers is not a best practice; only one master should exist.

 20.  C.  The command 

show ntp status will allow you to see the current time source, the 

precision of the time source, and the drift from your internal time clock. The command 

show ntp is incorrect. The command show ip ntp status is incorrect. The command 

debug ntp drift is incorrect.

 21.  B.  The command 

clock timezone pst -8 0 will set the time zone to Pacific Standard 

Time with an offset of –8 from Coordinated Universal Time (UTC) with a minute offset 

of 

0. The command clock timezone pacific is incorrect. The command timezone 

pacific is incorrect. The command timezone pst -8 is incorrect.

 22.  C.  You should configure a loopback interface on the switch with the IP address of the 

NTP server the NTP clients will use. A tunnel interface is an incorrect answer. An NTP 

interface is an incorrect answer. Although a Switched Virtual Interface (SVI) would work, 

it is not active until at least one port is configured with the VLAN. Therefore, the SVI is 

still tied to a physical interface state.

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Chapter 4: IP Services (Domain 4)