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Which of the following is a show ntp associations command output symbol that indicates that an IP address is an NTP master and the router is synchronized with the master? (Select the best answer.)
- #
- *
- .
- ~
- +
Explanation:
The asterisk (*) is a show ntp associations command output symbol that indicates that an IP address is a Network Time Protocol (NTP) master and the router is synchronized with the master. The output of the show ntp associations command displays the IP addresses of configured NTP servers as well as their respective clock sources, strata, and reachability statistics. For example, in the following command output, the NTP server at IP address 128.227.205.3 is a stratum 1 server that uses a global positioning system (GPS) time source as its time source:
The * next to the IP address in the command output indicates that this server is an NTP master time source to which the Cisco device is synched. The pound sign (#) next to the IP address indicates that this server is an NTP master time source to which the Cisco device is not yet synched. The plus sign (+) next to the IP address indicates that this server is an NTP master time source that is selected for synchronization but the synchronization process has not yet begun. A tilde (~) next to an IP address indicates that the address was manually configured.
The period (.) is a symbol displayed in the output of the show clock command, not the show ntp associations command. If the time is set by a timing source and is not synchronized with that source, the time is still considered authoritative but the . symbol is displayed in the output of the show clock command to indicate the lack of time synchronization. The following command output indicates that the software clock is authoritative but not synchronized with its time source:
.10:06:40.603 UTC Tue Jan 13 2015
The show clock command displays the current time as reported by the system software clock. If the software clock is not set by a timing source, such as NTP, the system will flag the time as not authoritative and the output of the show clock command will indicate the flag with the * symbol, as shown in the following command output:
*10:06:40.603 UTC Tue Jan 13 2015
By contrast, if the time is set by a timing source and is synchronized with that source, the time is considered authoritative and the output of the show clock command will not display any additional symbols. For example, the absence of additional symbols in the following command output indicates that the software clock is authoritative and synchronized with its time source:
10:06:40.603 UTC Tue Jan 13 2015
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