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.)

A.
#

B.
*

C.
.

D.
~

E.
+

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

Cisco: Cisco IOS Basic System Management Command Reference: show ntp associations