Cisco CCNA mock exam questions sample test – Question 261

.You have a router that is not syncing with its configured time source.
Which of the following is NOT a potential reason for this problem?

A. The reported stratum of the time source is 12
B. The IP address configured for the time source is incorrect
C. NTP authentication is failing
D. There is an access list that blocks port 123

Correct Answer: A

Explanation:
A reported stratum of 12 will not cause a router’s inability to synchronize with its configured time source. The stratum value describes the device’s distance from the clock source,
measured in NTP server hops. When a router reports a stratum value over 15, it is considered unsynchronized. Therefore, a report of 12 could be normal.
The other options describe potential reasons for a lack of synchronization.
When you are configuring the local router with a time source, if the IP address configured for the time source is incorrect, then no synchronization will occur.
If NTP authentication is configured between the local router and its time source, and that process is failing (for example, due to a non-matching key or hashing algorithm), then
synchronization will not occur.
If there were an access list applied to any interface in the path between the local router and its time source that blocks port 123 (the port used for NTP), then synchronization will not
occur.
Objective:
Infrastructure Services
Sub-Objective:
Configure and verify NTP operating in a client/server mode
References:
Cisco > Support > Product Support > Switches > Cisco Nexus 6000 Series Switches > Configure > Configuration Guides > Cisco Nexus 6000 Series NX-OS System Management
Configuration Guide, Release 7.x > Chapter: Configuring NTP