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Extension practice

NTP Practice Questions

Extension practice: Clock synchronization with the Network Time Protocol.

Author-reviewed by LabFabric · 7 September 2026 · Report a content issue

One solved question, so you can see how these are marked

Which command creates an NTP client-to-server association with 10.0.1.100, rather than symmetric peering?

ntp server 10.0.1.100

ntp server <address> configures the router as an NTP client that polls the specified server to synchronize its clock.

Every question in the set below is marked like this. The answers stay hidden until you pick one.

Find related practice in the CCNA path
All 5 NTP questions in this set

Answers and explanations appear when you work through the set above.

  1. What distinguishes a stratum 1 NTP time server?

    • It is directly connected to an authoritative time source, such as an atomic or GPS clock
    • It has never successfully synchronized to any time source
    • It is exactly 1 hop away from the router requesting time
    • It is a Cisco device acting only as an NTP client, never a server

  2. A router shows 'Clock is unsynchronized, stratum 16, no reference clock' shortly after ntp server is configured. What does stratum 16 indicate here?

    • The router has not yet synchronized and is not usable as a valid time source
    • The router is 16 hops from the configured NTP server
    • The configuration is invalid and must be re-entered
    • The router is functioning as an NTP master at the lowest possible priority

  3. Which command configures a router to act as an NTP server for other devices even if it has no upstream NTP source of its own?

    • ntp master
    • ntp server
    • ntp authenticate
    • ntp update-calendar

  4. A network administrator wants NTP peers to only accept time updates from an authenticated source. Which set of commands lets the client authenticate its server using key 1?

    • ntp authenticate, ntp authentication-key 1 md5 <key>, ntp trusted-key 1, and ntp server <ip> key 1 on the client
    • ntp authenticate and ntp server <ip> only, no key needed
    • ntp trusted-key 1 alone is sufficient on both devices
    • enable secret must match between the two devices, NTP has no separate authentication

  5. After NTP has successfully synchronized a router's clock, what does show clock detail report as the time source?

    • NTP
    • User configuration
    • Calendar
    • Manual