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Show ntp associations

As explained in Acing the CCNA Exam: Volume 2 Advanced Networking and Security

show ntp associations is a Cisco IOS EXEC command that displays configured NTP servers and their synchronization status and attributes.

show ntp associations verifies a Cisco IOS device’s configured NTP time sources and shows which source currently supplies synchronized time. section 2.3.1 section 2.4

Read the output by focusing on these exam-relevant fields and markers:

  • address identifies the NTP server; ref clock identifies that server’s time source; st shows its NTP stratum. section 2.3.1
  • * marks the selected sys.peer, while + marks a reliable candidate that is not currently selected. section 2.3.1
  • A prefer setting increases the likelihood of selection but does not override factors such as lower stratum. section 2.3.1

Verify two configured servers

After configuring ntp server 216.239.35.0 prefer and ntp server 20.43.94.199, run do show ntp associations. The output marks Google’s server *~ and sys.peer, and Microsoft’s server +~ and candidate. Use show ntp status separately to verify the device’s synchronization state and stratum.

How Acing the CCNA Exam: Volume 2 Advanced Networking and Security covers it

How deep it goes
Explains key columns and selection markers, but defers detailed interpretation of most remaining output fields.
Examples
Uses two configured servers, preferred-server selection, annotated association output, and a separate synchronization-status check.
What it assumes
Assumes NTP client configuration and basic familiarity with servers, reference clocks, and stratum.
What you can do after
Diagnose NTP source selection by identifying configured servers, the active peer, candidate sources, and displayed stratum.
How it connects
Connects NTP client mode, server selection, stratum, reference clocks, and show ntp status.
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Related concepts

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