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BeginnerPublished 2026-07-04

CCNA NTP: Authoritative Master and Stratum

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Configure a Cisco IOS router as an authoritative NTP master at a chosen stratum and point a neighbor at it as a client. Understand how NTP stratum works and verify deterministically using show commands rather than waiting for live synchronization.

Track
Est. time
25 minutes
Difficulty
Beginner
Topics

Learning objectives

  • Configure an IOS router as an authoritative NTP master using 'ntp master <stratum>'
  • Configure an IOS router as an NTP client of a specific server using 'ntp server <ip>'
  • Explain NTP stratum and why clients sync at one stratum higher than their source
  • Verify NTP state with 'show ntp status' and 'show ntp associations' without relying on real-time convergence

Troubleshooting focus

  • Client points to the wrong server IP or cannot reach it
  • Authoritative master not configured or configured with the wrong stratum
  • Interface down or mismatched addressing preventing NTP reachability
  • Misinterpreting 'show ntp status' during the initial unsynchronized period

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Grade your work

How this lab is graded
  • Build it your way. Where a lab lets you choose a value — a VLAN name, an interface description — grading checks that you configured it, not which name you picked. Names that another line has to reference, like an ACL applied with access-class, are stated in the guide and do have to match.
  • Addresses, modes and protocol keywords are exact. An IP address, a subnet mask, switchport mode trunk, an encapsulation — these carry the meaning of the lab, so they are graded as written in the guide.
  • Grading reads your saved configuration. Export the lab from CML after you have configured it, and make sure anything you set is in the running-config — a change that only exists in a terminal session never reaches the grader.
  • You can submit as many times as you like. Your best score stands, and each attempt tells you which checks passed so you can work the gaps.
  • Scored something you believe is correct? Use Report an issue on this page — that is exactly how the grading fixes in the changelog got found.

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