AdvancedPublished 2026-07-04
NTP Troubleshooting Capstone
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Lab 10 of 10 in NTP & Network Time · ← Previous
CCNA exam domain: IP Services
Advanced NTP capstone, run as a fault hunt. Two branch routers disagree about the time and neither will sync, despite both being configured for NTP and able to ping each other. You get symptoms and the required end state — no fault list. Faults sit on both devices, and two of them make NTP fail while the configuration reads as though it should work — including a restriction pointing at something that was never created.
Learning objectives
- Diagnose an NTP association that never reaches synchronised state, from operational state alone
- Recognise that an access-group referencing an undefined ACL denies everything rather than permitting it
- Understand why demanding authentication without a configured key stops a client trusting any server
- Distinguish a client pointed at the wrong address from a server that is refusing to serve
- Repair faults on both ends of a client/server relationship
Troubleshooting focus
- R2 shows unsynchronized status and never transitions to a valid stratum
- NTP associations indicate an unreachable or invalid server
- A time source exists on-link but is not authoritative
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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.
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