IP Services // Lesson 02

Network Time Protocol.

Configure and verify NTP client and server relationships so logs, certificates and operations share trustworthy time.

NTP clientNTP serverStratumClock sourceVerification
01 // Mental model

Start with the big picture.

Correlated logs, certificate validation, automation and troubleshooting all depend on consistent clocks.

CCNA focus: Confirm IP reachability first, then inspect association reach, selected peer and synchronisation status. NTP may need several exchanges before becoming synchronised.
02 // Building blocks

Know what each part does.

01

Why time matters

Correlated logs, certificate validation, automation and troubleshooting all depend on consistent clocks.

02

Client

Synchronises its system clock to one or more configured NTP servers.

03

Server

Provides time to downstream clients; a router can also use its local clock as a reference for a lab.

04

Stratum

Represents distance from a reference clock; it is not a simple accuracy score.

03 // Compare and recognise

Read the clues.

ItemWhat to remember
ntp serverPoints the device at a preferred time source.
ntp masterMakes the local device an NTP server using its own clock; use carefully.
show ntp associationsDisplays peers, reachability and the selected source.
show clock detailShows the device time and source information.
04 // Client and server example

Client and server example.

CORE(config)# ntp master 4
EDGE(config)# ntp server 10.0.0.1 prefer
EDGE# show ntp associations
EDGE# show ntp status
EDGE# show clock detail

Read the example from top to bottom, then verify the resulting state. Configuration is only complete when the output matches the intended design.

05 // Exam and troubleshooting

Turn facts into a method.

  • Points the device at a preferred time source.
  • Makes the local device an NTP server using its own clock; use carefully.
  • Displays peers, reachability and the selected source.
  • Shows the device time and source information.
Exam checkpoint: Confirm IP reachability first, then inspect association reach, selected peer and synchronisation status. NTP may need several exchanges before becoming synchronised.
06 // Check yourself

Network Time Protocol quiz.

1. Why is consistent time especially useful during troubleshooting?

2. Which command points IOS at an NTP source?

3. What does NTP stratum describe?

4. Which command shows NTP peers and reachability?

5. Can synchronisation take time after configuration?

Score: 0 / 5