NTP (Network Time Protocol)


You are the owner of a Swiss watch factory. Time is everything to you and the same applies to your network. You want to make sure that your complete network is synchronized and up-to-date. Now get going since time is money!


  • All IP addresses have been preconfigured for you.
  • EIGRP has been configured for full connectivity.
  • Configure router Planck and Atomic to be NTP Masters, use stratum 10.
  • Make sure router Planck and Atomic synchronize with each other.
  • Router Julian has to check router Planck and Atomic for NTP updates, it has to prefer router Atomic.
  • Configure router Julian so it broadcasts NTP packets on its FastEthernet 1/0 interface.
  • Configure router Century so it configures itself using the NTP broadcast packets from router Julian.
  • Configure router Planck to send NTP packets to multicast address
  • Configure router Millenium to configure itself using the NTP multicast packets.




Network Time Protocol NTP

Video Solution:

Configuration Files

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Written by René Molenaar - CCIE #41726

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About the Author: Rene Molenaar

René - CCIE #41726 is the creator of GNS3Vault.com where he shares CCNA, CCNP and CCIE R&S labs. He also blogs about networking on http://networklessons.com


    1. Great! good to hear it’s useful.

      Cisco has a couple of design guides about NTP on their website. They explain how you should setup NTP on a campus LAN and more…useful stuff if you need to design a network.

  1. I realized that you configured PIM in the multicast section, but I believe that is redundant, because there is no "multicast routing" involved, since we only require a TTL of 1. In this case, such as OSPF or EIGRP, we don’t need to enable PIM to listen to multicast messages.

  2. Hi..

    Am new to this NTP configuration, can any one help me out..?

    Thanks in advance.

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