NTP and primary domain controller question

Posted on 2009-04-24
Last Modified: 2013-11-29

I have one question about ntp. We have two DCs. We configured PDC  to sync. with an outside source like it is described in MS article:

I am wondering what happens if PDC fails, or if for some reason ( like restart ) role of primary controller is switched to another DC in domain. What happens with time on client computers.
Ok, they will probably sync with an outside source, by default But is there a way to configure secondary NTP server, I'm not sure is it recommended to configure both DCs to be NTP server.
And if we look at the article above, we can see that configuration of NTP server defer from ''normal'' servers or clients.

Thanks in advance for reply.

Question by:EXOR-ZG
    LVL 6

    Expert Comment

    If the clients can not get the time they will continue to use the time they had. The ntp server really is only there to adjust the time to good source (better one than the internal desktop clock). In other words, ntp is there to adjust the computer clock when it runs too fast/slow - or when you initially install the machine.
    LVL 2

    Expert Comment

    Your clients that are members of your domain will sync time with the domain controller that they authenticated against.  If you change domain controllers, it will be seamless to your clients.  I would configure all your domain controllers to get time from the external source, this way whichever one your clients try to sync with, it will work / and provide accurate time.

    Author Comment

    Ok sfrancy, it's no problem to configure both DCs for NTP, but I didn't found article on the internet that recommends that, or says anything about configuring two ntp servers. So basicly I should setup the other DC in the same way as I did the PDC?
    LVL 2

    Accepted Solution

    Yes, typically your other DC's will sync time with your DC that has the PDC emulator role, but if you want to make sure that your other DC's continue to provide synchronized time in the event your PDC goes down, you can set them all to sync with an external time source.

    In reality though, your DC serving as the PDC emulator would have to be down for a long time before there would be a lot of clock drift on your other DC's.  Hope this all helps.

    Featured Post

    Why You Should Analyze Threat Actor TTPs

    After years of analyzing threat actor behavior, it’s become clear that at any given time there are specific tactics, techniques, and procedures (TTPs) that are particularly prevalent. By analyzing and understanding these TTPs, you can dramatically enhance your security program.

    Join & Write a Comment

    Suggested Solutions

    Title # Comments Views Activity
    iptables and udp ports 23 74
    HP VLAN Routing 16 49
    Understanding NAT and UDP 10 89
    assigning port numbers to web sites and web services 2 59
    A few months ago I attended the Rocky Mountain IPv6 Summit which was a two-day educational event; it was the 3rd annual conference held here in Denver, Colorado that was held at the Hyatt Regency Denver at the Colorado Convention Center. It was an e…
    I know for anybody starting from Beginner to Expert in Networking knows what OSI model. But this tutorial is for freshers or those who are new to networking world. Why I am putting OSI in such simple and compact manner is because it enables you to k…
    After creating this article (, I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
    After creating this article (, I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

    734 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    17 Experts available now in Live!

    Get 1:1 Help Now