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    Best Practice for Time Sync for Active Directory Domain Controllers

    IT Discussion
    windows active directory ntp sntp
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    • DashrenderD
      Dashrender @scottalanmiller
      last edited by

      @scottalanmiller said:

      @coliver said:

      @Dashrender said:

      Soooo what is the BP for setting time in a virtualized environment? Should the VM's get their time from the host OS, or should they pull it direct from an online time source?

      I know with Windows it's a bit more complex.

      Should the PDC emulator pull time from the host server (in my case ESXi - for now) or should it pull from the internet?

      Microsoft recommends that you turn off time synchronization for Domain Controllers. Not sure about generic servers.

      Generic ones get it from the DCs, in those cases.

      Exactly, the rest of the domain will get it's time from the PDC emulator.

      Question, is it OK to shorten PDC emulator to PDCe?

      1 Reply Last reply Reply Quote 0
      • coliverC
        coliver @scottalanmiller
        last edited by

        @scottalanmiller said:

        @coliver said:

        @scottalanmiller said:

        @coliver said:

        @Dashrender said:

        Soooo what is the BP for setting time in a virtualized environment? Should the VM's get their time from the host OS, or should they pull it direct from an online time source?

        I know with Windows it's a bit more complex.

        Should the PDC emulator pull time from the host server (in my case ESXi - for now) or should it pull from the internet?

        Microsoft recommends that you turn off time synchronization for Domain Controllers. Not sure about generic servers.

        Generic ones get it from the DCs, in those cases.

        So would the hypervisors? If that is the case just turning it off for DCs should be enough.

        Only if it is HyperV. Windows doesn't talk NTP.

        That makes sense in the Microsoft kind of way...

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        • DashrenderD
          Dashrender
          last edited by

          I recall when I setup a VM ages ago that VMWare could be the time source for the VMs. I though it was set to work like the BIOS clock.

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          • DashrenderD
            Dashrender
            last edited by

            My current PDC emulator is set to pull time from the BIOS clock

             C:\Windows\system32>w32tm /query /source
             Local CMOS Clock
            

            This hasn't been an issue for years, yet someone called this morning and reported that the phones and the computers didn't match timewise, so I'm looking into it.

            1 Reply Last reply Reply Quote 0
            • scottalanmillerS
              scottalanmiller
              last edited by

              I'm going to turn this into its own topic.

              DashrenderD 1 Reply Last reply Reply Quote 0
              • DashrenderD
                Dashrender @scottalanmiller
                last edited by

                @scottalanmiller said:

                I'm going to turn this into its own topic.

                OK
                🙂

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                • DashrenderD
                  Dashrender
                  last edited by

                  I looked at the settings in ESXi, it was not set to pull time from an external source. I have corrected that, and enabled NTP.

                  ESXi is now correct on it's time, now to force the PDC emulator to sync.. and eventually all windows clients will sync as well.

                  1 Reply Last reply Reply Quote 1
                  • DashrenderD
                    Dashrender
                    last edited by

                    OK tried a

                     w32tm /resync
                    

                    and got back

                     The computer did not resync because no time data was available.
                    
                    coliverC scottalanmillerS 2 Replies Last reply Reply Quote 0
                    • coliverC
                      coliver @Dashrender
                      last edited by

                      @Dashrender said:

                      OK tried a

                       w32tm /resync
                      

                      and got back

                       The computer did not resync because no time data was available.
                      

                      If I remember correctly it actually uses VMWare tools to do the syncing between the computers and the hypervisor.

                      scottalanmillerS 1 Reply Last reply Reply Quote 1
                      • scottalanmillerS
                        scottalanmiller @coliver
                        last edited by

                        @coliver said:

                        @Dashrender said:

                        OK tried a

                         w32tm /resync
                        

                        and got back

                         The computer did not resync because no time data was available.
                        

                        If I remember correctly it actually uses VMWare tools to do the syncing between the computers and the hypervisor.

                        It you are on VMware ESXi, then the VMware tools are the only possible mechanism for that.

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                        • DashrenderD
                          Dashrender
                          last edited by

                          OK, I have VM Tools running - do I just wait and see?

                          scottalanmillerS 1 Reply Last reply Reply Quote 0
                          • scottalanmillerS
                            scottalanmiller @Dashrender
                            last edited by

                            @Dashrender said:

                            OK tried a

                             w32tm /resync
                            

                            and got back

                             The computer did not resync because no time data was available.
                            

                            What time source do you have set? w32tm requires an SNTP source to sync to, what SNTP server do you have it talking to?

                            DashrenderD 1 Reply Last reply Reply Quote 0
                            • DashrenderD
                              Dashrender @scottalanmiller
                              last edited by

                              @scottalanmiller said:

                              @Dashrender said:

                              OK tried a

                               w32tm /resync
                              

                              and got back

                               The computer did not resync because no time data was available.
                              

                              What time source do you have set? w32tm requires an SNTP source to sync to, what SNTP server do you have it talking to?

                              I don't, it's currently pulling from

                               Local CMOS Clock
                              
                              scottalanmillerS 1 Reply Last reply Reply Quote 0
                              • scottalanmillerS
                                scottalanmiller @Dashrender
                                last edited by

                                @Dashrender said:

                                OK, I have VM Tools running - do I just wait and see?

                                There is no sync involved. You are mixing the concepts of NTP/SNTP with a source server and actually controlling the system's clock.

                                1 Reply Last reply Reply Quote 0
                                • scottalanmillerS
                                  scottalanmiller @Dashrender
                                  last edited by

                                  @Dashrender said:

                                  @scottalanmiller said:

                                  @Dashrender said:

                                  OK tried a

                                   w32tm /resync
                                  

                                  and got back

                                   The computer did not resync because no time data was available.
                                  

                                  What time source do you have set? w32tm requires an SNTP source to sync to, what SNTP server do you have it talking to?

                                  I don't, it's currently pulling from

                                   Local CMOS Clock
                                  

                                  Right, which is unrelated to time syncing.

                                  1 Reply Last reply Reply Quote 0
                                  • DashrenderD
                                    Dashrender
                                    last edited by

                                    I'm lost
                                    I said I did this.

                                    @Dashrender said:

                                    My current PDC emulator is set to pull time from the BIOS clock

                                     C:\Windows\system32>w32tm /query /source
                                     Local CMOS Clock
                                    

                                    This hasn't been an issue for years, yet someone called this morning and reported that the phones and the computers didn't match timewise, so I'm looking into it.

                                    So my PDC emulator is pulling time from CMOS. If CMOS changes, won't the OS change too?

                                    1 Reply Last reply Reply Quote 0
                                    • DashrenderD
                                      Dashrender
                                      last edited by

                                      Shouldn't this be in IT discussions? It's technical in nature.

                                      scottalanmillerS 1 Reply Last reply Reply Quote 0
                                      • DashrenderD
                                        Dashrender
                                        last edited by

                                        I guess my desire here was to have the ESXi host be the main source for time inside my network. It of course would pull time from the internet.

                                        It sounds like this isn't going to work. So instead I have to have my PDC emulator pull it's own time from the internet, and the VM Hosts will have to be managed separately.

                                        scottalanmillerS 1 Reply Last reply Reply Quote 0
                                        • DashrenderD
                                          Dashrender
                                          last edited by

                                          Here's the command to set your PDC emulator to sync with a time source

                                            w32tm /config /manualpeerlist: peers /syncfromflags:manual /reliable:yes /update 
                                          

                                          Replace peers with your FQDN or IP of the desired time servers.

                                          1 Reply Last reply Reply Quote 0
                                          • scottalanmillerS
                                            scottalanmiller @Dashrender
                                            last edited by

                                            @Dashrender said:

                                            Shouldn't this be in IT discussions? It's technical in nature.

                                            Hmmm... I didn't choose the category, it just did it.

                                            1 Reply Last reply Reply Quote 0
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