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    Additional DC not functioning if the Primary DC is down !!

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    • DashrenderD
      Dashrender @JaredBusch
      last edited by

      @JaredBusch said:

      The preferred DNS server of the network card in your domain controllers should always point to themselves. Well, assuming that you are using standard Windows DNS.

      The alternate should then be the other DC.

      On DC 1
      DNS Preferred: 127.0.0.1
      DNS Alternate: 192.168.1.XX <- IP of DC2

      On DC 2
      DNS Preferred: 127.0.0.1
      DNS Alternate: 192.168.1.XX <- IP of DC1

      I typically point to the other DC for my Preferred DNS, and myself second. This allows for faster booting, but I see reasons for either way.

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      • IT-ADMINI
        IT-ADMIN
        last edited by

        i'm so sorry for this delay, because it is midnight here, so do you think DNS setting make sense even if the DC2 is offline ??

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        • DenisKelleyD
          DenisKelley
          last edited by

          Best explanation regarding this that I've seen. See Jay's response:
          http://community.spiceworks.com/topic/post/4301599

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          • IT-ADMINI
            IT-ADMIN
            last edited by

            let us suppose that DC2 is offline and cannot see DC1 (which is the main reason i want to make DC2 for high availability) how DNS setting make any difference ??

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            • DashrenderD
              Dashrender
              last edited by

              Yes.

              Let's assume DC2 is offline, but you want to see if you can run ADUC on DC2. When you run ADUC it uses DNS to try to open and failes.

              But if you put in 127.0.0.1 as JB suggests, then it will still work, even with the network card unplugged.

              IT-ADMINI 1 Reply Last reply Reply Quote 0
              • IT-ADMINI
                IT-ADMIN @Dashrender
                last edited by IT-ADMIN

                @Dashrender said:

                Yes.

                Let's assume DC2 is offline, but you want to see if you can run ADUC on DC2. When you run ADUC it uses DNS to try to open and failes.

                But if you put in 127.0.0.1 as JB suggests, then it will still work, even with the network card unplugged.

                i tried that, i put the primary DNS as 127.0.0.1 but still cannot open ADUC,

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                • DashrenderD
                  Dashrender
                  last edited by

                  While you had both DCs on the network together, where you able to connect ADUC to DC2?

                  IT-ADMINI 1 Reply Last reply Reply Quote 0
                  • IT-ADMINI
                    IT-ADMIN
                    last edited by

                    i have a question please : do i have an issue or not, in another word: does DC1 (who has FSMO) should be online in order for DC2 to work properly or it is not a condition ???

                    DashrenderD 1 Reply Last reply Reply Quote 0
                    • IT-ADMINI
                      IT-ADMIN @Dashrender
                      last edited by

                      @Dashrender said:

                      While you had both DCs on the network together, where you able to connect ADUC to DC2?

                      i'm able to open ADUC in DC2 only if DC2 can see DC1, as soon as i unplug DC2 from the network i cannot open ADUC
                      DC2 it is kind of a mirror right now, it is useless, it is nothing without DC1

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                      • DashrenderD
                        Dashrender @IT-ADMIN
                        last edited by

                        @IT-ADMIN said:

                        i have a question please : do i have an issue or not, in another word: does DC1 (who has FSMO) should be online in order for DC2 to work properly or it is not a condition ???

                        That is not a requirement.
                        and because you are having problems when you turn off DC1, it appears that your DC2 is broken.

                        IT-ADMINI 1 Reply Last reply Reply Quote 0
                        • DashrenderD
                          Dashrender @IT-ADMIN
                          last edited by

                          @IT-ADMIN said:

                          @IT-ADMIN 0_1455046058773_2016-02-09_222702.png

                          If possible, please show the above panel for DC1 next to DC2

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                          • IT-ADMINI
                            IT-ADMIN @Dashrender
                            last edited by IT-ADMIN

                            @Dashrender said:

                            @IT-ADMIN said:

                            i have a question please : do i have an issue or not, in another word: does DC1 (who has FSMO) should be online in order for DC2 to work properly or it is not a condition ???

                            That is not a requirement.
                            and because you are having problems when you turn off DC1, it appears that your DC2 is broken.

                            ah now i can see, so i have an issue here, damn glad to know that lol

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                            • IT-ADMINI
                              IT-ADMIN
                              last edited by

                              for the IP setting of DC1, unfortunately i'm home now, but i know its setting very well

                              DC1 :
                              IP : 192.168.15.250
                              Subnet: 255.255.255.0
                              gatway : 192.168.15.1

                              P DNS : 192.168.15.250
                              S DNS : 192.168.15.1

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                              • IT-ADMINI
                                IT-ADMIN
                                last edited by

                                the 2 site are connected via VPN

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                                • DashrenderD
                                  Dashrender
                                  last edited by

                                  OK a possible huge issue is that you are pointing your secondary DNS to x.x.x.1, which is your default gateway, and unless you're using a Domain Controller as a default gateway is a very bad idea.

                                  Windows machines should only ever point to your own DNS servers, more specifically, Windows DNS servers, assuming they are the backbone of your internal network.

                                  If you put something like Google's DNS (8.8.8.8) as a secondary and the machine flips over to using that DNS server, that computer will never find your domain again until it's force to flip back, which will only happen on a reboot or a loss of internet connectivity.

                                  Assuming DC2 is
                                  IP 192.168.1.249
                                  Subnet 255.255.255.0
                                  DF 192.168.1.1
                                  DNS1 192.168.1.249
                                  DNS2 192.168.1.1 (change this to DC1 IP address)

                                  I wonder if your DNS is working on DC2.

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                                  • DashrenderD
                                    Dashrender
                                    last edited by

                                    While both servers are on the network, Open DNS applet. Like ADUC switch to DC2. Check the DNS entries - are they there?
                                    You can open another DNS applet and point it to DC1, then compare. They should be identical.

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                                    • DashrenderD
                                      Dashrender
                                      last edited by

                                      Also, while you're at it, Open a command prompt on DC2 and run dcdiag

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                                      • IT-ADMINI
                                        IT-ADMIN
                                        last edited by

                                        sorry guys, it is 1.35 AM, i have to sleep now
                                        to be continued ...

                                        scottalanmillerS 1 Reply Last reply Reply Quote 1
                                        • scottalanmillerS
                                          scottalanmiller @IT-ADMIN
                                          last edited by

                                          @IT-ADMIN said:

                                          sorry guys, it is 1.35 AM, i have to sleep now
                                          to be continued ...

                                          2:30 am here. Still going.

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

                                            @scottalanmiller said:

                                            @IT-ADMIN said:

                                            sorry guys, it is 1.35 AM, i have to sleep now
                                            to be continued ...

                                            2:30 am here. Still going.

                                            Crazy man.

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