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

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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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                                      • scottalanmillerS
                                        scottalanmiller
                                        last edited by

                                        3:20am .... calling it a night.

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                                        • IT-ADMINI
                                          IT-ADMIN
                                          last edited by

                                          this is DC1 ip setting :

                                          0_1455088634499_2016-02-10_101609.png

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                                          • scottalanmillerS
                                            scottalanmiller
                                            last edited by

                                            If you have a second DC, the secondary DNS should point there rather than to the gateway.

                                            DashrenderD 1 Reply Last reply Reply Quote 1
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