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  • problems with dhcp and dns

    Hello all:

    A little History:

    I have a 2000 server running and it was the only DNS/DHCP/AD running. So i created 2 new 2003 R2 DC/DHCP/AD.

    I ran dcpromo on both and promoted them and they are now on line with along with the 2k server.

    The problem i am having is when i take the 2k box off line the other 2 DC/AD/DHCP do not kick in. I have to manually disable network card and restart DHCP as it is not running

    The only errors i get are netlogon once the disconnect from network.

    the setup is like this

    win2k server = abc.com
    1 2003 server = abc1.com
    2 2003 server = abc2.com

    I have DHCP setup on all 3 DC and the scopes are scope0, scope1, scope2 all scopes are configured the same way with excluded ip address ranges.

    on the win2k box the primary DNS is itself then abc1.com and abc2.com
    on first 2003 box Primary is itself then abc2.com and then abc.com
    on second 2003 box primary is itself then abc1 and then abc.com

    All three at the moment are global catalogs and DHCP is set to dynamic updates

    All servers Replicate to each other.

    So if i take abc.com off then the network it appears that the network will continue to run with no interruptions but if i take either abc1.com or abc2.com off line at the same time then everything comes to a standstill and the server that is left the DHCP shows not running and no errors in the event viewer except for netlogon failure. Then if i disable and re-able the nectwork card everything starts back up

    any suggestions would be greatly appreciated

  • #2
    Re: problems with dhcp and dns

    why do you have DHCP running on all three? are you trying to create a redundant DHCP scheme?
    its easier to beg forgiveness than ask permission.
    Give karma where karma is due...

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    • #3
      Re: problems with dhcp and dns

      Yes i am trying to setup a redundant system where if the main dc shuts down or goes off line than the next DC in line will take over and continue issuing DHCP and act as if the main one is still running. and if the second DC goes down than the third one goes takes over

      My plan was to create a redundant system as i will be away for approx. 2 weeks and there is no one around to do any computer related server work.

      I have i set this up the wrong way.

      Also in a 2003 server invironment can they all be primary or do the 2 new 2003 server be set to secondary

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      • #4
        Re: problems with dhcp and dns

        you could do a couple of things to ensure redundancy with your DHCP...

        you could cluster the DHCP servers and use one address for clients. if one fails, the other would still be available. i dont think this is an option for your situation with the way you described your network.

        the other option is to use the 80/20 rule. this has one DHCP serving addresses to about 80% of the clients, with a second giving the other 20% of addresses to another set of clients. DHCP doesnt utilized a shared table to prevent clients from receiving the same address, so you have to pay attention to prevent that by carefully defining the scopes.
        http://www.microsoft.com/technet/pro....mspx?mfr=true

        Also in a 2003 server invironment can they all be primary or do the 2 new 2003 server be set to secondary
        you mean DNS now, right? here is Best practices for DNS client settings in Windows 2000 Server and in Windows Server 2003

        if you have a primary and a secondary, then there will be some fault tolerance already. if the primary fails to respond, then the client will switch to the second listed DNS server until either: it quits responding OR the default time period of 15 minutes is reached.

        does that answer all your questions?
        its easier to beg forgiveness than ask permission.
        Give karma where karma is due...

        Comment


        • #5
          Re: problems with dhcp and dns

          So then if i understand these links and what you have said i should be able to create 3 scopes 1 on each DHCP server and excluded a different DHCP range on each server along with excluding the same static range on each DNS server

          Comment


          • #6
            Re: problems with dhcp and dns

            The 80/20 rule is nice unless you're scope is big enough or you can put up the failed DHCP server within a few hours.

            Have a read on this: Conflict detection is quite interesting.
            http://www.windowsnetworking.com/kba...ilability.html
            http://www.windowsdevcenter.com/pub/...CP_Server.html
            Marcel
            Technical Consultant
            Netherlands
            http://www.phetios.com
            http://blog.nessus.nl

            MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
            "No matter how secure, there is always the human factor."

            "Enjoy life today, tomorrow may never come."
            "If you're going through hell, keep going. ~Winston Churchill"

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