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  • DNS issue

    we have a 2k3 domain

    one of the servers handles DNS.

    it is configured with forwarders that go out to our ISPs DNS for external DNS resolution.

    our DHCP server is configured to provide DNS address to each client with their lease. so, the first DNS address they are provided (primary DNS) is our internal DNS servers IP address. the secondary DNS provided is our ISPs DNS.

    here is the problem i am having. whenever I nslookup, trying to find an internal address, the client computers dont even try to use the internal DNS server for resolution. it just defaults it to the secondary nameserver.

    C:\Documents and Settings\Owner>nslookup
    *** Can't find server name for address 10.0.2.2: Non-existent domain
    Default Server: xxxx.ourISP.net
    Address: xx.xx.xx.xx

    > internalnode1
    Server: xxxx.ourISP.net
    Address: xx.xx.xx.xx
    *** xxxx.ourISP.net can't find internalnode1: Non-existent domain
    > exit




    i know for sure our internal DNS is functioning for several reasons:
    1. if I type "server 10.0.2.2" into nslookup and then query, i get all of the internal names resolved perfectly fine.
    2. if I go into DHCP, and remove the secondary DNS addresses (of our ISP) from being provided along with the lease, and then ipconfig /release and /renew a client computer, nslookup finds all of the internal addresses perfectly fine.

    but, just for redundancy sake, i dont want to leave the client computers with only our internal DNS without having a failsafe in case it takes a nosedive.

    any ideas on why this would be? especially that initial message that nslookup gives us about not being able to find the name for 10.0.2.2? is it simply because we dont have a RLZ (and thus, no PTR record for the DNS server itself)?

  • #2
    Re: DNS issue

    Without getting into a bunch of gory details, I'll give you two things that will clear this up for you:

    1. Configure a reverse lookup zone for your internal subnet on your internal DNS server.

    2. Don't configure DHCP to assign the ISP's DNS server as a secondary server. All DNS queries (both internal and external) should be handled by your internal DNS server.

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    • #3
      Re: DNS issue

      2. Don't configure DHCP to assign the ISP's DNS server as a secondary server. All DNS queries (both internal and external) should be handled by your internal DNS server.
      Is that standard practice though? Not that I am expecting our DNS server to go down, but in the event that it does- won't not having that secondary DNS address known to each client prevent them from resolving names to IPs?

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      • #4
        Re: DNS issue

        Create a second DNS Server if you are that concerned. ISP DNS entries should be entered in your DNS Forwarders.

        Without knowing the size of your network or the number of Servers, having DNS fail could be a moot point especially if you are only running the one Server.
        1 1 was a racehorse.
        2 2 was 1 2.
        1 1 1 1 race 1 day,
        2 2 1 1 2

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