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  • DNS problem???

    Hello!

    I have the following situation:

    We have a windows SBS 2003 machine that we use for mail server and webserver.

    On this machine we host our company website www.exemple.com but without nameservers. The nameservers are hosted at another company. Everything works O.k. but randomly, without anything modified at some months interval our employees can't acces the website from the internal network. From an external I.P. everything is O.k. This situation goes on for some days and then they can access again the website from internal network...
    I have the DNS server running on this machine but again, with no use because the nameservers that contains A and MX records are hosted at another company.
    Could this be a problem and the local DNS servers enters in some kind of conflict with external DNS and IT really wants to resolve websites for our internal users???
    Why is this happening randomly and then after some days without any intervention the situation come back to normal???

  • #2
    Re: DNS problem???

    Let my guess, example.com is also the internal name of your Active directory domain?

    The only way to access the web site is with the www, because the domain name
    must resolve to the IP addresses of all Domain Controllers that have file
    sharing enable. This is so the DFS shares, \\name.com\sysvol and
    \\name.com\netlogon are accessible to all domain member clients.
    There is a fairly easy workaround, if you have IIS installed on your DCs,
    you can configure a web site for name.com, then on the Home Directory tab of
    that site, select redirection to a URL and enter http://www.name.com in the
    field that opens. Otherwise, without the DCs redirecting the site, you'll
    have to use www.name.com.

    Common scenario with an easy fix.

    Two choices:

    1. Obtain the IP address of the external web server. Then under your
    mydomain.com zone, right-click, new Host, type in www (without the quotes),
    and provide the IP address you obtained. To allow users to get to it using
    http://mydomain.com (without the www portion), on your DC and every DC (this
    is because of the LdapIpAddress, or the 'same as parent' record), go into
    IIS, under the default website properties, home Directory tab, setup a
    redirect to www.mydomain.com.

    2. Find out who the external authorative name servers are for the domain.
    Then right-click your internal zone mydomain.com, New, Delegation, then
    provide it with a www, then for the name servers, provide the authorative
    name servers you obtained. This will allow for the hosting company to
    occasionally change the webserver's IP address and you will still get to the
    site. Yea, some ISPs do that and don't tell you. You will also need to do
    the redirect explained in Step#1 to make http://mydomain.com work.
    [Powershell]
    Start-DayDream
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    Comment


    • #3
      Re: DNS problem???

      Sorry for not specifying...

      The internal dns server uses exemple.local while the site is exemple.com.

      another problem is that on this server I also have five more websites of other small companies and none of them seems to work from our internal network...From an external ip everything is o.k. This affects only the web sites, not the exchange part...The internal users can connect to exchange with outlook but, of course, not with OWA.
      As I already told this happens randomly without any modification on the webserver, and the problem is solved by miracle after some days...
      The hosted nameservers are O.K., up and running but what happens in the internal network???
      I also randomly receive the message Event Type: Warning

      Event Source: NETLOGON
      Event Category: None
      Event ID: 5781
      Date: 4/21/2008
      Time: 11:21:04 AM
      User: N/A
      Computer: exemple
      Description:
      Dynamic registration or deletion of one or more DNS records associated with DNS domain 'ForestDnsZones.exemple.local.' failed. These records are used by other computers to locate this server as a domain controller (if the specified domain is an Active Directory domain) or as an LDAP server (if the specified domain is an application partition).

      Possible causes of failure include:
      - TCP/IP properties of the network connections of this computer contain wrong IP address(es) of the preferred and alternate DNS servers
      - Specified preferred and alternate DNS servers are not running
      - DNS server(s) primary for the records to be registered is not running
      - Preferred or alternate DNS servers are configured with wrong root hints
      - Parent DNS zone contains incorrect delegation to the child zone authoritative for the DNS records that failed registration

      USER ACTION
      Fix possible misconfiguration(s) specified above and initiate registration or deletion of the DNS records by running 'nltest.exe /dsregdns' from the command prompt or by restarting Net Logon service. Nltest.exe is available in the Microsoft Windows Server Resource Kit CD.

      For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

      Why the computers from the internal network don't use the external nameservers to resolve the website???
      This webserver is not an domain controller for the workstations and it is on a separate domain (exemple.local) from our workstations. We have another fileserver (exemple2.local) that is domain controller for our network but the two servers are not trusted for delegation from security reasons. So both are inside the network but on separate internal domains so why the workstations don't resolve the nameservers externally???

      Comment


      • #4
        Re: DNS problem???

        Have you configured your DNS servers to use forwarding?
        If you do NSLOOKUP to the website what do you get?
        [Powershell]
        Start-DayDream
        Set-Location Malibu Beach
        Get-Drink
        Lay-Back
        Start-Sleep
        ....
        Wake-Up!
        Resume-Service
        Write-Warning
        [/Powershell]

        BLOG: Therealshrimp.blogspot.com

        Comment


        • #5
          Re: DNS problem???

          Originally posted by Killerbe View Post
          Have you configured your DNS servers to use forwarding?
          If you do NSLOOKUP to the website what do you get?
          No, i did not configured forwarding...
          I was thinking that it is not necessary and since for a long period of time everything was o.k....

          nslookup from external ip on one of the hosted websites gives immediate answer pointing to the ip address of our webserver so it is working...

          nslookup from internal network: hmmm, first it gives an error that it can't find server name for addres (and it gives my the internal ip addres of our domain controller that is a fileserver) and then it points to the ip address of the webserver...

          Comment


          • #6
            Re: DNS problem???

            Originally posted by barbacot View Post
            No, i did not configured forwarding...
            I was thinking that it is not necessary and since for a long period of time everything was o.k....

            nslookup from external ip on one of the hosted websites gives immediate answer pointing to the ip address of our webserver so it is working...

            nslookup from internal network: hmmm, first it gives an error that it can't find server name for addres (and it gives my the internal ip addres of our domain controller that is a fileserver) and then it points to the ip address of the webserver...
            Can you place a printscreen?
            [Powershell]
            Start-DayDream
            Set-Location Malibu Beach
            Get-Drink
            Lay-Back
            Start-Sleep
            ....
            Wake-Up!
            Resume-Service
            Write-Warning
            [/Powershell]

            BLOG: Therealshrimp.blogspot.com

            Comment

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