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  • DNS issue

    I have two active directory servers encsd1 and encsd3. My domain name is encsd.net I have a web site www.encsd.net. ENCSD1 is my primatry DNS server. Here is the problem I cannot resolve www.encsd.net
    I can resolve using my ISP DNS server but cannot resolve from my DNS server. What have I done wrong?
    Last edited by superhl; 20th February 2009, 23:26.

  • #2
    Re: DNS issue

    You could add a CNAME record for www.encsd.net to point to the IP address of the web server. I believe this is just the case of adding it as www and pointing it at the relevant host record.

    As your domain name is encds.net, it will regard itself as authoritative for that domain, so will not use the ISP's DNS servers to resolve the name.

    It resolves from outside as there is probably a firewall rule set to forward requests on the external IP of the firewall to the appropriate internal server hosting the website.
    Last edited by Virtual; 21st February 2009, 01:17.

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    • #3
      Re: DNS issue

      Encsd1 ip address is xxx.xx.xxx.232 and Encsd2 ip address is xxx.xx.xxx.235 both on the same subnet. the ISP DNS name is on a different subnet located outside the firewall and is communicating through firewall with no problems. If on the workstation i assign dns ip address to the ISP ipaddress at the URL type www.encsd.net and page appears. If I change the workstation to the internal DNS of .252 can not resolve web address. At the URL, if I the ip address, webpage appears. Don't really understand the CNAME opton but will research and give it a try.

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      • #4
        Re: DNS issue

        Do some research on split DNS and it will make sense. If you add a CNAME record alled www and point it to the host address that your firewall points at for external users. Therefore, internal users wll go direct to the webserver through the internal IP and won't be routed out on the internet for access.

        DNS works as a hierarchy. It will look at its NS records to see if it is a authoritative for the zone. As you have split DNS, the same name externally and internally, the internal clients when pointing at internal DNS, will contact that one and request the name www.encsd.net to be resolved. When looking at it's NS record, it will see that it is authoritative for the domain. In other words, it will rightly assume that no other DNS can resolve the name and it's its job. It will look for the host (A) record of www and will not find it. As it is authoritative for the domain, it won't use any forwarders, conditional forwarders or root hints to find the I of the website.

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        • #5
          Re: DNS issue

          I have previously completed these steps in the original DNS setup. the bold steps I am not sure about. Can explain that to me. Thanks





          To manage the DNS servers, follow these steps:
          1. Go to Start | All Programs | Administrative Tools | DNS.
          2. Right-click the server name, and choose Properties.
          3. On the Forwarders tab, it should say All Other DNS Domains in the DNS Domain box. This means the server will automatically forward any requests for DNS domains that it doesn't handle to the servers listed in Selected Domain's Forwarder IP Address List.
          4. Add your ISP's DNS servers to this list. Type the server's IP address, and click Add.
          5. Repeat the process for each of your ISP's DNS servers.
          6. When you're finished, click Apply.
          Next, add the appropriate entries to the domain for which you want to add services. Configure this server using the internal NAT IP addresses. Continue to update your ISP's DNS records with the translated or "real" IP add

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          • #6
            Re: DNS issue

            Originally posted by superhl View Post
            I have previously completed these steps in the original DNS setup. the bold steps I am not sure about. Can explain that to me. Thanks

            Next, add the appropriate entries to the domain for which you want to add services. Configure this server using the internal NAT IP addresses. Continue to update your ISP's DNS records with the translated or "real" IP add

            As you no doubt find, all your clients will access other internet sites ok with you having configured the settings.

            The text in bold is a bit misleading. It basically tells you to add records to your internal DNS for any services (such as the website) you want the clients to access. It will be a case of creating the www CNAME record to point to the Host (A) Record of the web server. The internal IP address of the web server would be the NAT IP address. It states to point any ISP DNS records on the ISP server to the external IP address of the firewall or NAT device traffic on that external IP address and NATs it to the internal web server.

            THe "real" IP address must refer to the registered IP address for the domain that is routable on the internet and that has been allocated by the ISP to you.

            If you right click on the domain node in DNS, it should give you a choice of creating a CNAME record.

            Hope this makes sense.

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            • #7
              Re: DNS issue

              Originally posted by Virtual View Post
              It will be a case of creating the www CNAME record to point to the Host (A) Record of the web server.
              Creating a CNAME record will only work if you point it to the hosting company's A record.


              superhl, I would just create an A record on your DNS server and point it to the IP address of your web host's server.

              To add a record, right click the domain folder and then select the record type
              Click image for larger version

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              If you configure a host record you only need to put in www as the name
              Click image for larger version

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              Regards,
              Jeremy

              Network Consultant/Engineer
              Baltimore - Washington area and beyond
              www.gma-cpa.com

              Comment


              • #8
                Re: DNS issue

                I realise that. I must have got the wrong idea. I thought the website was hosted internally, hence my statements below.

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                • #9
                  Re: DNS issue

                  No worries.
                  Regards,
                  Jeremy

                  Network Consultant/Engineer
                  Baltimore - Washington area and beyond
                  www.gma-cpa.com

                  Comment


                  • #10
                    Re: DNS issue

                    I created a hostname , CNAME and link the CNAME to the host. All is working! Thinks for all the great help!!!!!!!

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                    • #11
                      Re: DNS issue

                      No problems. It's a good job Jeremy came along as well. I should have thought about where the website was hosted. Glad it's sorted and thanks Jeremy for your input.

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                      • #12
                        Re: DNS issue

                        Yeah, glad to help.
                        Regards,
                        Jeremy

                        Network Consultant/Engineer
                        Baltimore - Washington area and beyond
                        www.gma-cpa.com

                        Comment

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