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  • Modification of IP scheme

    Last year we have split from our parent company and our IT infrastructure was revamped by an IT consultant. They have designed our small network as shown in the diagram

    The IP scheme is given below :

    All workstations with IP address 10.30.10.100/ 24 to 10.30.10.199 / 24
    All Servers IP – 10.30.10.1 / 24 to 10.30.10.20 /24
    All Printers IP – 10.30.10.200 /24 – 10.30.10.215 /24
    All Network devices – 10.30.10.220 / 24 – 10.30.10.235 / 24

    They have setup our DHCP configuration as follows:

    DHCP Server has only 1 Scope setup as
    Start IP 10.30.10.100
    End IP 10.30.10.199
    Scope Options
    003 Router – 10.30.10.254 ie our Firewall
    006 DNS – 10.30.10.1, 10.30.10.2 ( Internal DNS) & 210.55.105.193, 210.55.230.1 ( ISP DNS)

    Initially all clients were obtaining Dynamic IP but later on for keeping a track of users we implemented IP Reservation based on MAC address.

    Since then we are growing and it seems that in another few months I will run out of IP.

    As our DHCP Scope is setup with starting IP as 10.30.10.100, I can still utilise the unused IP address in the range of 10.30.10.21 /24 to 10.30.10.99 and this will keep me running for a while.

    However, I want to implement a scheme that can grow and do not have to bother for a long time.

    Our parent company earlier used 10.30.x.x / 16. As this was class B address this could have grown without any problem. Had our IT consultant used similar 10.30.x.x / 16 IP scheme then probably we would not have faced this problem.

    Our Domain Controller DC 1 is installed as a Virtual Server on HP Blade and DC 2 is a physical Server on Dell Hardware. I do not want to change the IP address of the Servers unless there are no other options.

    I have read about Superscope but not sure how to implement and also no clue whether that is a good option for scalability.

    Could you experts in the forum kindly give your valued suggestions.

    Cheers,

    Pankajb
    Attached Files

  • #2
    Re: Modification of IP scheme

    Strange way of working your network but hey if it keeps you happy. You can keep track of who has what IP using the DHCP MMC or even simple ping.

    How much growth do you intend to see that make you need more than 254 hosts??? You currently have room for around 202 hosts.

    20 IP's for servers - Do you really need 20???
    16 IP's for printers - Do you really need 16???
    16 IP's for Network devices - Do you really need 16???

    You could probably use whats called CIDR (Classless Inter Domian Routing) and borrow a bit from the network mask and have is 10.30.10.0/23 which will give you 510 available hosts

    IP Address : 10.30.10.100
    Address Class : Classless /23
    Network Address : 10.30.10.0

    Subnet Address : 10.30.10.0
    Subnet Mask : 255.255.254.0
    Subnet bit mask : nnnnnnnn.nnnnnnnn.nnnnnnnh.hhhhhhhh
    Subnet Bits : 23
    Host Bits : 9
    Possible Number of Subnets : 1
    Hosts per Subnet : 510

    Comment


    • #3
      Re: Modification of IP scheme

      Dear wullieb1,
      Many thanks for your reply and suggestion.


      20 IP's for servers - Do you really need 20???
      16 IP's for printers - Do you really need 16???
      16 IP's for Network devices - Do you really need 16???
      To be honest I do not anticipate such a growth but no harm in keeping those 20+16+16 = 52 IPs reserved.

      Last year we were around 30 staff team which has now become more than 50 staff so the growth nearly double. We expect to have more than 75 staff by the end of next year.

      Our IT team is also growing and we have Developers who requires to play around with Virtual Machines and that requires additonal IP address. So you can see that my fear is justified.

      You suggested to implement CIDR. Last two days I have been reading about it on the net. Few posting mentioned that we require a router that supports CIDR. Please correct me if I am wrong.

      Also, we would have to change the IP address of the Servers which I am also worried about, primarily the Domain Controllers, DNS, DHCP scope etc.

      If we have to buy a router then why not keep the IP of the Servers intact, have the rest of the LAN on a different network and configure the router accordingly.

      Possibly have two subnets ie one for various department users and other for the IT User.

      Kindly excuse me for talking all theories with no practical experience on implementing a subnet or CIDR. .

      Please give your valued suggestion and opinion again.


      Cheers,

      Pankajb

      Comment


      • #4
        Re: Modification of IP scheme

        What is the worry about changing the IP of the Servers?
        1 1 was a racehorse.
        2 2 was 1 2.
        1 1 1 1 race 1 day,
        2 2 1 1 2

        Comment


        • #5
          Re: Modification of IP scheme

          Originally posted by pankajb View Post
          Dear wullieb1,
          Many thanks for your reply and suggestion.


          To be honest I do not anticipate such a growth but no harm in keeping those 20+16+16 = 52 IPs reserved.

          Last year we were around 30 staff team which has now become more than 50 staff so the growth nearly double. We expect to have more than 75 staff by the end of next year.

          Our IT team is also growing and we have Developers who requires to play around with Virtual Machines and that requires additonal IP address. So you can see that my fear is justified.

          You suggested to implement CIDR. Last two days I have been reading about it on the net. Few posting mentioned that we require a router that supports CIDR. Please correct me if I am wrong.

          Also, we would have to change the IP address of the Servers which I am also worried about, primarily the Domain Controllers, DNS, DHCP scope etc.

          If we have to buy a router then why not keep the IP of the Servers intact, have the rest of the LAN on a different network and configure the router accordingly.

          Possibly have two subnets ie one for various department users and other for the IT User.

          Kindly excuse me for talking all theories with no practical experience on implementing a subnet or CIDR. .

          Please give your valued suggestion and opinion again.


          Cheers,

          Pankajb
          Going from what you have written in your reply you really don't need to change anything.

          At the moment you have available to you 254 hosts on a class c network.

          You want to reserve 52 of these addresses which leaves you with 202.

          You anticipate approx 75 staff to be onsite, lets grab 100, leaves you with 102 addresses that you can use. Thats loads of addresses for your developers.

          You could, depending on your switches, setup what is called a VLAN. You would have 2 of these. One for servers and the other for clients.

          It sounds to me like your trying to make your network a lot more complicate than you need to.

          Comment


          • #6
            Re: Modification of IP scheme

            biggles77 quoted :

            What is the worry about changing the IP of the Servers?
            As mentioned earlier that there has been a revamp and restructuring of our company and thus all our old IT staff are not working here anymore.

            After we disconnected our link with our parent company, the Domain Controller & File Servers were setup by our IT consultant on a HP Blade with HP Aio 1200 SAN. The Servers are actually VMs on XenServer and we are not familiar with changing the Network setup on the Blade ie HP Network Teaming Virtual Miniport Driver etc.

            There are few other Web Servers and DB Servers that are communicating with each others and since we have new developers they are yet to figure out if there are any coding done that communicates with IP.

            I do not have any idea what are the ramifications on changing the IP scheme on the Domain Controllers ie changing the IP and subnet mask. Thus, I was skeptical on changing IP address on the Servers

            wullieb1 quoted:
            It sounds to me like your trying to make your network a lot more complicate than you need to.
            Thanks wullieb1 for waking me up. I think you are right. I am getting unnecessarily worried and making things complicated. It would be easy to change the Scope with a new Start IP Address and End IP Address and live happily for a long time.

            Kindly give a final suggestion on changing the DHCP Scope as I haven’t done it earlier. Do I have to deactivate the Scope before changing it or it can be done while the DHCP scope is active. What are the precautions, if any.


            Many thanks for your opinion.

            Cheers,

            Pankajb

            Comment


            • #7
              Re: Modification of IP scheme

              Originally posted by pankajb View Post
              Thanks wullieb1 for waking me up. I think you are right. I am getting unnecessarily worried and making things complicated. It would be easy to change the Scope with a new Start IP Address and End IP Address and live happily for a long time.

              Kindly give a final suggestion on changing the DHCP Scope as I haven’t done it earlier. Do I have to deactivate the Scope before changing it or it can be done while the DHCP scope is active. What are the precautions, if any.


              Many thanks for your opinion.

              Cheers,

              Pankajb
              Pankajb,

              Leave you DHCP scope as it is and just map it out as you have it at the moment.

              Comment


              • #8
                Re: Modification of IP scheme

                Wullieb 1 quoted:

                Leave you DHCP scope as it is and just map it out as you have it at the moment.
                I am assuming that you wanted me leave the existing scope as it is and map new scope as following:
                Scope 1
                Start IP 10.30.10.21
                End IP 10.30.10.99


                Scope 2
                Start IP 10.30.10.201
                End IP 10.30.10.254
                Exclusion range IP for Printers and Network Devices


                Please correct me if I misunderstood your suggestion.

                Alternatively, are there any issues if I modify the existing scope as follows:

                Scope 0
                Start IP 10.30.10.21
                End IP 10.30.10.254
                Exclusion range IP for Printers and Network Devices

                Once again, thanks a million for all your suggestions.

                Cheers,
                Pankajb

                Comment


                • #9
                  Re: Modification of IP scheme

                  Let me get a DHCP scope configured on a test machine for you and show you screenshots of what i think your scope should look like.

                  Comment


                  • #10
                    Re: Modification of IP scheme

                    Hi Wullieb1,
                    Sorry to bother if you are very occupied.

                    Just thought of letting you know that I will be waiting to get the screenshots from you, whenever you have time to set your test machine.

                    Cheers,

                    Pankajb

                    Comment


                    • #11
                      Re: Modification of IP scheme

                      Create a Scope, 10.30.10.1 - 10.30.10.254
                      Add an Exclusion range (or Exclusion ranges) to exclude any static IPs you want to use for Serves or Reservations for network Printers, etc. Anything left over will be for Dynamic IPs.

                      Don't forget to Authorise the Scope and disable any other DHCP servers on the network.

                      If you are not sure, create a Virtual Server and create a DHCP Server on that to practice with. You will learn more by trying it yourseld than by waiting for someone else to do for you. Once you have tried it in a VM, then come back with any additional questions or problems you may have found.
                      Last edited by biggles77; 24th October 2008, 14:12.
                      1 1 was a racehorse.
                      2 2 was 1 2.
                      1 1 1 1 race 1 day,
                      2 2 1 1 2

                      Comment


                      • #12
                        Re: Modification of IP scheme

                        Originally posted by biggles77 View Post
                        Create a Scope, 10.30.10.1 - 10.30.10.254
                        Add an Exclusion range (or Exclusion ranges) to exclude any static IPs you want to use for Serves or Reservations for network Printers, etc. Anything left over will be for Dynamic IPs.

                        Don't forget to Authorise the Scope and disable any other DHCP servers on the network.

                        If you are not sure, create a Virtual Server and create a DHCP Server on that to practice with. You will learn more by trying it yourseld than by waiting for someone else to do for you. Once you have tried it in a VM, then come back with any additional questions or problems you may have found.
                        Thst pretty much the steps.

                        Sorry but i haven't gotten round to it yet.

                        Comment

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