DHCP Superscope

Discussion in 'Server Networking' started by ITCOM, Sep 1, 2006.

  1. ITCOM

    ITCOM Guest

    Dear All
    We will create supersscope in our DHCP server, but some question cannot
    solve out by me. I need clear to know the after implement to.,

    W2003 DC IP: /
    10.5.1.x -
    172.10.1.x - (LAN1)
    172.20.1.x - (LAN 2)

    For 10.5.1.x for Server / IT equipment network
    For 172.10.1.x for another Floor use network

    Only one DHCP locate in 10.5.1.X network.

    - In DHCP server, how setup from LAN2 IP can be alloacte to 172.10.1.x DHCP
    ip range.

    ITCOM, Sep 1, 2006
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  2. That is not what Superscopes are for.
    Get rid of it.
    Superscopes are for Multi-netting,....you are not Multi-netting.

    User one separate distinct scope for each Segment. Configure the LAN Router
    to pass DHCP Queries to the DHCP Server. That is all,...there is nothing
    else. It does not matter where the DHCP Server is or what IP# it uses
    Phillip Windell, Sep 1, 2006
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  3. In
    I agree. Besides with that /8 ( subnet for, it
    encompasses the whole class A subnet, so a superscope would be

    Ace Fekay [MVP], Sep 1, 2006
  4. Ah!
    I didn't notice that part. That should be trimmed down to 24bit. You know
    how I'm always preaching to keep segments below 300 hosts :)

    Phillip Windell [MCP, MVP, CCNA]
    Phillip Windell, Sep 1, 2006
  5. ITCOM

    ITCOM Guest

    Thanks information.
    That mean is if using superscope the IP should be using

    DHCP Supercope /
    LAN 1: /
    LAN 2: /

    Please advice
    ITCOM, Sep 4, 2006
  6. ITCOM

    ITCOM Guest

    you mean is the DHCP Supercope setup as , under supoercope each
    subnet setup

    LAN 1: -
    LAN 2: -
    LAN 3: -
    LAN 4: -
    .. . .

    If this correc, i will try impletement on my testing server

    ITCOM, Sep 4, 2006
  7. In
    No. Those two subnets you indicated are already on the SAME SUBNET because
    the mask tells it so. / /

    The /8 subnet (meaning there are 3 zeros in the mask), tells it there will
    be 16,777,210 hosts. If you try to put a router between them, it will not
    work because both are on the same subnet. Therefore, a superscope is

    Superscoping is to combine different subnets to "look" like one subnet. THat
    is the case if we are using a /24 mask (only 254 hosts) that are separated
    by routers. We can superscope the multiple /24's into one, put them on the
    same wire without the router, and they will act like one. You can do the
    same thing by reconfiguring all of your machines to be on the same subnet
    (common mask) and get rid of the superscoping. TO me, I would rather
    reconfigure than superscope.

    With ALL due respect, I believe a tutorial in subnetting may be helpful to
    fully understand what the masks mean and the requirements, advantages and
    disadvantages of superscoping will provide.

    Once again with ALL due respect, may I suggest a course? Its something that
    I teach (among other things), but that would be difficult thru email or
    posts. I haven't tried the ones below, but others told me they're ok and
    they seem ok to me too.



    Keep in mind, the subnet mask defines the subnet. That is the key to any IP
    addressing scheme and designing a multi-location infrastructure.

    Ace Fekay [MVP], Sep 5, 2006
  8. No it means,...don't use a Superscopes at all,....No Superscopes!
    Phillip Windell, Sep 5, 2006
  9. No Superscopes!!
    Phillip Windell, Sep 5, 2006
  10. ITCOM

    ITCOM Guest

    Thanks Information. I will sudty the subnet design.

    But what you proposal in our subnet design, my case as below:

    - Our Main network is 10.5.1.X (included server IP / WS IP)
    - PC grownth, IP not enought
    - Around 3 x Floor in same building connect this network using same IP range
    -IP assign not centrize

    - I want spit to 4 subnet, each subnet host in DHCP server.
    - The 10.5.1.x network subnet IP no change , only for server network.
    - Create 3 subnet for each floor.
    - Each subnet using Server network DHCP server manage.
    - I will setup a DHCP relay for each subnet connect to server network switch

    Please advice.
    -I want design each subnet for each floor
    -Each subnet IP arragne by server network server
    -Setup mutisubnet design.

    Please advice which the IP subnet design is better for me.

    ITCOM, Sep 7, 2006
  11. ITCOM

    Bill Grant Guest

    What subnet mask are you using at present? A 24-bit subnet mask will
    allow you to have about 250 machines on the segment.

    If you want to allocate a different subnet to each floor, that should
    cover your needs. You would give each floor its own subnet such as

    To make that clearer, one floor might use subnet mask . The machines in that subnet would get an IP address of
    10.5.2.x and a subnet mask of . Another floor might use and so on.

    For these machines to communicate you would need to have the segments
    connected by an IP router. If this router is capable of doing DHCP relay,
    you would only need one DHCP server with a scope for each subnet. When a
    client broadcasts on the network to find a DHCP server, the router will
    forward the request if there is no local DHCP server. The DHCP server will
    issue an IP address from the correct scope. It knows which subnet the
    machine is in, because it knows the IP address of the router which received
    the broadcast.
    Bill Grant, Sep 7, 2006
  12. In
    I agree with you Bill. An easy subnet design To add, he can also use one
    more bit in for a /23 to give 512 hosts.

    Ace Fekay [MVP], Sep 12, 2006
  13. ITCOM

    ITCOM Guest

    Right. Current using subnet only for 250 machine.
    ITCOM, Sep 12, 2006
  14. ITCOM

    ITCOM Guest

    Thanks Bill, Yes. current we using /24 bit subnet and only allow 250 host
    connect. So We design install Layer 3 cisco switch hub in compter room
    floor. Another each floor switch two truck connect to Computer room Layer 3
    switch, layer 3 each port must apply DHCP relay to computer room DHCP
    If you propose this case , that no need config supercope, just create normal
    scope in DHCP server ( eg, , just create normal scope in 10.5.1.x DHCP server), when subnet search DHCP
    server, the DHCP relay will forward broadcast to 10.5.1.x subnet DHCP

    ITCOM, Sep 12, 2006
  15. ITCOM

    ITCOM Guest

    Hi Ace, that our subnet mask will change to /23 , 10.5.1.x / .

    ITCOM, Sep 12, 2006
  16. ITCOM

    ITCOM Guest

    any help. my subnet knowloage very low level. please give me a suggest.

    ITCOM, Sep 13, 2006
  17. In
    You are welcome.
    Ace Fekay [MVP], Sep 15, 2006
  18. ITCOM

    ITCOM Guest

    Hi Ace
    How to setup the superscope in W2003, the superscope IP is , each
    scope in supercope is define /23 , /23 .....

    ITCOM, Sep 16, 2006
  19. ITCOM

    Bill Grant Guest

    No, you can't do that. If you change to a 23-bit subnet mask, you can't
    stay with the same networks as you had with a 24-bit subnet. With a 23-bit
    subnet mask, addresses starting with 10.5.2 and those starting with 10.5.3
    would be in the same IP subnet.

    Changing the subnet mask means that you can have twice as many IP
    addresses in each subnet. But it also means that you can only have half the
    number of subnets. One more bit is used for the host address and one less is
    used for the network address.

    The subnet contains the addresses through . The next useable subnet would be, containing the
    addresses through .
    Bill Grant, Sep 16, 2006
  20. In
    To add for ITCOM, just re-create your DHCP scopes to match what Bill
    explained. For instance you may have:

    Scope: - (/23)
    I left to for servers, printers, and anything else you
    need to set as static addresses.

    Then create one for the other subnet, such as:

    Scope: to (/23)


    Make sense?

    Ace Fekay [MVP], Sep 18, 2006
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