Windows 2003 Server DHCP manual allocation

Posted on 2007-10-02
Last Modified: 2008-01-09
I am migrating from a Linux DHCP server to a Windows 2003 Server DHCP.

Our wireless network scope on the linux server requires that the MAC address be "authorized" (for a lack of better terms) in the dhcpd.conf file or it will not provide an IP address.

How do I accomplish this on DHCP using a Windows 2003 Server? MS states that It can be configured for manual allocation of IP addresses, but I must be missing something.
Question by:gelderjr
    LVL 13

    Expert Comment

    What you are talking about is what Microsoft refers to as a DHCP reservation.
    In your scope definition on the Windows 2003 DHCP Server, you'll see a section under the scope for Reservations. Right click, and you can add a new reservation. You'll provide a reservation name (we use the fully qualified domain name), the IP Address, the MAC address, and optionally, a description.

    Author Comment

    Correct - I will need to set reservations for each device using the MAC address.

    However, I do not want any IP addresses assigned without a reservation for the device.

    The easy solution would be to only include the IP addresses in teh scope of assigned equipment, as we are constantly removing equipment this would require that the scope be constantly changing and that equipment reservations would need to be changed to fill in the middle IP addresses.

    Can you set a 00:00:00:00:00:00 reservation for unused IP addresses that should not be assigned? That might provide a solution.

    Accepted Solution

    Correct, set reservations for known device MAC's.  

    Exclusion Ranges:
    Then, in the address pool, add an Exclusion Range that covers the remaining available address in the scope.  Or add a single IP range exclusion that will use up one IP Address at a time. This will effectively make no address available.  
    Be careful, if a reservation is in an exclusion range block, it will not be handed out.

    Then you won't have to modify your scope every time you want to add more addresses.  I use a combination of Exclusion Ranges and Single IP Exclusion Ranges to manage my 'free' IP Addresses.
    LVL 13

    Assisted Solution

    You can set a reservation with all zeros like you showed, but that (and kleptome's solution) will both present another problem.

    Microsoft DHCP calculates the number of available addresses in the pool for dynamic allocation. If your pool has 100 addresses in it, and you create 100 reservations for those addresses, then that leaves ZERO addresses available.

    DHCP will create error events every time the DHCP scope is checked. These events will indicate that you are out of available addresses. Since this is what you actually want, you'll just have to ignore those errors, and the red or yellow warning indicator in the DHCP Console.

    Author Comment

    OK - I agree that this will work around the problem, but I agree with dhoffman_98 as well that the error log will rapidly fill and if it is set to overwrite then we may miss other valuable information.

    Does MS DHCP have any other mechanisms to do this?

    In Linux I have the range (10.1.5.x) setup so that only MAC address assigned IP addresses are leased, all others available are not handed out when requested.

    Any other thoughts on this?

    Assisted Solution

    Yes, the log readability and availability of real errors can be an issue, but I use MS log parser to monitor my logs and have not really run into the issue of missing an error or not being able to monitor the real ones.  I have not seen a mechanism to perform a similar function as the one described for Linux.

    Expert Comment

    You can make use of MACfiltercallout.dll for this purpose ...wher you can authorise set of MAC address to be server by the DHCP server .

    Pls see

    for more details ...

    Let me know if you have any issues still .  Windows DHCP server works very great.

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