SBS DHCP Scope Full - Adding more licenses didn't help

Posted on 2006-04-04
Last Modified: 2008-02-01
Our business runs on SBS 2000, and for some time I have been aware that the SBS DHCP scope ( has been  full, with 245 total addresses and 245 in use, with 0 available.  I had assumed that this was because we have 15 clients connected and 15 licenses installed, and perhaps SBS was tying up the others.  These 15 clients were using all available address leases, and deleting one would open up a lease for another client to log on.  I recently purchased an additional 5 licenses to add more workstations, and discovered that we already had 20 licenses installed, and the additional 5 brought us to 25 licenses, but didn’t free up any more addresses in the SBS scope.  Of course, this means no other workstations can join the domain, even though we have 10 licenses installed and unused.  We are now urgently needing more than 15 clients at a time logged on.  Any ideas?
Question by:goodtimespowersports
    LVL 30

    Expert Comment

    You're maxxed out on the number of IP leases..... so therefore you need to create another subnet or other configuration of your network.
    LVL 30

    Expert Comment

    perhaps you can provdide detail on your network hardware configuration.

    Somewhere along the line you need a hardware solution.

    Accepted Solution

    I got on Google and found the answer here:

    It solved my problem.

    This is the text of the answer:
    "What you are experiencing (the leases being eaten up) is a known bug in the SBS DHCP server.  Me and one other fellow were trying to figure it out, and last I heard he was still waiting to hear back from MS on this (it's been a couple/few months now).  They had confirmed the bug and escalated it to the programmers, but I don't think we've heard back yet on a patch or hotfix.

    If you notice, the "Names" for the clients are the IP addresses that it's trying to assign instead of an actual computer name.  Another thing you may notice is that the "Unique ID" is crazy.  It's supposed to be the MAC address of the NIC on the other end but what it shows for those erroneous entries is actually the same IP string again shown as a hexadecimal representation of it's ASCII value.   i.e.:

    For IP Address the Client Name is also "" and the Unique ID is "3139322e3136382e31362..."

    Hex 31 = Decimal 49; ASCII 49 = "1"
    Hex 39 = Decimal 57; ASCII 57 = "9"
    Hex 32 = Decimal 50; ASCII 50 = "2"
    Hex 2E = Decimal 46; ASCII 46 = "."
    Hex 31 = Decimal 49; ASCII 49 = "1"
    Hex 36 = Decimal 54; ASCII 54 = "6"
    Hex 38 = Decimal 56; ASCII 56 = "8"

    A lot of the time it won't show all the erroneous entries in the DHCP
    manager.  You can 'fix' it by right-clicking the scope in the DHCP manager and pick "Reconcile", then hit "Verify" and it will make a list of all the ones it's not showing.

    Adjusting lease time doesn't seem to make any difference.

    After doing this they will show in the "Address Leases" list.  From there I just sort by Name to group all the IP "named" leases, then highlight and delete them manually.    It sucks and I find our server eats about 10 addresses a month or more.

    It's bizarre, but they know about it; my advice is to call MS and tell them that you have this problem and that you read here that it has been reported previously.  At the time MS said that they only had about 8-10 reports of it so far and it only seems to be SBS users."

    Author Comment

    In my case, I had to first reconcile the address leases in DHCP, then delete the 15 visible address leases, deactivate the scope in DHCP, and then reactivate the scope in DHCP, before all the bogus leases showed up.  I deleted all the bogus leases, and now have 245 total addresses, 10 in use, and 235 available.

    Whew!  How many hours of searching Microsoft's SBS website, the Experts-Exchange site, and Google I could have saved if this info had been readily available!  
    LVL 30

    Expert Comment

    no problem...I'm glad that you figured it out.

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