DHCP - Addresses marked as used but they are not being used

Discussion in 'Server Networking' started by FNBTech, Sep 14, 2006.

  1. FNBTech

    FNBTech Guest

    My dhcp on a windows server 2000 box with spk 4 statest that I have 228
    addresses available, but it says I am using 218 with 10 left but I only have
    a total of 181 in leases, reservations, and exceptions. I have addresses out
    there that are available because if you ping them they come up timed out.
    They do not show as being used in leases, reservations or I have not put them
    as an exception. I have looked in Knowledge Issues but I cannot find any
    reason why this would be happening. I am adding 8 new computers so I will be
    down to 2 and it will be hard to function with just 2 unless I can get this
    issue figured out and use the other 45 that i should have available.

    FNBTech, Sep 14, 2006
    1. Advertisements

  2. Hi,

    ping is often not the best way to determine if IP address is in used or not.
    E.g. if user have enabled personal firewall -- you might not get ICMP (ping)
    reply, but the computer actually does have that IP address in use.
    What I usually do is also look at MAC address cache. If e.g. I don't get
    ping reply I will run

    arp -a

    and see if the computer's IP address and MAC address will show up in the
    cache. If it does and MAC address is valid then the computer on the network
    have that IP address in use.
    Miha Pihler [MVP], Sep 17, 2006
    1. Advertisements

  3. FNBTech

    FNBTech Guest

    Yes, I am aware of all of that. All the addresses that get a reply back when
    pinged add up to all the computer on my network. It is reading the ones that
    state timed out when pinged to the total value also. I have 181 computers on
    my network. I have 225 available addresses but dhcp says I am using 225 when
    I only have a total of 181 in reservation and leases. All other ones are not
    being used at all.
    I do not have windows firewall activated on winxpspk2 machines. My question
    is why would dhcp record all my addresses as being used when 1/4 of them are
    not being used at all.
    FNBTech, Sep 18, 2006
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.