PeterMatthews used Ask the Experts™
I have win2003 Server sp2 with single dhcp scope.
i have a single sunbet, all servers & printers and some clients have static ip.
Lease duration is 3 days and conflict detection attempts is set to 2.
i can see on dhcp statistics we have 25% of available ip address and just of a sudden i get call from client that their machine can't access the network, on checking the dhcp statstics again i can see it's displaying 0%, i have seen this symptoms througout the day and not just when users logging in the mornings. Doing further checks on address leases i can see many entry with "Bad_Address", i've deleted all these but seems popping up again. I dont believe we're hitting our scope limit.
Just to mention- the dhcp server is installed on the active direcory/dns server.

please let me know if theirs any solution for this problem  

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bbaoIT Consultant

what do the Event Logs on System and DHCP say?
Firstly, can you confirm you only have 1 DHCP server or that none of your DHCP servers have overlapping scopes (i.e. giving out the same addresses). Also make sure your static addresses aren't in your DHCP scope or are static reserved within the scope.

Secondly, I would check the network settings on some of the machines coming up with BAD_ADDRESS. Do an ipconfig /all on a few of them and see if they have DHCP assigned addresses that are already in use. If so then maybe your scope is too small or your lease duration too long for the number of clients.


event id, 1063,1020.
we only have 1 dhcp server. my static ip address are within the scope. how do i exclude them from my scope?
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You can do either of the following

Add them as static reservations manually, you will need a list of the static IPs, hostnames and the MAC addresses of the computers you wish to add reservations for.
Open DHCP management and go to Scope -> Reservations and then right click and choose 'New Reservation'.

Reservation name is the hostname
IP address is the one you want to statically assign
MAC address is the MAC of the NIC that will be making the DHCP request
Description is to help you identify them later, such as Joe Bloggs or Marketing PC.

After this is done you can either leave the PCs set up with static assignments and alter the DHCP reservations yourself, or you can set those machines to DHCP and they will always receive the static IP you have given them.

Alternatively set all of the machines to DHCP and from DHCP management you would go to Scope -> Address Leases and right-click on the entry you would like to make a static reservation and choose 'Add to reservation'. This would most likely mean that your static IP machines end up with different IPs initially until you change their DHCP lease to a static reservation.

Best and simplest way to exclude the static addresses from the scope:
Assign a range for the static addresses like to
Assign a different range for the dynamic / DHCP addresses like to

Shorten the lease time to 4 hours.  It won't hurt and it will get rid of leases that are no longer used.  That may well open up available addresses.  Turning computers off and on and/or connecting and disconnecting them from the network can cause conflicts.  Trying to set a static address can totally fail if there's another device with the same address opertating.  So, if a device with a static address is turned off and, of course, it does not have a lease, then the DHCP server may assign the same address unless the ranges are as above.  Then, when the fixed IP device may fail to connect.

BAD ADDRESS can be caused by IP address conflict. Or by some problem with a particular NIC which sends a corrupted MAC address.

I would at first check that there is no "rogue DHCP server" on the network. It could be a DSL/cable router, a client with internet connection sharing enabled, a linux host with dhcp server installed

You can check these links:


I am recieving BAD ADDRESS for number of computers.
When i scanned my subnet i can see number of free ip addressess are available and they're not been reserved or excluded from dhcp server but i'm always  recieving error with all ip's has been used and cannot coneect any more machine to networks, by deleting bad address seems solves my problem.
bbaoIT Consultant
1. double check if you have more than ONE DHCP servers working on the same subnet. better use a sniffing tool such as MS Network Monitor to listen over the network.

2. double check if all DHCP clients are having the same Lease Expires date and time. if not, check if they received the IP from the same DHCP...


we have extended our scope and this problem seems to be solved now
Good news. Glad to have helped and that your problem has been resolved.

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