Announcement

Collapse
No announcement yet.

Dhcp bad address

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Dhcp bad address

    Hi,

    I have configured my DHCP server in a SBS 2008 box and all of a sudden all the leases occupied by BAD ADDRESS. Clients are not even getting the IP address from server and showing IP Address conflict. if I put a static IP which is out of my DHCP scope, to any of the system it will not accept the IP showing conflict.

    this became hectic now. I changed the IP address range from 192.168.1.0 to 192.168.2.0 but no luck and same problem.

    other devices connected to network are Linksys Wifi AP, HP Procurve switches, Printers, Site to Site Wireless equipment.

    Please help.

    Manoj Krishnan

  • #2
    Re: Dhcp bad address

    The scope should probably start with 192.168.1.1.

    Are you certain that no other devices are using any of the IP's contained within these subnets? Do you use routing and remote access? If so, where does it get its addresses from? What are the IP addresses of the server(s) and network devices - routers etc? Are they part of a different subnet?

    The command arp -a will give you a list of MAC addresses mapped to IP addreses. If any addresses that are in the DHCP scope appear in the output you will need to identify which devices use those addresses and determine if they are static. If they are static, you will need to adjust the scope so they are excluded.

    Sounds like you may need to do an inventory of your network devices.
    A recent poll suggests that 6 out of 7 dwarfs are not happy

    Comment


    • #3
      Re: Dhcp bad address

      Do you have a rogue DHCP server on the network
      e.g. DHCP on router/WAP
      ICS enabled on a desktop
      Tom Jones
      MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
      PhD, MSc, FIAP, MIITT
      IT Trainer / Consultant
      Ossian Ltd
      Scotland

      ** Remember to give credit where credit is due and leave reputation points where appropriate **

      Comment


      • #4
        Re: Dhcp bad address

        Hi, sounds to me like a rogue Dhcp server too. Do the event logs on the server shed any more light on the matter?
        If u stop the dhcp server service on the server, can a new client still get a dhcp address? If a. Client gets an address from some other device it will tell u the dhcp server ip address and u could track it from there.
        May also be worth a read:
        http://blogs.technet.com/b/teamdhcp/...ction.aspxogue

        Also check that DHCP conflict detection is set greater than 0 but less than 6
        http://technet.microsoft.com/en-us/l...=ws.10%29.aspx
        Last edited by uk_network; 10th October 2013, 22:03.
        Please remember to award reputation points if you have received good advice.
        I do tend to think 'outside the box' so others may not always share the same views.

        MCITP -W7,
        MCSA+Messaging, CCENT, ICND2 slowly getting around to.

        Comment


        • #5
          Re: Dhcp bad address

          Thanks for all your reply !

          I can't find any rough DHCP server on network. My DHCP server IP address is 192.168.1.3 and scope starts from 192.168.1.11 to 192.168.1.230. All the servers and network devices IP Addresses configured outside the scope only. The steps I have tried mentioned below.

          Step 1 :

          unplugged the DHCP server and tried connecting the client PC for any DHCP server - Not found any rough DHCP server in network

          Step 2 :

          Tried to put the IP manually in client PC - Not taking the IP saying CONFLICT

          Step 3 :

          Deleted all DHCP database files (c:\windows\system32\dhcp )and created the scope again. After that I turn OFF all switches and routers and started the DHCP service and started the switches - No luck .after some time DHCP lease page started showing BAD_ADDRESS

          Step 4 :

          Changed the entire IP address range to 192.168.2.0 updated in AD , DHCP etc, still I got the BAD ADDRESS error in DHCP lease

          Step 5 :

          Deleted all DHCP database files (c:\windows\system32\dhcp )and created the scope again. After that I turn OFF all switches and routers and started the DHCP service and started the switches one by one. somehow it is working fine for last 24 hours. Couldn't find out the root cause. Suspect my HP Procurve switches or any system with virus

          Attaching the DHCP log when this problem started. problem started at 3:PM. I suspect there was a database cleanup happened this time then this problen started.

          Thanks,
          Manoj Krishnan
          Attached Files
          Last edited by manukriz; 11th October 2013, 12:08.

          Comment


          • #6
            Re: Dhcp bad address

            Check that How DNS Scavenging and the DHCP Lease Duration Relate
            http://blogs.technet.com/b/askpfe/ar...on-relate.aspx

            check that allow dynamic updates is enabled http://technet.microsoft.com/en-us/l.../cc725703.aspx
            Please remember to award reputation points if you have received good advice.
            I do tend to think 'outside the box' so others may not always share the same views.

            MCITP -W7,
            MCSA+Messaging, CCENT, ICND2 slowly getting around to.

            Comment


            • #7
              Re: Dhcp bad address

              Hi,

              I have changed the DHCP Scope to 14 days and changed the scavenge aging to 6 days for both. I just wonder why MS kept it OFF by default. Lets see how this changes will help me. Just to remind my DNS server is an AD integrated one and the DHCP server is installed on this same SBS 2008 Box.

              What is the best conflict detection attempt value ?

              Cheers !
              Manoj Krishnan

              Comment


              • #8
                Re: Dhcp bad address

                Hi, our conflict detection has a value of 2. I hope this helps to resolve your issue.
                Please remember to award reputation points if you have received good advice.
                I do tend to think 'outside the box' so others may not always share the same views.

                MCITP -W7,
                MCSA+Messaging, CCENT, ICND2 slowly getting around to.

                Comment


                • #9
                  Re: Dhcp bad address

                  There's a little more on this with an explanation here:

                  http://technet.microsoft.com/en-us/l...(v=ws.10).aspx

                  Note that you need to select the server, then select the IPV4 node before opening the Properties dialog.
                  A recent poll suggests that 6 out of 7 dwarfs are not happy

                  Comment

                  Working...
                  X