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A duplicate name exists on the network

    Question

  • Hi, I'm having this issue when computers are starting up 'A duplicate name exists on the network' I've been trolling through the threads here trying all the fixes but to no avail.

    I have a

    Server 2008 x64 domain with x2 DCs, (at 2008 operational level)

    Exchange 2007 x64,

    DNS servers on both DCs (one Primary one secondary)

    x1 DHCP server on main DC

    It is only happening to some of my Win XP boxes and two Win 2003 Server boxes I have (one is on a VMware ESX cluster), none of my 2008 servers nor my two Windows 7 laptops are affected.

    I don't have a WINS server; I am assuming it's a DNS issue*. I have scavanged stale records, tried to remove the boxes from the domain, delete them from OUs and rejoin with different names but immediately I get the same message. I've also removed all A records from DNS and even leases from DHCP and let them repopulate but that didn't work either.

    Now it seems to be affecting my back up server as it cannot start many of it's services I assume because it's in a offline mode.

     

    This is the reult of ipconfig /all from one affected server

    Windows IP Configuration

       Host Name . . . . . . . . . . . . : backupserver
       Primary Dns Suffix  . . . . . . . : sunrise.local
       Node Type . . . . . . . . . . . . : Unknown
       IP Routing Enabled. . . . . . . . : No
       WINS Proxy Enabled. . . . . . . . : No
       DNS Suffix Search List. . . . . . : sunrise.local

    Ethernet adapter Local Area Connection which is on a static IP address:

       Connection-specific DNS Suffix  . :
       Description . . . . . . . . . . . : HP NC320i PCIe Gigabit Server Adapter
       Physical Address. . . . . . . . . : 00-1A-4B-F1-46-0F
       DHCP Enabled. . . . . . . . . . . : No
       IP Address. . . . . . . . . . . . : 10.44.49.2
       Subnet Mask . . . . . . . . . . . : 255.255.255.0
       Default Gateway . . . . . . . . . : 10.44.49.4
       DNS Servers . . . . . . . . . . . : 10.44.49.6
                                           10.44.49.7

    If anyone can help it would be appreciated very much.

     

    * Since I wrote that I have rebuilt my DNS server from scratch but it's had no effect on the issue.



    BSc IT, MCSE
    Monday, July 04, 2011 5:28 AM

Answers

  • Another thought... Find the error reported in the event logs, then usually in there it will have the IP address of the offending machine listed in HEX in the details of the error near the end...

     

    Hope this helps, I managed to find a rogue network copier advertising itself with a duplicate workstation name this way...

    Monday, July 04, 2011 1:11 PM
  • Hi, Well you set me on the right track. I looked up in the event log and found an error 'NetBT'

    The name "SUNRISE        :0" could not be registered on the Interface with IP address 10.44.49.12. The machine with the IP address 10.44.49.153 did not allow the name to be claimed by this machine.

    For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

    So basically I'd named a Wi-Fi device with the same name as the domain. I never thought the name of the device (name, not SSID) would have any affect on the system. However it seems that because it was the same name, it was blocking any computer (WinXP/Winserver2003 only) from registering an IP address to the domain name Sunrise.

    All seems to be good with the world again! Thanks to everyone for your help. It was a really baffling scenario.


    BSc IT, MCSE
    • Marked as answer by isysman Monday, July 04, 2011 2:35 PM
    Monday, July 04, 2011 2:35 PM

All replies

  • Hello,

    that error message has nothing to do with DNS it is as it states, somewhere on the network a machine exist with the same name.

    Do you work with images to create new machines that are NOT prepared with sysprep?


    Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.
    Monday, July 04, 2011 6:22 AM
  • I wish it was that simple, it's definitely not a duplicate name, I have no duplicates on the network, and even if I change the name it still comes up with that message. I even went as far as removing one computer to a workgroup, deleting the record in AD, changing the name and re-adding it to the domain, but right away I get the same message.
    BSc IT, MCSE
    Monday, July 04, 2011 6:54 AM
  • Hello,

    do you have machines connected with multiple NICs to the same subnet?


    Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.
    Monday, July 04, 2011 7:13 AM
  • Windows - System Error. A Duplicate name exists on the network. Is not related to DNS issue.

    It indicate you that same computer name exists on the network. You should make sure all the NETBIOS names are different, Systems with the same SID which could lead this problem to overcome this problem use sysprep tool if the new system is created from old image.

     

    Thanks

    Monday, July 04, 2011 7:14 AM
  • Hi Guys, No multiple NICs on my machines, also not been using imaging software like Ghost etc. to make new computers...
    BSc IT, MCSE
    Monday, July 04, 2011 12:01 PM
  • If it's your backup server that is having the most difficulty connecting then it is most likely that which has the duplicate name somewhere.

    I would rename your backup server, reboot, then ping backupserver and see if you get a response.

    You could just switch it off for now and try the ping tests, maybe also have a look at the DHCP leases...

    Just a starting point for you...

    Monday, July 04, 2011 1:07 PM
  • Another thought... Find the error reported in the event logs, then usually in there it will have the IP address of the offending machine listed in HEX in the details of the error near the end...

     

    Hope this helps, I managed to find a rogue network copier advertising itself with a duplicate workstation name this way...

    Monday, July 04, 2011 1:11 PM
  • Hi, Well you set me on the right track. I looked up in the event log and found an error 'NetBT'

    The name "SUNRISE        :0" could not be registered on the Interface with IP address 10.44.49.12. The machine with the IP address 10.44.49.153 did not allow the name to be claimed by this machine.

    For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

    So basically I'd named a Wi-Fi device with the same name as the domain. I never thought the name of the device (name, not SSID) would have any affect on the system. However it seems that because it was the same name, it was blocking any computer (WinXP/Winserver2003 only) from registering an IP address to the domain name Sunrise.

    All seems to be good with the world again! Thanks to everyone for your help. It was a really baffling scenario.


    BSc IT, MCSE
    • Marked as answer by isysman Monday, July 04, 2011 2:35 PM
    Monday, July 04, 2011 2:35 PM
  • Hello,

    thanks for the feedback and to be honest that a duplicate name really exist. :-)


    Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.
    Monday, July 04, 2011 6:07 PM