Orphaned DHCP server issue


Old DHCP servers still listed in Active Directory

You may have removed DHCP server service from Windows 2003 server but it may still be able to released IP address when you are not completely removed the server from LAN. Here is the scenario, having migrated Windows 2003 DC along with DHCP server from Windows 2003 to Windows 2008 Domain Controller. You may see duplicate IP address appearing and causing mischief and also noticed that when starting DHCP administrative tool from new DC server when selecting the authorized DHCP server; you can still see the old DHCP server listed here.

But no worries; you can still remove the orphaned DHCP server list using Netsh command. Following are the steps:

Show authorize DHCP server list:

C:\>Netsh DHCP show server

Unauthorize a DHCP Server from the List of Authorized Servers in AD:

Example:

C:\>netsh dhcp delete server dc1.yourdomain.local 192.168.1.1

Note:
dc1 here is the domain controller server which is also holding DHCP role/service.

A quick check again running to ensure orphan DHCP server has been removed.

C:\>Netsh DHCP show server

Often above steps may not able to remove the DHCP server list. To get around this you may use tool called ADSI Edit (please use this tool in extreme care).

  • Windows Start—>Run. Type: Adsiedit.msc then press Enter.
  • Open the configuration Container.
  • Expand Services.
  • Expand Net Services.


You can remove the orphaned DHCP server from here or user another methods as following.

double click on CH=DhcpRoot.

Scroll down until you find the dhcpServers attribute. Double click on that attribute and remove the offending servers from the value field. Apply and close)

See more details in the following link:

http://blogs.technet.com/b/networking/archive/2009/02/27/old-dhcp-servers-appear-in-the-list-of-authorized-servers-after-a-domain-rename.aspx

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About Robiul

Robiul has 15 years of continuous successful career experience in ICT with extensive background in System Engineering, IT infrastructure design, operations and service delivery, managing IT projects / MIS functions for local and multi-national companies with in-depth knowledge of multiple operating systems as well as construct / manage small to medium size Data Center. Proven ability to design and implement medium to semi-large scale LAN/WAN/WLAN and system infrastructures. Academic qualification: Master of Science in Information Systems. Professional certifications are: MCSE, CCNA, ITIL and FoundStone Security Professional, VCP, NetAPP, CISSP etc.
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