hi i have a server that installed windows 2008 server on it and it provide AD service and DNS service too. i have an additional for this server that is the AD additional and the secondry DNS of the primary. now i want to change the OS of the primary to windows 2008 R2 without changing plat form of the network and don't join again the stations. please help us how must do it?

Hello, first of all there is no primary/secondary DC. All DCs are RW except RODCs. If your 2008 servver 32 bit? If yes, you have to: Transfer FSMO roles to the other DC Demote the DC using dcpromo perform a clean install of the 2008 R2 OS Promote again the DC using dcpromo Before proceeding, make sure that the other DC is a GC. If your 2008 server is 64 bit, then try to perform an inplace upgrade; This posting is provided "AS IS" with no warranties or guarantees , and confers no rights. Microsoft Student Partner Microsoft Certified Professional Microsoft Certified Systems Administrator: Security Microsoft Certified Systems Engineer: Security Microsoft Certified Technology Specialist: Windows Server 2008 Active Directory, Configuration Microsoft Certified Technology Specialist: Windows Server 2008 Network Infrastructure, Configuration Microsoft Certified Technology Specialist: Windows Server 2008 Applications Infrastructure, Configuration

Hello, if the hardware is capable of the new OS you can insert the installation disk and run an inplace upgrade, if the Windows server 2008 is a 64bit version. Just follow the wizard. If the Windows server 2008 is NOT 64bit you have to do a reinstall of the server. This requires the transfer of FSMO roles to the other DC and also you have to make the other DC Global catalog server and DNS server. Additional all domain machines must be configured to use the new DNS as preferred on the NIC now. If the above mentioned steps are done you have run dcpromo to demote this machine to member server and then remove it from AD UC and AD sites and services and cleanup DNS zones and zone properties from the old entries. Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.