When you are promoting a new Domain Controller in to an existing Active Directory Forest/Domain, you let the default setting of “Any domain controller” to sync from and you are stuck at promotion process with this error message:
Error determining whether the target environment require adprep: Validation error Validation error: Unable to make an LDAP connection to server RandomDC01.company.com Exception: The specified server cannot perform the requested operation Details: Test.VerifyForestUpgradeStatus.ADPrep.Win32Exception.-2147467259
If I choose a closest domain controller manually, you still the ‘freaking’ error message:
Error determining whether the target environment require adprep: Validation error Validation error: Unable to check forest upgrade status for server ClosestDC1.company.com Exception: The specified server cannot perform the requested operation Details: Test.VerifyForestUpgradeStatus.ADPrep.Win32Exception.-2147467259
OK, now. What seems to be the ‘problem’? I believe the new server being promoted to a DC is NOT seeing the network or any domain controllers correctly. Check these few possible issues/solutions:
- Is the new server pings any other domain controllers? Can you Telnet port 389? Fix the Network card (IP, subnet or bad driver)
- Is any Firewall between the new server to existing domain controllers? Check here what firewall ports needs to open – https://support.microsoft.com/en-us/help/179442/how-to-configure-a-firewall-for-domains-and-trusts
- Is this new server a VM? check it is connected to correct (software) swtich/VLAN.
Anand, the Architect 