COMMAND EVERYTHING.
Creates a new Active Directory forest.
Microsoft ADDSDeployment reference: Creates a new Active Directory forest. The syntax and selected example below are adapted from the pinned Windows Server 2025 reference. Module availability, target configuration and delegated permissions determine whether it can run in your environment. Documentation and parameter text: Microsoft, CC BY 4.0; formatting adapted by Cmdlet World. No execution testing is claimed.
Use an account with the target resource permissions documented for Install-ADDSForest. Modifying administrative cmdlets may require elevation or delegated administration. This catalog does not assert that ordinary users can execute the command.
Windows / ADDSDeployment · Windows Server 2025 documentation; feature/module prerequisites apply
-Confirm- Prompts you for confirmation before running the cmdlet.
-CreateDnsDelegation- Indicates that this cmdlet creates a DNS delegation that references the new DNS server that you install along with the domain controller. Valid for Active Directory-integrated DNS only. The default is computed automatically based on the environment.
-DatabasePath- Specifies the fully qualified, non-Universal Naming Convention (UNC) path to a directory on a fixed disk of the local computer that contains the domain database, for instance, C:\Databases\NTDS. The default is %SYSTEMROOT%\NTDS.
-DnsDelegationCredential- Specifies the user name and password for creating DNS delegation. This parameter is skipped if the value for the CreateDnsDelegation parameter is either specified or computed to be $false.
-DomainMode- Specifies the domain functional level of the first domain in the creation of a new forest. Supported values for this parameter can be either a valid integer or a corresponding enumerated string value. For instance, to set the domain mode level to Windows Server 2008 R2, you can specify either a value of 4 or Win2008R2. The acceptable values for this parameter are: - Windows Server 2003: 2 or Win2003 - Windows Server 2008: 3 or Win2008 - Windows Server 2008 R2: 4 or Win2008R2 - Windows Server 2012: 5 or Win2012 - Windows Server 2012 R2: 6 or Win2012R2 - Windows Server 2016: 7 or WinThreshold The domain functional level cannot be lower than the forest functional level, but it can be higher. The default is automatically computed and set.
-DomainName (required)- Specifies the fully qualified domain name (FQDN) for the root domain in the forest.
-DomainNetbiosName- Specifies the NetBIOS name for the root domain in the new forest. For NetBIOS names to be valid for use with this parameter they must be single label names of 15 characters or less. If this parameter is set with a valid NetBIOS name value, then forest installation continues with the name specified. If this parameter is not set, then the default is automatically computed from the value of the DomainName parameter. For example, if this parameter is not specified and a single-label prefix domain name of 15 characters or less is specified within the value of the DomainName parameter, then promotion continues with an automatically generated NetBIOS domain name. For example, the prefix label corp within a full domain name value of corp.contoso.com would be a successful name choice. Note that if the name value given for this parameter is a name of 16 characters or more, then the forest installation fails.
-Force- Forces the command to run without asking for user confirmation.
-ForestMode- Specifies the forest functional level for the new forest. Supported values for this parameter can be either a valid integer or a corresponding enumerated string value. For example, to set the forest mode level to Windows Server 2008 R2, you can specify either a value of 4 or Win2008R2. The acceptable values for this parameter are: - Windows Server 2003: 2 or Win2003 - Windows Server 2008: 3 or Win2008 - Windows Server 2008 R2: 4 or Win2008R2 - Windows Server 2012: 5 or Win2012 - Windows Server 2012 R2: 6 or Win2012R2 - Windows Server 2016: 7 or WinThreshold The default forest functional level in Windows Server is typically the same as the version you are running. However, the default forest functional level in Windows Server 2008 R2 when you create a new forest is Windows Server 2003 or 2.
-InstallDns- Indicates that this cmdlet installs and configures the DNS Server service for the new forest. For forest installation, the default is $true.
-LogPath- Specifies the fully qualified, non-UNC path to a directory on a fixed disk of the local computer where the log file for this operation is written. For instance, C:\Logs. The default log file path if no other path is specified with this parameter is %SYSTEMROOT%\NTDS.
-NoDnsOnNetwork- Indicates that the DNS service is not available on the network. This parameter is used only when the IP setting of the network adapter for this computer is not configured with the name of a DNS server for name resolution. It indicates that a DNS server is installed on this computer for name resolution. Otherwise, the IP settings of the network adapter must first be configured with the address of a DNS server. Omitting this parameter indicates that the TCP/IP client settings of the network adapter on this server computer is used to contact a DNS server. Therefore, if you do not specify this parameter, ensure that TCP/IP client settings are first configured with a preferred DNS server address.
-NoRebootOnCompletion- Indicates that the cmdlet does not reboot the computer upon completion of this command. Omitting this parameter indicates the computer is rebooted upon completion of the command, regardless of success or failure. As a general rule, Microsoft support recommends that you do not use this parameter except for testing or troubleshooting purposes because once configuration has completed the server will not function correctly as either a member server or a DC until it is rebooted.
-SafeModeAdministratorPassword- Supplies the password for the administrator account when the computer is started in Safe Mode or a variant of Safe Mode, such as Directory Services Restore Mode. You must supply a password that meets the password complexity rules of the domain and the password cannot be blank. If specified with a value, the value must be a secure string. If this parameter is not specified, the cmdlet prompts you to enter and confirm a masked password. This is the preferred usage when running the cmdlet interactively. If additionally there are no other arguments specified with the cmdlet, you are prompted to enter a masked password for this parameter but no confirmation of the password entered is made. This is not recommended as it could allow a mistyped password to be configured. Another available advanced option is to use the ConvertTo-SecureString cmdlet and specify the password string inline as unmasked console input, which is also not a recommended security best practice in production deployments.
-SkipAutoConfigureDns- Indicates that the cmdlet skips automatic configuration of DNS client settings, forwarders, and root hints. This parameter is in effect only if the DNS Server service is already installed.
-SkipPreChecks- Indicates that the cmdlet performs only a base set of validations. This behavior is equivalent to the validations that were performed when using Dcpromo.exe in earlier versions of Windows Server to add a new forest. When this switch parameter is set, it specifies that additional preliminary checks should be bypassed. For more information on the scope of these additional preliminary checks that the ADDSDeployment module performs by default when using Windows Server 2012, refer to the table in the section ADPrep and Prerequisite Checking Architecture in AD DS Simplified Administration.
-SysvolPath- Specifies the fully qualified, non-UNC path to a directory on a fixed disk of the local computer where the Sysvol file is written. For example, C:\Logs\SYSVOL. The default path if no other path is specified with this parameter is %SYSTEMROOT%\SYSVOL.
-WhatIf- Shows what would happen if the cmdlet runs. The cmdlet is not run.
Windows with the ADDSDeployment module and the Windows feature or management tools that provide it. Confirm target connectivity and version compatibility using the linked Microsoft reference.
This cmdlet changes system state. Review every target and parameter in the official reference, test outside production, and prepare an appropriate backup or rollback. Do not execute the example automatically.