NetBIOS domain of computer in PowerShell

Using the ADSystemInfo COM object should work, with no delay from Win32_NTDomain lookup:

$ADSystemInfo = New-Object -ComObject "ADSystemInfo"
$ADSystemInfo.GetType().InvokeMember("DomainShortName", "GetProperty", $null, $ADSystemInfo, $null)

There are other AD-related properties available from this COM object too:

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[EDITED - Originally included code for the WinNTSystemInfo COM object instead but a commenter pointed out this only returns the user's short domain - but ADSystemInfo does return the computer's short domain]

Here is another faster method than Win32_NTDomain, for getting the NetBIOS domain of the computer.

````powershell
# Get the computer system CIM/WMI
$computersystem = Get-CimInstance Win32_ComputerSystem

# Create a Windows Identity Principal object based on the name and domain in Win32_ComputerSystem
$ComputerPrincipal = [System.Security.Principal.WindowsIdentity]::new("$($computersystem.name)@$($computersystem.domain)")

# Split the NetBIOS name on \ and get the first value which should be the domain
($ComputerPrincipal.Name -split "\\")[0]


# Bonus point, the WindowsIdentity Principal has a bunch of other useful information.
# Like quick enumeration of the groups it's in (but needs to be translated from SID to NTAccount format).
$ComputerPrincipal.Groups.Translate([System.Security.Principal.NTAccount]).value
````