Get DFS Server name and local path from UNC path

2015-10-27

Question

_{Tuesday, October 27, 2015 7:36 AM}

I'm working on Windows Server 2012 which comes by default with various DFS CmdLets.

What I'm trying to do is get the ComputerName and the local path of a specific UNC share, that is hosted by other DFS servers (Win Srv 2008 R2) on the domain by using PowerShell.

An example:

Get-DfsnFolderTarget -Path '\\domain.net\share\folder\'

Expected result:

ComputerName = 'Server1'
Path         = 'E\Home\folder'

I'm not really a network engineer, but I can't seem to find a way to retrieve this information based on the UNC path. Every time I try the CmdLet above I get an error:

Get-DfsnFolderTarget : Cannot get DFS folder properites on "\\domain.net\share\folder\"
At line:1 char:1
+ Get-DfsnFolderTarget -Path '\\domain.net\share\folder\'
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (MSFT_DfsNamespaceFolderTarget:ROOT\Microsoft\...aceFolderTarget) [Ge 
   t-DfsnFolderTarget], CimException
    + FullyQualifiedErrorId : Windows System Error 1168,Get-DfsnFolderTarget

Get-DfsnFolderTarget : The requested object could not be found.
At line:1 char:1
+ Get-DfsnFolderTarget -Path '\\domain.net\share\folder\'
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (MSFT_DfsNamespaceFolderTarget:ROOT\Microsoft\...aceFolderTarget) [Ge 
   t-DfsnFolderTarget], CimException
    + FullyQualifiedErrorId : MI RESULT 6,Get-DfsnFolderTarget

When trying a Test-Path \\domain.net\share\folder\ it does say that it can be found. So I don't really understand.

All replies (2)

_{Tuesday, October 27, 2015 9:38 AM ✅Answered}

After Googling around for hours I found the solution to my own problem. It's not really native PowerShell, but it does the job. For anyone else interested, here is the code:

Function Get-DFSDetails {
<# 
    .SYNOPSIS   
        Gets DFS details for a UNC path.

    .DESCRIPTION
        The Get-DFSDetails CmdLet gets DFS details like DFS Server name, DFS Share name and the local path on the DFS Server for a specific UNC path.

    .PARAMETER Credentials 
        PowerShell credential object used to connect to the DNS Server to retrieve the local path on the server.

    .PARAMETER Path 
        Specifies a UNC path for the folder.

    .EXAMPLE
        Get-DFSDetails -Path '\\domain.net\HOME\Bob' -Credentials $Credentials
        Gets the DFS details for the UNC path '\\domain.net\HOME\Bob'

        Path         : \\domain.net\HOME\Bob
        ComputerName : SERVER1.DOMAIN.NET
        ComputerPath : E:\HOME\Bob
        ShareName    : HOME

    .EXAMPLE
        '\\domain.net\HOME\Mike', '\\domain.net\HOME\Jake' | Get-DFSDetails -Credentials $Credentials
        Gets the DFS details for the UNC paths '\\domain.net\HOME\Mike' and '\\domain.net\HOME\Jake'

        Path         : \\domain.net\HOME\Mike
        ComputerName : SERVER1.DOMAIN.NET
        ComputerPath : E:\HOME\Mike
        ShareName    : HOME 

        Path         : \\domain.net\HOME\Jake
        ComputerName : SERVER2.DOMAIN.NET
        ComputerPath : E:\HOME\Jake
        ShareName    : HOME    

    .NOTES
        CHANGELOG
        2015/10/27 Function born #>

    [CmdLetBinding()]
    Param (
        [Parameter(Mandatory, Position=0)]
        [PSCredential]$Credentials,
        [Parameter(Mandatory, ValueFromPipeline, Position=1)]
        [ValidateScript({
            if (Test-Path -LiteralPath $_ -PathType Container) {$true}
            else {throw "Could not find path '$_'"}
        })]
        [String[]]$Path
    )

    Begin {
$signature = @'
using System;
using System.Collections.Generic;
using System.Management.Automation;
using System.Runtime.InteropServices;

public class Win32Api
{
    [DllImport("netapi32.dll", SetLastError = true)]
    private static extern int NetApiBufferFree(IntPtr buffer);

    [DllImport("Netapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
    private static extern int NetDfsGetClientInfo
    (
    [MarshalAs(UnmanagedType.LPWStr)] string EntryPath,
    [MarshalAs(UnmanagedType.LPWStr)] string ServerName,
    [MarshalAs(UnmanagedType.LPWStr)] string ShareName,
    int Level,
    ref IntPtr Buffer
    );

    public struct DFS_INFO_3
    {
        [MarshalAs(UnmanagedType.LPWStr)]
        public string EntryPath;
        [MarshalAs(UnmanagedType.LPWStr)]
        public string Comment;
        public UInt32 State;
        public UInt32 NumberOfStorages;
        public IntPtr Storages;
    }
    public struct DFS_STORAGE_INFO
    {
        public Int32 State;
        [MarshalAs(UnmanagedType.LPWStr)]
        public string ServerName;
        [MarshalAs(UnmanagedType.LPWStr)]
        public string ShareName;
    }

    public static List<PSObject> NetDfsGetClientInfo(string DfsPath)
    {
        IntPtr buffer = new IntPtr();
        List<PSObject> returnList = new List<PSObject>();

        try
        {
            int result = NetDfsGetClientInfo(DfsPath, null, null, 3, ref buffer);

            if (result != 0)
            {
                throw (new SystemException("Error getting DFS information"));
            }
            else
            {
                DFS_INFO_3 dfsInfo = (DFS_INFO_3)Marshal.PtrToStructure(buffer, typeof(DFS_INFO_3));

                for (int i = 0; i < dfsInfo.NumberOfStorages; i++)
                {
                    IntPtr storage = new IntPtr(dfsInfo.Storages.ToInt64() + i * Marshal.SizeOf(typeof(DFS_STORAGE_INFO)));

                    DFS_STORAGE_INFO storageInfo = (DFS_STORAGE_INFO)Marshal.PtrToStructure(storage, typeof(DFS_STORAGE_INFO));

                    PSObject psObject = new PSObject();

                    psObject.Properties.Add(new PSNoteProperty("State", storageInfo.State));
                    psObject.Properties.Add(new PSNoteProperty("ServerName", storageInfo.ServerName));
                    psObject.Properties.Add(new PSNoteProperty("ShareName", storageInfo.ShareName));

                    returnList.Add(psObject);
                }
            }
        }
        catch (Exception e)
        {
            throw(e);
        }
        finally
        {
            NetApiBufferFree(buffer);
        }
        return returnList;
    }
}
'@

        if (-not ('Win32Api' -as [Type])) {
            Add-Type -TypeDefinition $signature
        }
    }

    Process {
        foreach ($P in $Path) {
            Try {
                # State 6 notes that the DFS path is online and active
                $DFS = [Win32Api]::NetDfsGetClientInfo($P) | Where-Object { $_.State -eq 6 } | 
                    Select-Object ServerName, ShareName

                $SessionParams = @{
                    Credential    = $Credentials
                    ComputerName  = $DFS.ServerName
                    SessionOption = New-CimSessionOption -Protocol Dcom
                }
                $CimParams = @{
                    CimSession = New-CimSession @SessionParams
                    ClassName  = 'Win32_Share'
                }
                $LocalPath = Get-CimInstance @CimParams | Where-Object Name -EQ $DFS.ShareName | 
                    Select-Object -ExpandProperty Path

                [PSCustomObject][Ordered]@{
                    Path         = $P
                    ComputerName = $DFS.ServerName
                    ComputerPath = $LocalPath + ($P -split $DFS.ShareName, 2)[1]
                    ShareName    = $DFS.ShareName
                }
            }
            Catch {
                Write-Error $Error[0].Exception.Message
                $Global:Error.Remove($Global:Error[0])
            }
        }
    }
}

_{Wednesday, October 28, 2015 8:36 AM}

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Get DFS Server name and local path from UNC path

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