Private Function CheckAuthenticationAD(ByVal loginName As Strig, ByVal password As String) As Boolean

        Dim authOk As Boolean = False

        Try
            Dim de = New DirectoryEntry("LDAP://myADServer/OU=myOU1,OU=myOU2,DC=myDC1,DC=myDC2", loginName, password)

            Dim Searcher As New System.DirectoryServices.DirectorySearcher(de)
            Searcher.SearchScope = DirectoryServices.SearchScope.OneLevel
            Try
                Dim Results As System.DirectoryServices.SearchResult = Searcher.FindOne
                authOk = Not (Results Is Nothing)
            Catch
            End Try
        Catch ex As Exception
            Throw
        End Try

        Return authOk
    End Function