Как получить имена компьютеров по их IP адресам?

Imports System.Net
Imports System.Net.Sockets
Imports System.DirectoryServices
Public Class Form1
    Dim a1, b, c, d As String
    Dim sw As New Stopwatch
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try
            sw.Start()
            ListBox1.Items.Clear()
            For i = 0 To 255
                a1 = "192.168.1."
                b = CStr(i)
                a1 = a1 & b
                Label1.Text = a1
                If My.Computer.Network.Ping(a1) Then
                    ListBox1.Items.Add(a1 & "   " & c)
                    c = ""
                    b = ""
                    a1 = ""
                End If
                ProgressBar1.Value = i
                b = ""
                a1 = ""
            Next
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        MsgBox("End" & vbNewLine & sw.Elapsed.ToString)
        sw.Reset()
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ProgressBar1.Maximum = 255
    End Sub

 MsgBox(System.Net.Dns.GetHostEntry("127.0.0.1").HostName)

Imports System.Net
Imports System.Net.Sockets
Imports System.DirectoryServices
Public Class Form1
    Dim a1, b, c, d As String
    Dim sw As New Stopwatch
    Dim address As String
    Dim n As Integer = 0
    Private Declare Function MessageBoxTimeOut Lib "user32" Alias "MessageBoxTimeoutA" (ByVal hWnd As Integer, ByVal lpText As String, ByVal lpCaption As String, _
                 ByVal uType As MsgBoxStyle, ByVal wLanguageId As Integer, ByVal dwMilliseconds As Integer) As Integer
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try
            sw.Start()
            ListBox1.Items.Clear()
            For i = 0 To 255
                a1 = "192.168.1."
                b = CStr(i)
                a1 = a1 & b
                If My.Computer.Network.Ping(a1) Then
                    n += 1
                    address = a1
                    Dim host As IPHostEntry = Dns.GetHostEntry(address.ToString)
                    c = host.HostName.ToString
                    ListBox1.Items.Add(a1 & vbTab & c)
                    MessageBoxTimeOut(Me.Handle, "Найдено-" & n, "Исчезнет через 3 сек.", MsgBoxStyle.Information, 0&, 3000)
                    c = ""
                    b = ""
                    a1 = ""
                End If
                ProgressBar1.Value = i
                b = ""
                a1 = ""
            Next
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        MsgBox("End" & vbNewLine & sw.Elapsed.ToString)
        sw.Reset()
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ProgressBar1.Maximum = 255
    End Sub
 End Class