Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles Button1.Click
 
        Dim sIP As String = "78.46.67.51"
 
        Dim sBuffer As String = _
          My.Computer.FileSystem.ReadAllText( _
          "C:\WINDOWS\system32\drivers\etc\hosts")
 
        If sBuffer.Contains(sIP & " " & "l2authd.lineage2.com") Then
            MsgBox("Eintrag schon Vorhanden")
        Else
            My.Computer.FileSystem.CopyFile( _
    "C:\WINDOWS\system32\drivers\etc\hosts", _
    "C:\WINDOWS\system32\drivers\etc\hostsalt", _
    FileIO.UIOption.AllDialogs, _
    FileIO.UICancelOption.DoNothing)
 
            Dim file As System.IO.StreamWriter
            file = My.Computer.FileSystem.OpenTextFileWriter( _
              "C:\WINDOWS\system32\drivers\etc\hosts", True)
            file.WriteLine("78.46.67.51 l2authd.lineage2.com")
            file.WriteLine("78.46.67.51 nprotect.lineage2.com")
            file.Close()
 
            Process.Start("cmd.exe", "/C ipconfig/flushdns")
 
        End If

Public Shared Function PingHostOrIP(ByVal HostOrIP As String) As Boolean
  Try
    Return My.Computer.Network.Ping(HostOrIP)
  Catch
  End Try
End Function