.NET Simple browser with local DNS system

Code
Public Class Form1



    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

      wBro.GoBack()

    End Sub



    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click

      wBro.GoForward()

    End Sub



    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

      wBro.GoHome()

    End Sub



    Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click



      ' We should first check to see if the TLD in the url box is one of our private TLDs.



      Dim tld = getTLD() ' Grab the TLD using our custom function we programmed



      If tld = "pld" Then ' PLD is our Private Level Domain extension that we are going to use for this project



      ' It is our PLD, so have the browser grab the special private server information and have it open



      Dim url As String

      url = txtURL.Text.Replace("http://", "")

      url = url.Replace("https://", "")



      wBro.Navigate(getPLDServer(url))



      Else



      ' It isn't our PLD, so we will have the web browser load it normally.

      wBro.Navigate(txtURL.Text)



      End If



    End Sub



    Private Function getTLD()



      Dim url As String() = txtURL.Text.Split(".")

      Dim tld As String = url(url.Count - 1)



      Return tld



    End Function



    Private Function getPLDServer(ByVal pURL As String)



      Dim pServer As String = Nothing



      Dim rServer As New System.IO.StreamReader("dns.txt")



      Do Until rServer.EndOfStream



      Dim curLine As String = rServer.ReadLine



      If curLine.Split(":")(0).ToLower = pURL.ToLower Then



      pServer = curLine.Split(":")(1)



      End If



      Loop



      rServer.Close()



      If pServer = Nothing Then



      pServer = "file://" & Application.StartupPath & "/404.html" ' The PLD was not found in the database



      End If



      Return pServer



    End Function



End Class