Web Forms :: Restrict Users Based On IP Address On LAN Network In Website

in my asp.net+vb web page  which is use din INTRANET web . In a page i want to restrict the browsing for four peoples only, so that i used a code like below.

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim ipaddress As String
ipaddress = Request.ServerVariables("HTTP_X_FORWARDED_FOR")
If ipaddress = "" OrElse ipaddress Is Nothing Then
ipaddress = Request.ServerVariables("REMOTE_ADDR")
End If
iptxt.Text = (ipaddress)
If iptxt.Text = ("192.168.0.3") Then
Response.Redirect("err.aspx")
End If
end sub

in my asp.net+vb web page  which is use din INTRANET web . In a page i want to restrict the browsing for four peoples only, so that i used a code like below.

ProtectedSubPage_Load(ByVal sender AsObject,ByVal e AsSystem.EventArgs)HandlesMe.LoadDim ipaddress AsString ipaddress =Request.ServerVariables("HTTP_X_FORWARDED_FOR")If ipaddress =""OrElse ipaddress IsNothingThen ipaddress =Request.ServerVariables("REMOTE_ADDR")EndIf iptxt.Text=(ipaddress) If iptxt.Text=("192.168.0.3")ThenResponse.Redirect("err.aspx")EndIf