ASP prevents external submission methods

Simple method One
Server_v1=cstr (Request.ServerVariables ("Http_referer"))
Server_v2=cstr (Request.ServerVariables ("SERVER_NAME"))
If Mid (Server_v1,8,len (SERVER_V2)) <>server_v2 Then
Response.Write "<br><br><center><table border=1 cellpadding=20 bordercolor=black bgcolor=# Eeeeee width=450> "
Response.Write "<tr><td style= ' font:9pt Verdana ' >"
Response.Write "You submitted the wrong path, prohibit the submission of data from outside the site!" "
Response.Write "</td></tr></table></center>"
Response.End
End If

Method Two.
How to forge Http_referer.
So my function is undesirable.

Function Checkpagefrom ()
DIM Host,referer
HOST = Request.ServerVariables ("Http_host")
REFERER = Request.ServerVariables ("Http_referer")
If CStr (Left (Replace (REFERER, "http://", ""), Len (host)) = CStr (host) Then
Checkpagefrom = True
Else
Checkpagefrom = False

End If
End Function