asp实现限制一个ip只能访问一次的方法

<% 
'///////////////////////////////////////////////////// 
'// // 
'//作用：一个IP地址只允许访问本页一次 // 
'//引用：<!-- #include file="Check_Ip.asp" --> // 
'// // 
'///////////////////////////////////////////////////// 

'Response.Charset = 936 '设置输出编码为简体中文 
'Response.Buffer = false '关闭缓冲区 

Dim Fso,ts,IpList,Cfs 

'设置Cookies函数 
Function SetCookie() 
Response.Cookies("IsBrow") = "Brow" 
Response.Cookies("IsBrow").Expires = Date+365 
End Function 

'记录IP地址函数 
Function WriteIp(FileName, IpAddress) 
Set Fso = Server.CreateObject("Scripting.FileSystemObject") 
Set ts = Fso.OpenTextFile(Server.MapPath(FileName),8,true) 
ts.WriteLine IpAddress 
ts.Close 
Set ts = Nothing 
Set Fso = Nothing 
End Function 

'读取IP地址函数 
Function ReadIpList(FileName) 
Set Fso = Server.CreateObject("Scripting.FileSystemObject") 
If Not Fso.FileExists(Server.MapPath(FileName)) Then 
CreateFile("Iplist.txt") 
Exit Function 
End If 

Set ts = Fso.OpenTextFile(Server.MapPath(FileName)) 
Iplist = ts.ReadAll 
ts.Close 
Set ts = Nothing 
Set Fso = Nothing 
ReadIpList = Iplist 
End Function 

'创建文件函数 
Function CreateFile(FileName) 
Set Fso = Server.CreateObject("Scripting.FileSystemObject") 
Set Cfs = Fso.CreateTextFile(Server.MapPath(FileName)) 
Cfs.Close 
Set Cfs = Nothing 
Set Fso = Nothing 
End Function 

'关闭当前IE窗口函数(注:IE6下通过,其他浏览器未测试) 
Function CloseWindow() 
'Response.Write "<script>window.location='javascript:window.opener=null;window.close();'</script>" 
Response.Redirect "http://www.baidu.com" 
End Function 

Ip = Request.ServerVariables("REMOTE_ADDR") '获取浏览者IP地址 

Cookie = Request.Cookies("IsBrow") '获取当前Cookies 
'Response.Write Cookie 

If Request.ServerVariables("HTTP_X_FORWARDED_FOR") <> "" Then 
Response.Write "本站不允许使用代理访问" 
Response.End() 
Else 
If Cookie = "Brow" Then 
CloseWindow() 
Else 
If Instr(ReadIpList("Iplist.txt"),Ip) <> 0 Then 
CloseWindow() 
Else 
WriteIp "Iplist.txt" , Ip 
End If 
SetCookie() 
End If 
End If 
%>