To use the ServerVariables property of the request object, use it to get the value of the environment variable. The syntax used is: Request.ServerVariables(variable), "variable" represents the name of the environment variable, such as the server host name, the web server software name, etc. If "variable" is "REMOTE_ADDR", it represents the visitor's IP address, and through it, the filtering of the IP address can be achieved.
The source program is as follows: (File name: demo.ASP)
<html>
<head>
<metahttp-equiv="Content-Type"content="text/html;charset=gb_2312-80">
<metaname="GENERATOR" content="MicrosoftFrontPageExpress2.0">
<style>
<!---
.as{line-height:15px;font-size:9pt}
a:hover{color:rgb(0,51,240);text-decoration:underline}
.p9{font-family:"宋体";font-size:9pt;line-height:15pt}
.p12{font-family: "宋体";font-size:12pt;line-height:18pt}
a:link{text-decoration:none;}
a: visited{text-decoration:none;}
a:hover{text-decoration:underline;font-size:125%;color:blue}
－>
</style>
<title>ASP page firewall function demonstration</title>
</head>
<bodybackground="back.jpg">
<%
′ Use Request.ServerVariables("REMOTE_ADDR") to get the IP address and save it in the variable rip
rip=Request.ServerVariables("REMOTE_ADDR")
strip=cstr(rip)
′ Get the value of the third segment of the IP address and save it to strip
fori=1to2
strip=right(strip,len(strip)-instr(1,strip,"."))
next
strip=left(str,instr(1,str,".")-1)
′IP address validity verification and password verification, including two aspects:
'If the IP address is in compliance, pass verification; if the IP address does not conform, check whether the entered password is correct (the password here is "asp")
if(left(rip,5)<>"127.1" orstrip<"1" orstrip>"50")andrequest("Passwd")<>"asp"then
%>
<p><fontcolor="#FF0000">Sorry, your IP is <%=rip%>, and the IPs that can be accessed on this page are between 127.1.1.* and 127.1.50.*. If you are a user of the internal network of this unit, please make sure that your browser does not use a proxy!<BR></font></p>