CDN应用的ASP网站如何获取用户真实IP

function checkip(checkstring)'用正则判断IP是否合法
dim re1
set re1=new RegExp
re1.pattern="^[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}$"
re1.global=false
re1.Ignorecase=false
checkip=re1.test(checkstring)
set re1=nothing
end function

function get_cli_ip()'取真实IP函数，先 HTTP_CLIENT_IP 再 HTTP_X_FORWARDED_FOR 再 REMOTE_ADDR
dim client_ip
if checkip(Request.ServerVariables("HTTP_CLIENT_IP"))=true then
get_cli_ip = checkip(Request.ServerVariables("HTTP_CLIENT_IP"))
else
MyArray = split(Request.ServerVariables("HTTP_X_FORWARDED_FOR"),",")
if ubound(MyArray)>=0 then
client_ip = trim(MyArray(0))
if checkip(client_ip)=true then
get_cli_ip = client_ip
exit function
end if
end if
get_cli_ip = Request.ServerVariables("REMOTE_ADDR")
end if
end function