IP转换成数字，限制IP时用

'//IP转换成数字，限制IP时用
'@使用示例
'// userIPnum = IP2Num(Request.ServerVariables("REMOTE_ADDR"))
'// if userIPnum > IP2Num("192.168.0.0") and userIPnum < IP2Num("192.168.0.255") then
'// response.write ("<center>您的IP被禁止</center>")
'// response.end'
// end if

function IP2Num(sip)
dim str1,str2,str3,str4
dim num IP2Num=0
if isnumeric(left(sip,2)) then
str1=left(sip,instr(sip,".")-1)
sip=mid(sip,instr(sip,".")+1)
str2=left(sip,instr(sip,".")-1)
sip=mid(sip,instr(sip,".")+1)
str3=left(sip,instr(sip,".")-1)
str4=mid(sip,instr(sip,".")+1)
num=cint(str1)*256*256*256+cint(str2)*256*256+cint(str3)*256+cint(str4)-1
IP2Num = num
end if
end function