Determine whether the client is on the Intranet or the internet! ASP

<%
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

Userip = ip2num (request. servervariables ("remote_addr "))


If (userip> ip2num ("192.168.0.0") and userip <ip2num ("192.168.255.255") or (userip> ip2num ("127.0.0.0") and userip <ip2num ("127.255.255.255 ")) or (userip> ip2num ("10.0.0.0") and userip <ip2num ("10.20.255") then
Response. Write "internal IP address"
End if
%>