利用asp获取客户端真实的IP地址

客户端IP有两种情况，一个是代理服务器上网的，另一种是直接上网的，所以要获取客户端IP也需要分开来获取。
<%
Function getIP()
Dim strIPAddr
If Request.ServerVariables("HTTP_X_FORWARDED_FOR") = "" OR InStr(Request.ServerVariables("HTTP_X_FORWARDED_FOR"), "unknown") >0 Then
 strIPAddr = Request.ServerVariables("REMOTE_ADDR")
ElseIf InStr(Request.ServerVariables("HTTP_X_FORWARDED_FOR"), ",") > 0 Then
strIPAddr = Mid(Request.ServerVariables("HTTP_X_FORWARDED_FOR"), 1, InStr(Request.ServerVariables("HTTP_X_FORWARDED_FOR"), ",")-1)
ElseIf InStr(Request.ServerVariables("HTTP_X_FORWARDED_FOR"), ";") > 0 Then
strIPAddr = Mid(Request.ServerVariables("HTTP_X_FORWARDED_FOR"), 1, InStr(Request.ServerVariables("HTTP_X_FORWARDED_FOR"), ";")-1)
Else
 strIPAddr = Request.ServerVariables("HTTP_X_FORWARDED_FOR")
End If
getIP = Trim(Mid(strIPAddr, 1, 30))
End Function
%>