Questions in the web poll

Forged a vote recently, but there's a problem.

get/bb/view.asp?id=199 http/1.1
Accept: */*
referer:http://www.gzxxw.com/bb/index.asp?page=2
Accept-language:zh-cn
Ua-cpu:x86
Accept-encoding:gzip, deflate
user-agent:mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Avant Browser;. NET CLR 2.0.50727)
Proxy-connection:keep-alive
Host:www.gzxxw.com
Pragma:no-cache
Cookie:ipaddress=210%2e168%2e44%2e25; ASPSESSIONIDSACRRACC=ECKFLJEBOLANHBGFLNBFGJFF; Aspsessionidscdtscac=opmfmhfboofoibobldekdifn
The second HTTP request is the same station:
get/bb/view.asp?id=199 http/1.1
Accept: */*
referer:http://www.gzxxw.com/bb/index.asp?page=2
Accept-language:zh-cn
Ua-cpu:x86
Accept-encoding:gzip, deflate
user-agent:mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Avant Browser;. NET CLR 2.0.50727)
Proxy-connection:keep-alive
Host:www.gzxxw.com
Pragma:no-cache
Cookie:ipaddress=210%2e168%2e44%2e25; ASPSESSIONIDSACRRACC=ECKFLJEBOLANHBGFLNBFGJFF;

Web site http://www.gzxxw.com/bb/View.asp?ID=199
I could have used a fake ticket to change the value of the cookie IPAddress variable, but now I'm going to ask the teacher, Here's my analysis:
The second HTTP request is one less than the previous one. A cookie variable may be that I don't have empty browser cookie information, and now there are only two cookie   ASPSESSIONIDSACRRACC should be the SessionID of IIS. I don't know if this can be used in IIS to verify the uniqueness of the customer (I don't think so). I searched on the internet did not have too much this aspect of things, in order to efficiency directly to the teacher's mailbox to send a hehe, that is, verification may be an IP authentication, I do not know how the server side is implemented, I think now is probably the first to get the customer sent to the cookie in the IPAddress variable in the system variable in the ASP to obtain the request of the client's IP, I now want server-side validation is one of these judgments: 
if (client-side judgment request ip= Cookie in the IPAddress)
{Someone's vote is added to a}
kind of. Of course, I want to make a logical loophole now, I don't know if I can do it.   I want to forge a cookie variable
ipaddress= "Previous IP" + Space + "or 1=1 "  But now do not know how to encode:
equal to the server-side validation has become a forever of the  
, but now do not know if the IIS server will be closed to the screen