40
Hit-metering for ads (3)
GET /i/foo/bar.gif HTTP/1.1
Host: static.example.net
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7) Gecko/20040707 Firefox/0.8
Referer: http://www.example.com/foo/bar.php?abc=123&def=456

HTTP/1.1 200 OK
Date: Wed, 28 Jul 2004 23:45:07 GMT
Last-Modified: Mon, 05 Oct 1998 18:32:51 GMT
ETag: "69079e-ad91-40212cc8"
Cache-Control: public,max-age=315360000
Expires: Mon, 28 Jul 2014 23:45:07 GMT
Content-Length: 6096
Content-Type: image/gif

GIF89a...