[squid-users] Question about Date header

 I have a question about the "Date" in response header.
As I know, the "Date" should be the just time when the server response
the request. But If I request through squid2.6 as a cache server, I get
the right "Date" only the first time! Squid return the same
"Date"/"Expires"...after the second request.
I guess that squid might return the headers exist in the cache file. I
strings one file and see text as follows:
http://tech.china.com/zh_cn/mobile/market/11025044/20080102/images/2008010209212895055100.jpg
HTTP/1.1 200 OK
Server: nginx/0.7.62
Date: Fri, 03 Sep 2010 12:40:54 GMT
Content-Type: image/jpeg
Content-Length: 47072
Last-Modified: Wed, 02 Jan 2008 01:15:06 GMT
Connection: keep-alive
Expires: Fri, 03 Sep 2010 13:10:54 GMT
Cache-Control: max-age=1800
Accept-Ranges: bytes

But when I test a url through a CDN's cache, I see the "Date" changes
every test.
wget -S http://images7.moonbasa.com/ProductImg/Middle/WX10010090M01.jpg
-O /dev/null
--22:00:09-- http://images7.moonbasa.com/ProductImg/Middle/WX10010090M01.jpg
Resolving images7.moonbasa.com... 123.183.210.173
Connecting to images7.moonbasa.com|123.183.210.173|:80... connected.
HTTP request sent, awaiting response...
HTTP/1.1 200 OK
Server: DnionOS/1.0
Date: Fri, 03 Sep 2010 14:00:22 GMT
Content-Type: image/jpeg
Connection: keep-alive
Cache-Control: max-age=31104000
Content-Length: 13726
Last-Modified: Mon, 23 Aug 2010 09:06:04 GMT
Accept-Ranges: bytes
ETag: "2074f569a242cb1:1b20"
Vary: Accept-Encoding
X-Powered-By: ASP.NET
X-Cache: MISS from CT-SHBA-177-211.fastcdn.com
Age: 12119
X-Cache: HIT from CT-QHD-210-146.fastcdn.com
Length: 13726 (13K) [image/jpeg]
Is there anything wrong?
Received on Fri Sep 03 2010 - 14:00:43 MDT