[squid-users] more bluecoat proxying

Henrik helped me with an issue we had with another proxy, a bluecoat
sg200, requesting documents from our reverse proxy squid. See thread
"bluecoat proxying to squid".

We now have another issue whereby the bluecoat will occasionally not cache
documents because it seems to think they have already expired, and the squid
gets every request that comes in as the bluecoat is constantly doing a
cache MISS.

Its an intermittent problem, sometimes the file will be cached
correctly on the bluecoat, sometimes not. At all times the file is
cached correctly on squid.

We have the "act-as-origin" feature enabled from latest squid cvs
sources, to update Date: and Expires: headers. I also removed the X-Origin-
Expires and X-Origin-Date headers in case they caused the issue.

e.g. request from bluecoat:

GET /Images/football/badges/13x13/b_7.png HTTP/1.1
If-None-Match: "12932d-367-46af1eb9"
Host: www.myhost.com
Cookie: CP=null*; Apache=192.168.50.144.166481185975779307
Accept: */*
Referer: http://www.myhost.com/blah/blah/0,,11660,00.html
Accept-Language: en-gb
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)
X-Forwarded-For: 10.160.21.76
Via: 1.0 NETCACHE01 (NetCache NetApp/5.5R6D25)
Cache-Control: max-stale=0
Connection: Keep-Alive
X-BlueCoat-Via: BD4F8D1E42E65ECB

and squid response:
HTTP/1.0 200 OK
Date: Tue, 07 Aug 2007 12:07:06 GMT
Expires: Tue, 07 Aug 2007 13:07:06 GMT
Server: Apache/1.3.37 (Unix)
Cache-Control: public, s-maxage=3600, max-age=3600
Last-Modified: Tue, 31 Jul 2007 11:36:25 GMT
ETag: "12790b-367-46af1eb9"
Accept-Ranges: bytes
Content-Length: 871
Content-Type: image/png
X-Cache: HIT from mysquid
Via: 1.0 mysquid:80 (squid/2.HEAD-CVS)
Connection: keep-alive

The bluecoat should be using the Expires: and Cache-Control: headers to
cache that image for 1 hour, and not make any more requests for it until
it expires, but the requests keep coming in.

Anybody seen this behaviour before ? Henrik perhaps you know of
some issue with squid again?

Thanks,

--
Michael