In my portal environment, I have enabled the non-share cache for my theme, page and portlet as following:




The page and portlet are authorized to anonymous, so the user can view the page (with POST method) and portlet without login. I inspected the response hander and found the cache was enabled:

================================================== ==========================
Proxy-Connection: Keep-Alive
Via: HTTP/1.1 chap01s (IBM-PROXY-WTE)
Date: Thu, 25 Jan 2007 04:54:40 GMT
Server: IBM_HTTP_SERVER/ Apache/1.3.28 (Unix)
Set-Cookie: JSESSIONID=0000unOraydouzoP1IHXfzVBAoJ:-1;Path=/
Cache-Control: private
Cache-Control: max-age=36000
Expires: Thu, 25 Jan 2007 14:54:40 GMT
Vary: User-Agent
Keep-Alive: timeout=120, max=100
Content-Type: text/html; charset=Big5
Warning: 214 chap01s "Transmogrified" "Thu, 25 Jan 2007 04:54:40 GMT"
CL: 45242
Transfer-Encoding: chunked
================================================== ==========================

However, when the user login my portal, and access the same page, the cache was disabled. We can tell from the following response header:

================================================== ==========================
Accept-Language: zh-tw,en-us;q=0.5
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)
Content-Type: application/x-www-form-urlencoded
Content-Length: 128
Connection: Keep-Alive
Cache-Control: no-cache
Cookie: JSESSIONID=0000unOraydouzoP1IHXfzVBAoJ:-1; LtpaToken=0bo4F++qlW5ng5wC0wV6u2Z91/P6JqEj9iLQoQ/v6lo4EgVk6uIP4uDeae14Ug8zARSHpceIPKIW1DFlpsVy/HzKbI6SN1Zd0K2TeB5Ji7T9MiV6VumPJgecd2aBs4gH2woi9oU PszwP458y8xOEYp/Ir4DJyztUzlrdOwID0zMLi0i5BHANu2vkLQx21WkycqR59J4Jt/mpbpGV4raHMH1tw+UvwbfRZYNjL2xXEZ8s6Y06LSK7BDSaWA39 p6vHq9Rk2O6rervCgsSxY2JEB18iPcD07MYszyjHPrbW68I3sN UAUqcXSXoZEA3tuq3a
================================================== ==========================

I am wondering why the portal server disable the cache for authenticated user. Does any body know the reason?