W3C home > Mailing lists > Public > ietf-http-wg-old@w3.org > May to August 1995

Re: forged dates and other anti-cache practices

From: Benjamin Franz <snowhare@netimages.com>
Date: Wed, 16 Aug 1995 15:29:28 -0700 (PDT)
To: http wg discussion <http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com>
Message-Id: <Pine.LNX.3.91.950816145737.7494B-100000@ns.Viet.NET>
On Wed, 16 Aug 1995, Balint Nagy Endre wrote:

> Hi all,
> I'm here again, and want to summarise discussion on cache disabling
> techniques.
> Why people are against caching documents?
> 1. I can only guess intentions of people, never seen personally, but I can
> imagine only one cause: they want precise access statistics.

Shopping basket applications and dynamic documents. *FAR* more important 
than precise stats.

It never even occured to me that it might provide more precise access 
stats when I designed a site to explicitly defeat caching 
(<URL:http://www.psiloveyou.com/>, for those who care). The problem 
with caching is it makes dynamic documents (as in some shopping basket 
applications) hell. Between Mosiac's "Expire:? What's that?" behavior and 
cache corruption in Netscape, I couldn't run a reliable site without 
explicitly munging URLs to prevent caching in addition to expiring 
large sections of the site instantly. Believe me - I tried.

It wasn't until later discussion by people trying to claim AOL has 
millions of accesses hiding behind single hits to their proxies that it 
occured to me that it was also a way to defeat the stats unfriendly 
behavior of caching browsers/proxies. Incidentally, based on the stats 
from the cache defeating site - AOL undercounting is no more than a 
factor of two or three.  I would speculate that the massively broken 
nature of their browser, combined with a huge speed gap between 'Native 
AOL' graphics and inlined Web graphics turns AOLers off the WWW. Paying 
high per hour charges to download graphics from the web seems a 
no-brainer (to me anyway).

> 2. they aren't paying for non-cached and otherwise cacheable requests.

I am not at all sure how to parse this. At first I thought you meant that 
the provider charged by the hit, then I thought the opposite.

Could you clarify what you mean?

Benjamin Franz
Received on Wednesday, 16 August 1995 15:18:49 UTC

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