W3C home > Mailing lists > Public > public-tracking@w3.org > November 2011

Re: Issue-4

From: Ronan Heffernan <ronansan@gmail.com>
Date: Wed, 9 Nov 2011 11:32:09 -0500
Message-ID: <CAHyiW9Jd4BEM=TveGM=eOProbu4feiZVEaBkSm4wOVK__CoJ6g@mail.gmail.com>
To: Tracking Protection Working Group WG <public-tracking@w3.org>
> Can anyone come up with a use case here?

Having a "DNT not set" header would allow a webserver to detect that a DNT
header had been stripped-off by an intermediary (router, proxy, etc.), if
it maintains a list of user-agent-strings that are known to always send DNT
headers (even if the value is 'not set').  This would allow the webserver
to treat a request with a stripped-off header differently (perhaps applying
DNT? perhaps warning the user?) from a request that came from a browser
that was known to not support the DNT feature.

Similarly, if a response (either from a header or well-known URI)
echoes-back the received DNT setting, then having "missing" distinct from
"received as 'not set'" would allow the browser to detect that an
intermediary (proxy, router, etc.) had stripped-off the user's DNT header,
even in the case where it was not set.

--Ronan Heffernan


On Wed, Nov 9, 2011 at 2:52 AM, Aleecia M. McDonald <aleecia@aleecia.com>wrote:

On Nov 8, 2011, at 6:42 PM, David Singer wrote:

[ůsnipů]

> "We noticed your header was missing, or set explicitly to "declined to
state".  There are advantages to an explicit statementů"

This is what I am trying to understand. What advantages would there be for
an explicit statement that DNT is not set? We already know there will be
many users with older browsers that cannot (readily) set DNT for some time
to come while they slowly upgrade, so sites getting DNT signals have to
deal with the unset case no matter what. What does an explicit "not stated"
setting have as an advantage over not sending anything? Can anyone come up
with a use case here?

       Aleecia



On Wed, Nov 9, 2011 at 2:52 AM, Aleecia M. McDonald <aleecia@aleecia.com>wrote:

>
> On Nov 8, 2011, at 6:42 PM, David Singer wrote:
>
> [ůsnipů]
>
> > "We noticed your header was missing, or set explicitly to "declined to
> state".  There are advantages to an explicit statementů"
>
> This is what I am trying to understand. What advantages would there be for
> an explicit statement that DNT is not set? We already know there will be
> many users with older browsers that cannot (readily) set DNT for some time
> to come while they slowly upgrade, so sites getting DNT signals have to
> deal with the unset case no matter what. What does an explicit "not stated"
> setting have as an advantage over not sending anything? Can anyone come up
> with a use case here?
>
>        Aleecia
>
Received on Wednesday, 9 November 2011 16:33:09 UTC

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