On Wed, 23 Jun 1999 19:09:09 +0100, <dforster@cisco.com> wrote:
>Ian,
>
>I don't quite see the difference between the WPAD case you cite and the
>case where the
>IS Department pre-configures my browser with a PAC URL. It seems to me that
>in both cases the existence of the proxy is similarly unknown to the
>content-consumer (and upper layers of the browser).
Agreed. Although the use of WPAD could remove any stored
configuration information as to the location of the PAC (so it's a
little bit more invisible). [E.g. you could force the use of WPAD by
not allowing people to turn it off, thereby forcing them into whatever
caching scheme is being employed by any PAC that is loaded.]
> In both cases it is
>possible (I assume this is true for a WPAD-enabled browser?) to determine
>the use of a proxy if one takes the trouble.
True, and it's also possible to detect the presence of a proxy with a
traffic intercepting environment.
But that's a case where you actually take the trouble to find out if a
proxy is in place. For the most part, the use of a PAC (obtained by
whatever means) to direct requests to a proxy on a per-request basis,
and the use of an intercepting network element (or perhaps an in-line
traffic intercepting proxy) to direct the traffic to an out-of-path
transparent proxy results in the content consumer having the same
experience[0].
> In summary I'm not convinced
>that auto-discovery introduces "transparency".
I think the discussion here identifies that there are a lot of
different understandings of that one key word and where it can be used
to have particular meaning. That's good, because it shows that we
need to be careful in fully documenting things in the taxonomy
(although it now makes my job rather hard :( ).
[0] The difference is in how protocols are used, and what data
traverses the network.
Ian
This archive was generated by hypermail 2b29 : Thu Nov 18 2004 - 11:21:26 MST