Re: exit notation stripping

[Scott Bennett <bennett@xxxxxxxxxx>]

     On Fri, 10 Jul 2009 03:00:23 -0500 Drake Wilson <drake@xxxxxxxxxxxx>
wrote:
>Quoth Scott Bennett <bennett@xxxxxxxxxx>, on 2009-07-10 01:44:22 -0500:
>> Next, privoxy sends an HTTP GET request, which contains no hostname,
>> domainname, Nickname.exit, nor IP address through the connection to
>> the web server at the other end.
>
>Someone's either been living in HTTP/0.9 days or hasn't been reading
>the specs.  HTTP/1.1 requires a Host field because multiple domains
>may be hosted at one TCP endpoint, and that's exactly the problem: the
>full URI is (albeit in pieces) passed through the whole way at the
>application layer, and the exit notation is included in the URI.  A
>full example flow is:
>
>  - Browser sends GET http://example.net.example.exit/ to an HTTP proxy
>    that is not aware of exit notation.
>
>  - The HTTP proxy connects to the Tor SOCKS proxy, requesting a
>    connection to example.net.example.exit.
>
>  - Tor builds its circuit and makes the connection.
>
>  - The HTTP proxy passes through GET http://example.net.example.exit/
>    to the origin server.
>
>  - The origin server looks up whether it knows of any site to serve
>    under "example.net.example.exit", finds that it doesn't, and
>    returns an error.  Alternatively, it uses a default site, which
>    may be the wrong one.  Alternatively, it does whatever it usually
>    does but now has mostly-definitive information that this user is
>    using Tor and has requested a specific exit node.
>
>This is why Privoxy includes a filter to strip the exit notation from
>the Host header when passing the request through, and why this filter
>should be enabled when using Privoxy for Tor purposes.
>
     Okay.  Thanks for the correction and explanation.  I guess it has
been a while.


                                  Scott Bennett, Comm. ASMELG, CFIAG
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