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Posted to dev@httpd.apache.org by Graham Leggett <mi...@sharp.fm> on 2002/01/29 23:35:58 UTC
A question for the protocol gurus...
Hi all,
On the proxy list there is talk of support for transparent-proxy
behaviour, and the question has come up "what about HTTP/0.9?". Am I
correct in saying it is not possible to find the destination server if
the protocol is v0.9 or v1.0, and there is no host header, and there is
no complete URL in the request (ie http://server.name/blah instead of
just /blah)? Or is there some trick to do this?
Regards,
Graham
--
-----------------------------------------
minfrin@sharp.fm "There's a moon
over Bourbon Street
tonight..."
Re: A question for the protocol gurus...
Posted by Graham Leggett <mi...@sharp.fm>.
"Roy T. Fielding" wrote:
> It can fail however it likes -- transparent gateways are not allowed in HTTP.
> Once you violate the protocol, you are doomed to any number of unspecified
> workarounds that will ultimately fail outside the common case.
Makes sense.
Regards,
Graham
--
-----------------------------------------
minfrin@sharp.fm "There's a moon
over Bourbon Street
tonight..."
Re: A question for the protocol gurus...
Posted by "Roy T. Fielding" <fi...@ebuilt.com>.
> But in theory this could also happen with HTTP/1.0 if a client asks for
> /blah and doesn't include a host header - in this case the gateway has
> no way of figuring out who to connect to, and must fail as I understand
> it with "505 Upgrade Dammnit". Am I right?
It can fail however it likes -- transparent gateways are not allowed in HTTP.
Once you violate the protocol, you are doomed to any number of unspecified
workarounds that will ultimately fail outside the common case.
....Roy
Re: A question for the protocol gurus...
Posted by Graham Leggett <mi...@sharp.fm>.
"Roy T. Fielding" wrote:
> On Tue, Jan 29, 2002 at 09:25:24PM -0500, Chuck Murcko wrote:
> > So as Graham said proxy should reply 501 or 505 right?
>
> It doesn't matter -- HTTP/0.9 responses don't have error codes.
> You just have to return an HTML page that tells the user to get out
> of their rocking chair and upgrade the client application to a modern
> version of HTTP.
But in theory this could also happen with HTTP/1.0 if a client asks for
/blah and doesn't include a host header - in this case the gateway has
no way of figuring out who to connect to, and must fail as I understand
it with "505 Upgrade Dammnit". Am I right?
Regards,
Graham
--
-----------------------------------------
minfrin@sharp.fm "There's a moon
over Bourbon Street
tonight..."
Re: A question for the protocol gurus...
Posted by "Roy T. Fielding" <fi...@ebuilt.com>.
On Tue, Jan 29, 2002 at 09:25:24PM -0500, Chuck Murcko wrote:
> So as Graham said proxy should reply 501 or 505 right?
It doesn't matter -- HTTP/0.9 responses don't have error codes.
You just have to return an HTML page that tells the user to get out
of their rocking chair and upgrade the client application to a modern
version of HTTP.
....Roy
Re: A question for the protocol gurus...
Posted by Chuck Murcko <ch...@topsail.org>.
So as Graham said proxy should reply 501 or 505 right?
Chuck
On Tuesday, January 29, 2002, at 05:47 PM, Roy T. Fielding wrote:
>> On the proxy list there is talk of support for transparent-proxy
>> behaviour, and the question has come up "what about HTTP/0.9?". Am I
>> correct in saying it is not possible to find the destination server if
>> the protocol is v0.9 or v1.0, and there is no host header, and there is
>> no complete URL in the request (ie http://server.name/blah instead of
>> just /blah)? Or is there some trick to do this?
>
> It is not possible to use a proxy with HTTP/0.9. It is possible to use
> a gateway, so those requests should be interpreted as local paths.
> A transparent proxy is a gateway (that transparent-proxy term is bogus
> and should not be used by us).
>
> ....Roy
>
>
Re: A question for the protocol gurus...
Posted by "Roy T. Fielding" <fi...@ebuilt.com>.
> On the proxy list there is talk of support for transparent-proxy
> behaviour, and the question has come up "what about HTTP/0.9?". Am I
> correct in saying it is not possible to find the destination server if
> the protocol is v0.9 or v1.0, and there is no host header, and there is
> no complete URL in the request (ie http://server.name/blah instead of
> just /blah)? Or is there some trick to do this?
It is not possible to use a proxy with HTTP/0.9. It is possible to use
a gateway, so those requests should be interpreted as local paths.
A transparent proxy is a gateway (that transparent-proxy term is bogus
and should not be used by us).
....Roy
Re: A question for the protocol gurus...
Posted by Eli Marmor <ma...@netmask.it>.
Graham Leggett wrote:
> On the proxy list there is talk of support for transparent-proxy
> behaviour, and the question has come up "what about HTTP/0.9?". Am I
> correct in saying it is not possible to find the destination server if
> the protocol is v0.9 or v1.0, and there is no host header, and there is
> no complete URL in the request (ie http://server.name/blah instead of
> just /blah)? Or is there some trick to do this?
Let me add one more important detail:
It is assumed that the packets were manipulated by a DNAT engine (such
as iptables) to reach the proxy on this host, rather than just passing
this host on their way to the original hosts.
So I don't think it is possible to look at the destination IP address
(unless the original one is kept somewhere else in the packets...)
--
Eli Marmor
marmor@netmask.it
CTO, Founder
Netmask (El-Mar) Internet Technologies Ltd.
__________________________________________________________
Tel.: +972-9-766-1020 8 Yad-Harutzim St.
Fax.: +972-9-766-1314 P.O.B. 7004
Mobile: +972-50-23-7338 Kfar-Saba 44641, Israel
Re: A question for the protocol gurus...
Posted by Tony Finch <do...@dotat.at>.
On Wed, Jan 30, 2002 at 12:35:58AM +0200, Graham Leggett wrote:
>
> On the proxy list there is talk of support for transparent-proxy
> behaviour, and the question has come up "what about HTTP/0.9?". Am I
> correct in saying it is not possible to find the destination server if
> the protocol is v0.9 or v1.0, and there is no host header, and there is
> no complete URL in the request (ie http://server.name/blah instead of
> just /blah)? Or is there some trick to do this?
When transparent proxying you use a trick (usually a special in-kernel
firewall config) to accept connections to any IP address, and you use
the destination address of the connection to determine which upstream
server to forward the request to.
The only time you get a complete URL in the request is if the browser
is configured to use a proxy, which is not the case for transparent
proxying (unless you are putting the transparent proxy in front of
a proxy, but that's mad).
Tony.