W3C home > Mailing lists > Public > ietf-http-wg@w3.org > July to September 2009

Re: #179: Relax Via MUST

From: Mark Nottingham <mnot@mnot.net>
Date: Fri, 17 Jul 2009 17:04:42 +1000
Cc: "Roy T. Fielding" <fielding@gbiv.com>, Henrik Nordstrom <henrik@henriknordstrom.net>, HTTP Working Group <ietf-http-wg@w3.org>
Message-Id: <7F3E2FE8-35EB-4090-BFEE-DE7DB136F195@mnot.net>
To: Adrien de Croy <adrien@qbik.com>

On 17/07/2009, at 5:05 PM, Adrien de Croy wrote:

>
> yes, I think many specific-application proxies don't put Via in,  
> probably for that reason.
>
> in fact I think many proxies also mirror the HTTP version they  
> received in the request through to the next hop.

Yes, that probably could use some emphasis as well.

>
> Transparent proxies are still required to insert Via?

If you mean intercepting, yes (although they're not really kosher,  
it's still necessary for them to do this if the various protocol  
features that depend upon it are going to function).


>
> Mark Nottingham wrote:
>> In the back of my head, I've actually been thinking it would be  
>> useful to note that Via is necessary for operation of some protocol  
>> features, which is why there's the option for a minimal Via header,  
>> e.g. "1.1 foo".
>>
>> I say this because I suspect that many implementers just don't  
>> realise that it has these uses. Of course, you're not going to  
>> dissuade the more paranoid folks from stripping anything that looks  
>> like intermediation, but oh well.
>>
>> Cheers,
>>
>>
>> On 17/07/2009, at 4:40 PM, Adrien de Croy wrote:
>>
>>>
>>> I think it might have been me that raised this issue a while back
>>>
>>> I agree it needs to be closed with no action.
>>>
>>> Taking it out breaks too much stuff.
>>>
>>> The original query related to customers who have unreasonable ISPs  
>>> who don't want customers to run proxies to get more use out of  
>>> their link, these customers didn't want there to be anything in  
>>> their HTTP requests that would give away the existence of a proxy.
>>>
>>> I think this case is probably best handled with an option (default  
>>> off) to make the proxy "stealthy", which strictly speaking makes  
>>> it broken (no outbound Via).  Inbound Via is another matter and  
>>> doesn't have any privacy issues.
>>>
>>> It's probably even less of an issue now with the prevalence of  
>>> proxies for other purposes, even running on the local machine  
>>> (e.g. some filtering / AV software installs a proxy for localhost).
>>>
>>> Thanks
>>>
>>> Adrien
>>>
>>>
>>> Roy T. Fielding wrote:
>>>> On Jul 16, 2009, at 5:13 PM, Mark Nottingham wrote:
>>>>
>>>>> I'm fine closing this with no action; IIRC the previous  
>>>>> discussion was leaning towards removing the requirement.
>>>>>
>>>>> Others?
>>>>
>>>> There is no way we can remove the requirement without removing
>>>> half a dozen other features.  Intermediaries that don't send
>>>> Via are broken and will continue to be broken even if the
>>>> requirement doesn't exist.
>>>>
>>>> ....Roy
>>>>
>>>>
>>>
>>> -- 
>>> Adrien de Croy - WinGate Proxy Server - http://www.wingate.com
>>>
>>
>>
>> -- 
>> Mark Nottingham     http://www.mnot.net/
>>
>>
>
> -- 
> Adrien de Croy - WinGate Proxy Server - http://www.wingate.com
>


--
Mark Nottingham     http://www.mnot.net/
Received on Friday, 17 July 2009 07:05:22 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 27 April 2012 06:51:07 GMT