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Re: multiplexing -- don't do it

From: Mike Belshe <mike@belshe.com>
Date: Mon, 2 Apr 2012 14:20:51 -0700
Message-ID: <CABaLYCuqLQb4n+CTx85qXisKFahpPs=dNt4ePPi5cXaS6OCpVA@mail.gmail.com>
To: Peter Lepeska <bizzbyster@gmail.com>
Cc: ietf-http-wg@w3.org
On Mon, Apr 2, 2012 at 2:15 PM, Peter Lepeska <bizzbyster@gmail.com> wrote:

> " Further, proxies today already need this solution, even without SPDY.
>  Traffic is moving to SSL already, albeit slowly, and corporate firewalls
> can't see it today.  Corporate firewall admins are forced to do things like
> block facebook entirely to prevent data leakage.  But, with this solution,
> they could allow facebook access and still protect their IP.  (Or they
> could block it if they wanted to, of course). "
>
> I don't understand how your HTTPS proxy will fix this since facebook
> itself will still be HTTPS. So with your proxy its SSL in SSL tunnel.
>

I was trying to describe https to the proxy, which breaks the SSL, and then
initiates a new SSL connection to FB.

I call this a "trusted proxy".  The browser in this case must have
explicitly specified the proxy to use and also that it is okay to let it
break SSL.

Mike




>
> The proxy can still not see the facebook traffic in the clear so the admin
> will still either need to block facebook entirely or do a MITM.
>
> Peter
>
> On Mon, Apr 2, 2012 at 5:11 PM, Mike Belshe <mike@belshe.com> wrote:
>
>>
>>
>> On Mon, Apr 2, 2012 at 2:08 PM, Adrien W. de Croy <adrien@qbik.com>wrote:
>>
>>>
>>> ------ Original Message ------
>>> From: "Mike Belshe" <mike@belshe.com>
>>> To: "Adrien W. de Croy" <adrien@qbik.com>
>>> Cc: "Amos Jeffries" <squid3@treenet.co.nz>;"ietf-http-wg@w3.org" <
>>> ietf-http-wg@w3.org>
>>> Sent: 3/04/2012 8:52:22 a.m.
>>> Subject: Re: multiplexing -- don't do it
>>>
>>>
>>>
>>> On Mon, Apr 2, 2012 at 1:43 PM, Adrien W. de Croy < <adrien@qbik.com>
>>> adrien@qbik.com> wrote:
>>>
>>>>
>>>> ------ Original Message ------
>>>> From: "Mike Belshe" <mike@belshe.com>mike@belshe.com
>>>>
>>>>
>>>>
>>>> On Mon, Apr 2, 2012 at 6:57 AM, Amos Jeffries < <squid3@treenet.co.nz><squid3@treenet.co.nz>
>>>> squid3@treenet.co.nz> wrote:
>>>>
>>>>> On 1/04/2012 5:17 a.m., Adam Barth wrote:
>>>>>
>>>>> On Sat, Mar 31, 2012 at 4:54 AM, Mark Nottingham wrote:
>>>>>>
>>>>>>> On 31/03/2012, at 1:11 PM, Mike Belshe wrote:
>>>>>>>
>>>>>>> For the record - nobody wants to avoid using port 80 for new
>>>>>>>> protocols.  I'd love to!  There is no religious reason that we don't - its
>>>>>>>> just that we know, for a fact, that we can't do it without subjecting a
>>>>>>>> non-trivial number of users to hangs, data corruption, and other errors.
>>>>>>>>  You might think its ok for someone else's browser to throw reliability out
>>>>>>>> the window, but nobody at Microsoft, Google, or Mozilla has been willing to
>>>>>>>> do thatů
>>>>>>>>
>>>>>>> Mike -
>>>>>>>
>>>>>>> I don't disagree on any specific point (as I think you know), but I
>>>>>>> would observe that the errors you're talking about can themselves be viewed
>>>>>>> as transient. I.e., just because they occur in experiments now, doesn't
>>>>>>> necessarily mean that they won't be fixed in the infrastructure in the
>>>>>>> future -- especially if they generate a lot of support calls, because they
>>>>>>> break a lot MORE things than they do now.
>>>>>>>
>>>>>>> Yes, there will be a period of pain, but I just wanted to highlight
>>>>>>> one of the potential differences between deploying a standard and a
>>>>>>> single-vendor effort.  It's true that we can't go too far here; if we
>>>>>>> specify a protocol that breaks horribly 50% of the time, it won't get
>>>>>>> traction. However, if we have a good base population and perhaps a good
>>>>>>> fallback story, we *can* change things.
>>>>>>>
>>>>>> That's not our experience as browser vendors.  If browsers offer an
>>>>>> HTTP/2.0 that has a bad user experience for 10% of users, then major
>>>>>> sites (e.g., Twitter) won't adopt it.  They don't want to punish their
>>>>>> users any more than we do.
>>>>>>
>>>>>> Worse, if they do adopt the new protocol, users who have trouble will
>>>>>> try another browser (e.g., one that doesn't support HTTP/2.0 such as
>>>>>> IE 9), observe that it works, and blame the first browser for being
>>>>>> buggy.  The net result is that we lose a user and no pressure is
>>>>>> exerted on the intermediaries who are causing the problem in the first
>>>>>> place.
>>>>>>
>>>>>> These are powerful market force that can't really be ignored.
>>>>>>
>>>>>
>>>>> So the takeway there is pay attention to the intermediary people when
>>>>> they say something cant be implemented (or won't scale reasonably).
>>>>>
>>>>
>>>> I agree we should pay attention to scalability - and we have.
>>>>
>>>> Please don't disregard that Google servers switched to SPDY with zero
>>>> additional hardware (the google servers are fully conformant http/1.1
>>>> proxies with a lot more DoS logic than the average site).  I know, some
>>>> people think Google is some magical place where scalability defies physics
>>>> and is not relevant, but this isn't true.  Google is just like every other
>>>> site, except much much bigger.   If we had a 10% increase in server load
>>>> with SPDY, Google never could have shipped it.  Seriously, who would roll
>>>> out thousands of new machines for an experimental protocol?  Nobody.  How
>>>> would we have convinced the executive team "this will be faster", if they
>>>> were faced with some huge cap-ex bill?  Doesn't sound very convincing, does
>>>> it?  In my mind, we have already proven clearly that SPDY scales just fine.
>>>>
>>>> But I'm open to other data.  So if you have a SPDY implementation and
>>>> want to comment on the effects on your server, lets hear it!   And I'm not
>>>> saying SPDY is free.  But, when you weigh costs (like compression and
>>>> framing) against benefits (like 6x fewer connections),  there is no
>>>> problem.  And could we make improvements still?  Of course.  But don't
>>>> pretend that these are the critical parts of SPDY.  These are the mice nuts.
>>>>
>>>>
>>>> For a forward proxy, there are several main reasons to even exist:
>>>>
>>>> a) implement and enforce access control policy
>>>> b) audit usage
>>>> c) cache
>>>>
>>>> you block any of these by bypassing everything with TLS, you have a
>>>> non-starter for corporate environments.  Even if currently admins kinda
>>>> turn a blind eye (because they have to) and allow port 443 through, as more
>>>> and more traffic moves over to 443, more pressure will come down from
>>>> management to control it.
>>>>
>>>> Best we don't get left with the only option being MITM.
>>>>
>>>
>>> In my talk at the IETF, I proposed a solution to this.
>>>
>>> Browsers need to implement SSL to trusted proxies, which can do all of
>>> the a/b/c that you suggested above.  This solution is better because the
>>> proxy becomes explicit rather than implicit.  This means that the user
>>> knows of it, and it IT guys knows of it.  If there are problems, it can be
>>> configured out of the system.  Implicit proxies are only known the the IT
>>> guy (maybe), and can't be configured out from a client.  The browser can be
>>> made to honor HSTS so that end-to-end encryption is always enforced
>>> appropriately.
>>>
>>> Further, proxies today already need this solution, even without SPDY.
>>>  Traffic is moving to SSL already, albeit slowly, and corporate firewalls
>>> can't see it today.  Corporate firewall admins are forced to do things like
>>> block facebook entirely to prevent data leakage.  But, with this solution,
>>> they could allow facebook access and still protect their IP.  (Or they
>>> could block it if they wanted to, of course).
>>>
>>> Anyway, I do agree with you that we need better solutions so that we
>>> don't incur more SSL MITM.  Many corporations are already looking for
>>> expensive SSL MITM solutions (very complex to rollout due to key
>>> management) because of the reasons I mention above, and its a technically
>>> inferior solution.
>>>
>>> So lets do it!
>>>
>>>
>>> I basically agree with all the above, however there is the ISP
>>> intercepting proxy to think about.
>>>
>>> Many ISPs here in NZ have them, it's just a fact of life when you're
>>> 150ms from the US and restricted bandwidth.  Pretty much all the big ISPs
>>> have intercepting caching proxies.
>>>
>>> There's just no way to make these work... period...
>>>
>>> unless the ISP is to
>>>
>>> a) try and support all their customers to use an explicit proxy, or
>>> b) get all their customers to install a root cert so they can do MITM.
>>>
>>
>>
>>> Maybe we need a better way to force a client to use a proxy, and take
>>> the pain out of it for administration.  And do it securely (just
>>> remembering why 305 was deprecated).
>>>
>>
>>  Do proxy pacs or dhcp work for this?
>>
>> Note that we also need the browsers to honor HSTS end-to-end, even if we
>> turn on "GET https://".
>> Mike
>>
>>
>>
>>
>>> Adrien
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> Mike
>>>
>>>
>>>
>>>
>>>>
>>>> Adrien
>>>>
>>>>
>>>>
>>>>
>>>> Mike
>>>>
>>>>
>>>>
>>>>> With plenty of bias, I agree.
>>>>>
>>>>> AYJ
>>>>>
>>>>>
>>>>
>>>
>>
>
Received on Monday, 2 April 2012 21:21:20 GMT

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