I like your analysis and I share your frustration.
And this is a so bad press for inria.

Stef

On Thu, Nov 23, 2017 at 2:49 PM, Norbert Hartl <[email protected]> wrote:
>
>
> Am 23.11.2017 um 13:18 schrieb Christophe Demarey
> <[email protected]>:
>
>
> Le 23 nov. 2017 à 12:34, Norbert Hartl <[email protected]> a écrit :
>
>
>
> Am 23.11.2017 um 11:39 schrieb Christophe Demarey
> <[email protected]>:
>
> Hi Norbert,
>
> I understand your point of view that others probably share.
> I also agree the situation is very bad: Inria took too much time to
> investigate the problem and now, renater also …
> The question is: would it be really better outside Inria? Maybe ... maybe
> not …
>
>
> Maybe that is the point. It is not a question if it works better outside
> because it will. The problem we have is so serious that it will be hard to
> find elsewhere. I can only repeat: It is not the download that fails which
> TCP wise means that exactly the thing is downloaded that inria offered. So
> something below the web server is broken and most probably they have a
> corrupt storage solution meaning only if you give it broken to the web
> server the broken thing can be transported in a sane manner.
>
>
> I’m not confident with the diagnostic.
> I never encountered this problem and we got no such feedback from people in
> the team. So it is really strange. Indeed, if CRC is worn it does not mean
> slowness but corrupted data … I do not see any reason that we do have CRC
> from outside Inria but not inside.
> If no solution is found today or tomorrow, we will probably see to host a
> solution outside Inria.
>
>
> If you are not confident about the diagnosis that's fine. But then it would
> be cool to come up with a better one and not giving that "works for me".
> That is not an explanation. Because your assumption would be that externally
> and internally you use the same system and transport ways. And that is most
> likely not true.
> Just try to find an explanation. Here we go:
>
> - If I download a zip file from files.pharo.org I open a TCP connection from
> my laptop to files.pharo.org
> - TCP has a checksum in the header that is used to check the integrity of
> each transferred package
> - So I can assume that this packet of the one connection was not tampered
> - If it counts for a single packet it counts for the whole file
> - With all my assumption I can state that I get exactly what the
> files.pharo.org is sending me
>
> So what are the possibilities it fails?
>
> - Either the stack beneath hands out the data to the TCP stack delivers
> corrupt data. That could be the filesystem hence my thought
> - Or there is no single connection between my laptop and files.pharo.org. In
> that case the data would flow over a proxy. But even if I have two
> connections and for each the integrity check counts then what I said for one
> connection counts for two and more as well
> - If we really decline beliving the filesystem fails (that is less likely if
> it works inside of inria)
> - Is there anything left? Yes, if the proxy modifies the data you can have
> data integrity on the first connection, then a program that deliberately
> changes the content and transfers that integer again over the second
> connection. So it can be broken on the other end.
>
> If we then look at the file we might recognize that it has the ending .zip
> and this is the file type that transfers most viruses over the net. So we
> even can imagine what kind of proxy that might be, let's call it a virus
> checker. That is what I would do in order to narrow the problem.
>
> Norbert
>

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