Libre site down, again

Libre site down, again

[Tapani Rundgren]

libre.adacore.com seems to be down?
Does anybody know why?

Kind Regards,
Tapani Rundgren

Re: Libre site down, again

[Pascal Obry]

Tapani Rundgren a �crit :
> libre.adacore.com seems to be down?
> Does anybody know why?

Working for me. A colleague of mine has/had some problems to access
Libre recently. Maybe a DNS problem somewhere...

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.net
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595

Re: Libre site down, again

[Björn Persson]

Tapani Rundgren wrote:
> libre.adacore.com seems to be down?
> Does anybody know why?

It doesn't seem to be any more broken than usual to me. That is, the 
defective firewall is still there but the site works fine once I turn 
TCP window scaling off.

-- 
Bj�rn Persson                              PGP key A88682FD
                    omb jor ers @sv ge.
                    r o.b n.p son eri nu

Re: Libre site down, again

[Tapani Rundgren]

> It doesn't seem to be any more broken than usual to me. That is, the
> defective firewall is still there but the site works fine once I turn
> TCP window scaling off.
>
> --
> Björn Persson                              PGP key A88682FD
>                     omb jor ers @sv ge.
>                     r o.b n.p son eri nu

Thanks, Björn!
That solved the problem.

/Tapani

Re: Libre site down, again

[Pascal Obry]

Bj�rn Persson a �crit :
> It doesn't seem to be any more broken than usual to me. That is, the
> defective firewall is still there but the site works fine once I turn
> TCP window scaling off.

What is this (TCP window scaling?) ? How to turn that off ?

Thanks,
Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.net
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595

Re: Libre site down, again

[Björn Persson]

Pascal Obry wrote:
> What is this (TCP window scaling?) ?

In short, it's an extension to TCP (the Transmission Control Protocol) 
to enable efficient use of a high bandwidth. It's fully backward 
compatible as long as all devices follow the TCP standard, but some 
firewalls violate the standard and mess up extension fields that they 
don't understand. Google can tell you more.

> How to turn that off ?

That depends on the operating system. On Linux 2.6 I do:

echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

You seem to be running some form of Windows. I don't even know whether 
Windows can use window scaling, much less how to tweak it.

-- 
Bj�rn Persson                              PGP key A88682FD
                    omb jor ers @sv ge.
                    r o.b n.p son eri nu

Re: Libre site down, again

[Pascal Obry]

Bj�rn,

> That depends on the operating system. On Linux 2.6 I do:
> 
> echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

Thanks.

> You seem to be running some form of Windows. I don't even know whether
> Windows can use window scaling, much less how to tweak it.

Yes I'm running Windows most of the time. I have this problem neither on
my Windows box nor on my GNU/Linux box... I was just curious :)

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.net
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595

Re: Libre site down, again

[Olivier Ramonat]

Pascal Obry <pascal@obry.net> writes:

> Björn,
>
>> That depends on the operating system. On Linux 2.6 I do:
>> 
>> echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

Thanks, that solved the problem on my Debian GNU/Linux box (2.6.17) !

But how many GNU/Linux users are unable to connect to libre.adacore ?

--
Olivier Ramonat
gpg --keyserver wwwkeys.pgp.net --recv-key 012A5DC8

Re: Libre site down, again

[deadlyhead]

>
> Thanks, that solved the problem on my Debian GNU/Linux box (2.6.17) !
>
> But how many GNU/Linux users are unable to connect to libre.adacore ?
>

I actually had this problem when I upgraded my kernel to the latest
release.  I didn't know about tcp_window_scaling at that time, so now
I'm back to running 2.6.16.

The strange thing is, running a 2.6.16 kernel as I am now,
tcp_window_scaling is set to 1, but I can access libre just fine.
Makes me wish I knew more about the Linux kernel.  Time to get serious
about AdaOS, I suppose.

--Seth

Re: Libre site down, again

[Björn Persson]

Someone claiming to be a lethal noddle wrote:
> The strange thing is, running a 2.6.16 kernel as I am now,
> tcp_window_scaling is set to 1, but I can access libre just fine.

They changed the calculation of TCP buffer sizes. I think the point was 
to make better use of available memory. If there's plenty of memory, 
then Linux can afford to allocate a large buffer so that the sender can 
keep the pipe full of packets, and a large buffer requires a large scale 
factor. But the larger the scale factor is, the more hindered the 
communication is when these broken boxes mangle it. If a small scale 
factor gets mangled, your buffer will seem smaller than it is but the 
connection can still limp along. If a large scale factor gets mangled, 
the connection freezes completely.

-- 
Bj�rn Persson                              PGP key A88682FD
                    omb jor ers @sv ge.
                    r o.b n.p son eri nu

Re: Libre site down, again

[Samuel Tardieu]

>>>>> "Seth" == deadlyhead  <s.brutzman@gmail.com> writes:

Seth> The strange thing is, running a 2.6.16 kernel as I am now,
Seth> tcp_window_scaling is set to 1, but I can access libre just
Seth> fine.  Makes me wish I knew more about the Linux kernel.  Time
Seth> to get serious about AdaOS, I suppose.

Let's get this straight though: this is *not* a Linux bug. However,
some broken boxes and routers do not correctly handle TCP window
scaling. TCP window scaling is important to get the maximum throughput
on TCP connections.

If you run a Linux kernel 2.6.18-rc5 or above (such as 2.6.18), you
can work around this problem for specific sites (rather than hurting
TCP performances globally using the aforementionned sysctl) by doing:

# route add -net 212.157.227.0 netmask 255.255.255.0
  gw 192.168.0.254 window 65535

(all on one line, replace 192.168.0.254 with your default router address)

Also note that TCP window scaling has been defined in RFC 1323 back in
1992...

  Sam
-- 
Samuel Tardieu -- sam@rfc1149.net -- http://www.rfc1149.net/

Re: Libre site down, again

[Thomas Quinot]

Samuel Tardieu wrote:

> Let's get this straight though: this is *not* a Linux bug. However,
> some broken boxes and routers do not correctly handle TCP window
> scaling. TCP window scaling is important to get the maximum throughput
> on TCP connections.

Sam,

Thank you for bringing this issue to our attention. We have identified
and corrected an issue on our networking equipment that could cause the 
described problem. Linux clients that use TCP window scaling should
now be able to communicate with libre.adacore.com.

Thomas.

Re: Libre site down, again

[Björn Persson]

Thomas Quinot wrote:
> Sam,
> 
> Thank you for bringing this issue to our attention.

Well thank *you* for totally ignoring me when I tried to bring this 
issue to your attention over three months ago. I sent you an email on 
the sixth of July where I described the problem in detail, and I got no 
reaction whatsoever. The problem has also been mentioned here in 
comp.lang.ada several times before.

-- 
Bj�rn Persson                              PGP key A88682FD
                    omb jor ers @sv ge.
                    r o.b n.p son eri nu