Re: Recent Facebook Issues

Peter Dey wrote:
> On Fri, Oct 09, 2009 at 12:56:59PM +1300, Amos Jeffries wrote:
>> going through the login redirects to the page also presented at (3) above.
>>
>> The home page is the real problem. When cookies are presented it ships
>> without Content-Length (fine).
>> When they _are_ present, ie after the user has logged in it ships with
>> Content-Length: 18487 and data size of 18576.
>
> I'd be interested to know what the symptoms you're experiencing are.

one reporter sees truncated pages. Three others so far (myself included)
see no page at all. Squid is receiving the excess data and closing the
connection before getting a chance to send anything to the client.

>
> I'm getting the following (tested in Debian's Squid 2.6.5-6etch4 and Squid
> 3.0.STABLE19-1) with Firefox 3.5 and IE7:
>
> * Login page shows. Login works fine.
> * Redirects to home page (i presume that's your (3) above)
>
> About 50% of the time, this home page will be blank. Shift-reload in Firefox
> doesn't seem to fix it (shift-reloading 8-10 times seems to eventually display
> the content).

Exactly our symptoms, though for me its more like 70%-80% blank. I'm
suspecting its maybe some but not all of their intermediate access
points are faulty. Due to the non-consistent nature of the one page.

>
> The problem's not restricted to the home page -- other pages, e.g. profile
> pages also get the "blank page" issue.

Okay, thanks for that. I've only isolated it for the home page since
thats easy to get to without sending any login details.

>
> I've tried the "chunked decoding" hack described here:
> http://squidproxy.wordpress.com/2008/04/29/chunked-decoding/
> without any luck.
>
> I've also attempted some of the other suggestions e.g. disabling persistent
> connections (both client and proxy) with no luck.
>
> Strangely, the problem only started occurring maybe around 2 months ago (when I
> was running a squid 2.x variant).
>
> Cheers,
> Peter

The problems is pretty clearly something either generated by their end
or by a proxy in the middle doing something it should not. The ones
seeing the problem are bystanders being caught in the middle.

The involvement of chunked here is not that they are using it, (the
wordpress article is about disabling chunks) but that the facebook
system only works reliably now when chunks _are_ used to what it thinks
is a HTTP/1.1 peer (its a violation for Squid to advertise that).

Disabling persistent connections will limit the collateral damage when
none of the links dies, but not resolve or even hide the actual issue.

Amos

-- 
Please be using
   Current Stable Squid 2.7.STABLE7 or 3.0.STABLE19
   Current Beta Squid 3.1.0.14