Re: Torrents killing my conection

[Stan Hoeppner <stan@hardwarefreak.com>]

Mark put forth on 6/21/2010 1:20 PM:
> On Mon, Jun 21, 2010 at 11:12 AM, Tim Clewlow <tim@clewlow.org> wrote:
> 
>>
>> I would still like to know the answer to one simple question.
>>
>> Does restarting the modem/router bring the network back up?
>>
>> If the answer is yes, then the problem is on the modem/router.
>>
> 
> How can this be true when the same machine, same hardware, different OS's
> downloads the torrent fine?  The modem/router/ISP is common to all
> situations here.  If the modem/router needs to be brought back up wouldn't
> it be because something in Debian or the non-working Ubuntu isn't handling
> the torrents properly?

I have a perl application that I use to pull rDNS names for all IPs in any
network up to a size /16 totally in parallel.  For a /16 query, the
application will send 65,536 _simultaneous_ UDP packets to remote DNS servers.
 This absolutely melts every consumer router on the market.  Some just stop
functioning and require a reboot.  Some have hard coded UDP flood protection
on both the public and private interfaces and simply drop excessive packets,
allowing "normal" UDP traffic to flow after a timeout period, usually a few
seconds to a minute or more.

I have a 2nd version of this perl application that sends the queries in
batches instead of all at once.  The batch size is configurable, allowing one
to "tickle the dragon" to find the settings that work fine just below the
melting point.

These applications behave slightly differently on different flavors of *nix
and with different versions of perl and different versions of the required
perl modules.

Thus, with the same router, I could take a few different *nix OS flavors and
perl versions, blowing up the router with some, and not denting it with others.

It's all about the packet load you push through the router.  It's absolutely
normal for setups that "seem" the same to nuke the router, because once you
peek under the hood, they aren't really behaving the same at all.

Take a peek under the hood. :)

-- 
Stan