netdev - Re: DoS by cat /proc/net/ip

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Date:	Sat, 08 Mar 2008 13:26:41 +0100
From:	Jarek Poplawski <jarkao2@...il.com>
To:	Krzysztof Oledzki <olel@....pl>
CC:	Denys Fedoryshchenko <denys@...p.net.lb>, netdev@...r.kernel.org
Subject: Re: DoS by cat /proc/net/ip_conntrack ?

Krzysztof Oledzki wrote, On 03/06/2008 02:51 PM:

> 
> On Thu, 6 Mar 2008, Denys Fedoryshchenko wrote:

...

>> i tried to issue command cat /proc/net/ip_conntrack |grep 'something'
>>
>> Router went dead for about 2 minutes, even i disconnect ssh session.
...
>> I dont think it is normal, and such command taking a lot of system resources
>> and cause whole system to hang.
>>
>> Kernel 2.6.24.2
> 
> The answer is quite simple here: don't do this. Instead use "conntrack -L" 
> as netlink is much more effective and better designed.

I think, Denys is concerned about some other, maybe too curious users
if they can read this?

Regards,
Jarek P.
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