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From: Eric Dumazet <eric.dumazet@gmail.com>
To: 叶雨飞 <sunyucong@gmail.com>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: IPv4 route cache DOS attack
Date: Tue, 27 Nov 2012 17:01:14 -0800	[thread overview]
Message-ID: <1354064474.14302.44.camel@edumazet-glaptop> (raw)
In-Reply-To: <CAJygYd1OSTfpdbA57q0c6ppMtft3iB7uzo-RCXFOamGp2XVzBg@mail.gmail.com>

On Tue, 2012-11-27 at 15:15 -0800, 叶雨飞 wrote:
> Hi,
> 
> I have a linux router running kernel 3.2  that receive public ingress
> packets and route them through an GRE tunnel, return packets don't go
> through it
> 
> I've recently faced a serious issue with the route cache,  when the
> router received spoofed source , the route cache will quickly get
> exhausted (depending on the size of it) and soon the ip dst cache
> overflow will be printed and network subsystem will hang until
> restarted.
> 
> So, my question is, how can I turn off the route cache without
> recompile the kernel or adding the  patch for removal  in 3.7?  I
> tried to set
> 
> echo 0 > /proc/sys/net/ipv4/route/max_size but that has no effect at all.
> 
> And if some one can share some insight on why when dst cache
> overflows, the network subsystem hangs, it would be great.

echo -1 >/proc/sys/net/ipv4/rt_cache_rebuild_count

  reply	other threads:[~2012-11-28  1:01 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-27 23:15 IPv4 route cache DOS attack 叶雨飞
2012-11-28  1:01 ` Eric Dumazet [this message]
2012-11-28  1:34   ` 叶雨飞
2012-11-28  2:14 ` David Miller
2012-11-28  2:48   ` 叶雨飞

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