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From: Andi Kleen <andi@firstfloor.org>
To: Ross Vandegrift <ross@kallisti.us>
Cc: Glenn Griffin <ggriffin.kernel@gmail.com>,
	Andi Kleen <andi@firstfloor.org>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Add IPv6 support to TCP SYN cookies
Date: Tue, 5 Feb 2008 21:11:06 +0100	[thread overview]
Message-ID: <20080205201106.GB26150@one.firstfloor.org> (raw)
In-Reply-To: <20080205192559.GA10573@kallisti.us>

> The problem is that any reasonably recent PC can generate enough
> forged SYN packets to overwhelm reasonable SYN queues on a much more
> powerful server.

Have you actually seen this with a recent kernel in the wild or are
you just talking theoretically?

Linux uses some heuristics to manage the syn queue that should
still ensure reasonable service even without cookies under attack.
Also SYN-RECV sockets are stored in a special data structure optimized
to use minimal resources.

It is far from the classical head drop method that was so vunerable
to syn flooding.

-Andi

  reply	other threads:[~2008-02-05 19:36 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-04 23:01 Glenn Griffin
2008-02-05 15:55 ` Andi Kleen
2008-02-05 15:42   ` Alan Cox
2008-02-05 16:39     ` Andi Kleen
2008-02-05 16:03       ` Alan Cox
2008-02-05 16:48         ` Andi Kleen
2008-02-05 16:14           ` Alan Cox
2008-02-05 20:50       ` Willy Tarreau
2008-02-05 18:29   ` Glenn Griffin
2008-02-05 19:25     ` Ross Vandegrift
2008-02-05 20:11       ` Andi Kleen [this message]
2008-02-05 21:23         ` Ross Vandegrift
2008-02-06  8:53           ` Andi Kleen
2008-02-07 19:44             ` Ross Vandegrift
2008-02-08 12:07               ` Andi Kleen
2008-02-12 20:38                 ` Ross Vandegrift
2008-02-05 20:02     ` Andi Kleen
2008-02-05 20:39       ` Evgeniy Polyakov
2008-02-05 20:53         ` Andi Kleen
2008-02-05 21:50           ` Evgeniy Polyakov
2008-02-05 21:20         ` Alan Cox
2008-02-05 21:52           ` Evgeniy Polyakov
2008-02-05 21:20             ` Willy Tarreau
2008-02-05 22:05             ` Alan Cox
2008-02-06  1:52               ` Glenn Griffin
2008-02-06  7:50                 ` Andi Kleen
2008-02-06 17:36                   ` Glenn Griffin
2008-02-06 18:45                     ` Andi Kleen
2008-02-06 23:03                       ` Glenn Griffin
2008-02-06  9:13                 ` Evgeniy Polyakov
2008-02-06 18:30                   ` Glenn Griffin
2008-02-07  7:24                     ` Evgeniy Polyakov
2008-02-07  9:40                       ` Eric Dumazet
2008-02-08  5:32                         ` Glenn Griffin
2008-02-08  5:49                           ` Glenn Griffin
2008-02-11 16:07                             ` YOSHIFUJI Hideaki / 吉藤英明
2008-02-18 23:45                               ` Glenn Griffin
2008-02-13  7:31                         ` YOSHIFUJI Hideaki / 吉藤英明
2008-02-05 19:57   ` Jan Engelhardt
2008-02-05 21:25     ` Alan Cox
2008-02-04 23:01 Glenn Griffin

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