Date: Wed, 6 Feb 2008 00:52:17 +0300
From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>,
       Glenn Griffin <ggriffin.kernel@gmail.com>, netdev@vger.kernel.org,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Add IPv6 support to TCP SYN cookies
Message-ID: <20080205215216.GB24275@2ka.mipt.ru>
References: <47a79d64.16538c0a.5b6a.ffffb0fe@mx.google.com> <20080205155558.GA23145@one.firstfloor.org> <c9e534200802051029u5d08cf6dm54866f769e362262@mail.gmail.com> <20080205200211.GA26150@one.firstfloor.org> <20080205203911.GA9891@2ka.mipt.ru> <20080205212017.5db50114@core>
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Hi Alan.

On Tue, Feb 05, 2008 at 09:20:17PM +0000, Alan Cox (alan@lxorguk.ukuu.org.uk) wrote:
> > Most (if not all) distributions have them enabled and window growing
> > works just fine. Actually I do not see any reason why connection
> > establishment handshake should prevent any run-time operations at all,
> > even if it was setup during handshake.
> 
> Syncookies are only triggered if the system is under a load where it
> would begin to lose connections otherwise. So they merely turn a DoS into
> a working if slightly slower setup (and > 64K windows don't matter for
> most normal users, especially on mobile devices).

SACK is actually a good idea for mobile devices, so preventing
syncookies from not getting into account some options (btw, does it work
with timestamps and PAWS?) is not a solution.

-- 
	Evgeniy Polyakov
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