Date: Mon, 13 Sep 2004 06:18:47 +0200
From: Willy Tarreau <willy@w.ods.org>
To: Paul Jakma <paul@clubi.ie>
Cc: Toon van der Pas <toon@hout.vanvergehaald.nl>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Wolfpaw - Dale Corse <admin@wolfpaw.net>, kaukasoi@elektroni.ee.tut.fi,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Linux 2.4.27 SECURITY BUG - TCP Local and REMOTE(verified) Denial of Service Attack
Message-ID: <20040913041846.GD2780@alpha.home.local>
References: <002301c498ee$1e81d4c0$0200a8c0@wolf> <1095008692.11736.11.camel@localhost.localdomain> <20040912192331.GB8436@hout.vanvergehaald.nl> <Pine.LNX.4.61.0409130413460.23011@fogarty.jakma.org> <Pine.LNX.4.61.0409130425440.23011@fogarty.jakma.org>
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On Mon, Sep 13, 2004 at 04:30:36AM +0100, Paul Jakma wrote:
 
> More specifically, BGP should have treated TCP resets as a transient 
> error, to be expected (indeed, they /cant/ be a sign that a link is 
> down - if you can receive a RST the link or path is patently quite 
> ok).

The application level does not always distinguish between TCP RST and
error generated by the local system because of a "network unreachable"
due to a link down and a lost route.

> The BGP state machine should instead, in normal operation, have 
> only treated Hold time expired as the definitive sign of "peer is 
> down" and allowed reconnects.

It should not necessarily wait for the time-out, but at least wait for
a few reconnect errors.

Regards,
willy

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