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From: Andi Kleen <ak@suse.de>
To: Tim Gardner <timg@tpi.com>
Cc: YOSHIFUJI Hideaki / ???????????? <yoshfuji@linux-ipv6.org>,
	pekkas@netcore.fi, laforge@gnumonks.org, netdev@oss.sgi.com
Subject: Re: [PATCH + RFC] neighbour/ARP cache scalability
Date: Tue, 21 Sep 2004 19:31:34 +0200	[thread overview]
Message-ID: <20040921173134.GC12132@wotan.suse.de> (raw)
In-Reply-To: <1095784761.3934.52.camel@tim.rtg.net>

> I've developed a variant of the Port Scan Detector (PSD) iptables filter
> that combats this very problem. It only allows so many destination
> IP/Port pairs from a given address to be opened over time. This limits
> the rate at which connections can be opened as well as the absolute
> number. For example, on my edge routers I set the policy that no single
> IP source address can create more then 64 connections within a 30 second
> sliding window. This has made a huge impact on the ARP storms that our
> network used to experience.

But also allows an easy DOS. Someone just has to spoof a lot of connections
attempts with the source address of your primary name server or 
some other important service.

-Andi

  reply	other threads:[~2004-09-21 17:31 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-20 22:51 [PATCH + RFC] neighbour/ARP cache scalability Harald Welte
2004-09-21  6:29 ` David S. Miller
2004-09-21  7:04 ` Andre Tomt
2004-09-21  7:37 ` Robert Olsson
2004-09-21  8:58 ` Andi Kleen
2004-09-21 11:19 ` Pekka Savola
2004-09-21 13:49   ` Harald Welte
2004-09-21 14:10     ` Pekka Savola
2004-09-21 15:14     ` YOSHIFUJI Hideaki / 吉藤英明
2004-09-21 15:36       ` Robert Olsson
2004-09-21 15:59         ` YOSHIFUJI Hideaki / 吉藤英明
2004-09-21 15:58       ` Pekka Savola
2004-09-21 16:04         ` YOSHIFUJI Hideaki / 吉藤英明
2004-09-21 16:39           ` Tim Gardner
2004-09-21 17:31             ` Andi Kleen [this message]
2004-09-21 17:58               ` Tim Gardner
2004-09-21 18:15                 ` Andi Kleen
2004-09-21 20:34                   ` Harald Welte
2004-09-21 20:58                     ` Tim Gardner
2004-09-22  1:14                       ` Harald Welte
2004-09-22  3:31 ` David S. Miller
2004-09-22 11:14   ` Harald Welte
2004-09-24  5:53     ` David S. Miller
2004-09-24  7:14     ` Glen Turner
2004-09-24  5:47   ` David S. Miller

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