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From: "krv" <krv@kaevee.com>
To: netfilter@lists.netfilter.org
Subject: Re: Synfloods - SNAT slow down
Date: Fri, 23 Apr 2004 20:25:07 +0530	[thread overview]
Message-ID: <00c601c42942$f7b919e0$2800a8c0@jupiter> (raw)
In-Reply-To: 005f01c42940$79a18210$1202a8c0@admin

----- Original Message -----
From: "Rob Sterenborg" <rob@sterenborg.info>
To: <netfilter@lists.netfilter.org>
Sent: Friday, April 23, 2004 8:07 PM
Subject: Re: Synfloods - SNAT slow down


> > I have two thousand hosts and two thousand forward rules :(
>
> With so many hosts/rules you should be able to match subnets instead of
> each host separately, reducing the number of rules greatly which in turn
> improves Netfilter performance. Or do you have a special reason to do
> this ?
>
>
> Gr,
> Rob
>

I had seen a patch in patch-o-matic which is supposed to fix a performance
issue in SNAT during floods. In fact the current kernel runs with the above
said patch.

You are right. In fact, I am rewriting the script which will generate
netfilter rules. I wanted to find out whether I can fine tune the new
netfilter rule set to offset the overloading of the gateway due to syn/icmp
floods.

Do you think, if I have a hierarchical filter rule set, there would be an
improvement?

KRV





      reply	other threads:[~2004-04-23 14:55 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-04-23  1:23 Synfloods - SNAT slow down krv
2004-04-23  7:01 ` David Cannings
2004-04-23 13:43   ` krv
2004-04-23 14:37     ` Rob Sterenborg
2004-04-23 14:55       ` krv [this message]

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