netdev - Re: [PATCH] route: add more relaxed option for secure

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Date:	Wed, 16 Nov 2011 21:17:38 -0200
From:	Flavio Leitner <fbl@...hat.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH] route: add more relaxed option for secure_redirects

On Wed, 16 Nov 2011 17:02:13 -0500 (EST)
David Miller <davem@...emloft.net> wrote:

> From: Flavio Leitner <fbl@...hat.com>
> Date: Wed, 16 Nov 2011 18:46:12 -0200
> 
> > Thus, the only option at the sender side would be using iptables
> > to change the ICMP redirect source address to be the float address,
> > but that is not working as well. (It isn't passing through -t nat)
> 
> If it's going to mangle the packet in one direct, the only option
> for sane operation is to make the exact reverse transformation in
> the other direction for ICMP messages.
> 
> I'm sorry to be so difficult about this, but this is the only way to
> handle this problem.  If packet mangling is performed to change the
> world, that mangling entity has taken on the responsibility to make
> everything look correct to all entities for the mangled packets
> and any packets generated in response to such mangled packets.
>

I'm sorry, I lost you there. There is no transformation happening in
any side. The iptables is just a work around to force the outgoing
ICMP redirect to use the correct source address (secondary or alias). 

The whole problem is the linux gateway sending ICMP redirects using
*always* the primary address.

fbl
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