From mboxrd@z Thu Jan  1 00:00:00 1970
From: Martijn Lievaart <m@rtij.nl>
Subject: Re: NAT on stateless firewall ?
Date: Fri, 03 Aug 2007 21:15:01 +0200
Message-ID: <46B37EB5.3060803@rtij.nl>
References: <46B26400.7050504@andrei.myip.org>	<46B2FB97.3090605@plouf.fr.eu.org>	<46B3729A.8030605@andrei.myip.org>
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Florin Andrei wrote:
> Florin Andrei wrote:
>> Grant Taylor wrote:
>>>
>>> Dare I ask why you are wanting to use Proxy ARP?
>>
>> Well, it's required by DNAT, isn't it?
>
> I take that back. I figured it out.
>
> I actually tested the idea yesterday, but it failed because one of the 
> test machines was not configured properly.
>
> To make proxy ARP work with DNAT, an IP alias must be created on the 
> external interface, with the public IP address of the machine behind 
> the firewall.
>
> ip address add XXX.YYY.ZZZ.KKK dev eth0
>
> where XXX.YYY... is the public IP address that corresponds to the 
> private IP address of a server behind the firewall.
>
> It's not even necessary to play with proxy_arp in /proc. Just the IP 
> alias and DNAT.
>


I think you could even get away with just creating a static arp entry.

M4