From mboxrd@z Thu Jan  1 00:00:00 1970
From: Philip Craig <philipc@snapgear.com>
Subject: Re: many one-to-one NAT
Date: Mon, 17 May 2004 16:09:55 +1000
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To: Yaron Presente <ypresente@mrv.com>
Cc: netfilter@lists.netfilter.org

Yaron Presente wrote:
> I would like to do NAT from a private range to a public range of the 
> same size, in a way that just
> the network part of the IP address would be translated.

Use the NETMAP target.  This is included in 2.6, but I think you have to
patch 2.4 kernels still.

> For example, I would like a single iptables rule to map 192.168.10.0/24 
> => 10.1.1.0/24 as follows:
> 192.168.10.1 => 10.1.1.1
> 192.168.10.2 => 10.1.1.2
> .
> .
> .
> 192.168.10.254 => 10.1.1.254

Assuming 192.168.10.0/24 is private:

iptables -t nat -A PREROUTING -d 10.1.1.0/24 -j NETMAP --to 192.168.10.0/24
iptables -t nat -A POSTROUTING -s 192.168.10.0/24 -j NETMAP --to 10.1.1.0/24

-- 
Philip Craig - SnapGear, A CyberGuard Company - http://www.SnapGear.com