From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Vishwanatn T. K." <tkvishy@yahoo.com>
Subject: Re: FORWARD rules
Date: 11 Sep 2003 06:09:29 +0000
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To: Payal Rathod <payal-iptables@staticky.com>
Cc: netfilter@lists.netfilter.org

On Wed, 2003-09-10 at 17:52, Payal Rathod wrote:
> Hi,
> I had kept the default policy of FORWARD as drop.
> Now, I wanted to see an internal machine from internet. So, I used
> DNAT as,
> 
> iptables -A PREROUTING -t nat -d <ext ip> -j DNAT --to <int ip>
> It didn't work. When I set the default FORWARD policy to ACCEPT it
> worked.
> 
> What is a better approach? I want to have a default DROP in FORWARD
> chain. My FORWARD chain looked like this,
> 
> 
> $IPTABLES -A FORWARD -s 125.125.125.0/32 -p tcp -m tcp --dport 53 -j ACCEPT
> $IPTABLES -A FORWARD -s 125.125.125.0/32 -p udp -m tcp --dport 53 -j ACCEPT
> $IPTABLES -A FORWARD -s 125.125.125.0/32 -p tcp -m tcp --dport 80 -j ACCEPT
> $IPTABLES -A FORWARD -s 125.125.125.0/32 -p tcp -m tcp --dport 110 -j ACCEPT
> $IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
> 
> What more do I add to allow natting as well as a secure FORWARD policy?
> Is the position of ESTABLISHED rule ok?
> 

You need to add NEW state in the above FORWARD rule for this to work.

$IPTABLES -A FORWARD -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT

> Thanks a lot for the help in advance and waiting eagerly for the mails.
> With warm regards,
> -Payal

Vishwanath