Re: How to Forward a port (DNAT) ?

[Antony Stone <Antony@Soft-Solutions.co.uk>]

On Saturday 10 July 2004 10:39 pm, Frédéric Gonzatti wrote:

> My iptables rules are :
> ##########################################"
> iptables -F
> iptables -X
>
> echo 1 > /proc/sys/net/ipv4/ip_forward
>
> iptables -P INPUT DROP
> iptables -P FORWARD DROP
> iptables -P OUTPUT DROP
>
> iptables -t filter -A INPUT -i lo -j ACCEPT
> iptables -t filter -A OUTPUT -o lo -j ACCEPT
>
> iptables -t nat -A PREROUTING -p tcp --dport 25 -i eth2 -j DNAT --to
> 192.168.2.151:25
>
> #################################################"
>
> It's a very simple test. But unfortunately it doesn't work.

You need a FORWARD rule to allow the packets through the firewall after being 
DNATted - you also need to allow the reply packets.

iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -p tcp --dport 25 -d 192.168.2.251 -j ACCEPT

I recommend Oskar Andreasson's tutorial http://iptables-tutorial.frozentux.net 
to you.

Regards,

Antony.

-- 
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