Port Forwarding with iptables (sorry for first half post, sent by mistake)

Hi there,

I want to enable port forwarding (or NAT?) on my linux machine so that any
packets on a specified port from my ppp device are automatically forwarded
to a particluar machine.

I have tried the following but it doesnt work. Can someone tell me what I
need to do? Do I also need to add rules to the INPUT/OUTPUT list?

iptables -A PREROUTING -t nat -p tcp --dport 1111 -j DNAT --to
10.0.0.200:1111

Thanks
Allan

In article <bii5i8$7vu$1@news.freedom2surf.net>, Allan Bruce wrote:
> I have tried the following but it doesnt work. Can someone tell me what I
> need to do? Do I also need to add rules to the INPUT/OUTPUT list?

Close, but not quite. INPUT is for packets destined for the firewall
machine itself, and your DNAT rule changed the destination. FORWARD is
the chain you need:

iptables -I FORWARD -p tcp --dport 1111 -j ACCEPT

> iptables -A PREROUTING -t nat -p tcp --dport 1111 -j DNAT --to \
> 10.0.0.200:1111

I used -I to ensure it works no matter what. The order of rules is
important. You might not want to put it first in your rules, and it's
probably best to put it in a user chain rather than directly in FORWARD.
--
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> iptables -I FORWARD -p tcp --dport 1111 -j ACCEPT

Thanks, that has it working now :o)
Allan