Re: Re[2]: PREROUTING

[Alistair Tonner <Alistair@nerdnet.ca>]

On April 29, 2003 08:53 am, netfilter_user wrote:
> Hello SaVaGE,
>
> Tuesday, April 29, 2003, 9:49:10 AM, you wrote:
>
> S> Op dinsdag 29 april 2003 09:23, schreef netfilter_user:
> >> Hello everyone,
> >>
> >> this is my problem:
> >> My LAN is connected to Internet via Linux machine with 2 interface (
> >> ppp0 - for internet and eth1 for local net). I need to connect from
> >> local host, service that is running on port 23073 and 23083 UDP in
> >> internet. For this i wrote afew rules with PREROUTING but when I start
> >> script with rules below i receive:
> >>
> >> Bad argument `PREROUTING'
> >> Try `iptables -h' or 'iptables --help' for more information.
> >> Bad argument `PREROUTING'
> >> Try `iptables -h' or 'iptables --help' for more information.
> >>
> >>
> >> iptables -t nat -A PREROUTING -p udp -d 80.50.60.185 --dport 23073 -j
> >> DNAT --to-destination 192.168.1.2 iptables -t nat -A PREROUTING -p udp
> >> -d 80.50.60.185 --dport 23083 -j DNAT --to-destination 192.168.1.2
> >>
> >> iptables -A FORWARD -p udp -d 192.168.1.2 --dport 23073 -j ACCEPT
> >> iptables -A FORWARD -p udp -d 192.168.1.2 --dport 23083 -j ACCEPT
> >>
> >> What maybe a reason of this msg?
> >> Im using slackware 8.1 with iptables 1.2.6a
>
> S> This behaviour is correct NATting is done on the POSTROUTING table !!!!
>
>
> S> Pascal (PC-Secure Dutch security service)
>
> ammm....im afraid its not correct because I have received msg like this:
>
>  Bad argument `PREROUTING'
>  Try `iptables -h' or 'iptables --help' for more information.
>  Bad argument `PREROUTING'
>  Try `iptables -h' or 'iptables --help' for more information.
>
> ...its not correct in my newbe opinion.



	Actually DNAT is acceptable in the PREROUTING chain.
	change the --to-destination option to 
  	--to ip.ad.dr.ess:portnum
	or 
	--to ip.ad.dre.ss
	
-- 

	Alistair Tonner
	nerdnet.ca
	Senior Systems Analyst - RSS
	
     Any sufficiently advanced technology will have the appearance of magic.
	Lets get magical!