From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Mario Ohnewald" Subject: NAT FROM public ip TO public ip Date: Fri, 7 Jan 2005 05:36:48 +0100 (MET) Message-ID: <10459.1105072608@www72.gmx.net> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: netfilter-bounces@lists.netfilter.org Errors-To: netfilter-bounces@lists.netfilter.org Content-Type: text/plain; charset="iso-8859-1" To: netfilter@lists.netfilter.org Hello List! This is a real easy question, but i will explain it in detail so that you know what i am on about ;) I have two internet boxes, both have only one nic. Box A is my root box. Box B is a ftp server (where i am not admin, but i have an ftp account). Both, Box A and B have a public ip address. You can NOT access the ftp server from the outside. ONLY Box A can connect to that ftp server (Box B). So i though i could simply nat a connection through my Box A, to Box B. If i connect from the real bad world, to my Box A, port 2121. Box A could forward/NAT that to the internal ftp box. I have tried it with this rule: $IPT -t nat -A PREROUTING -i eth0 -p tcp -d 123.123.123.123 -m helper --helper ftp-2121 -j DNAT --to-destination 123.123.123.111 and modprobe ip_conntrack_ftp ports=3D21,2121 But it looks like its not working. I did a tcpdump -i eth0 -n host 123.123.123.111 And no packages where transfered to the ftp box (123.123.123.111). Any idea why? Am i going the right way at all? Thanks, Mario --=20 +++ GMX - die erste Adresse f=FCr Mail, Message, More +++ 1 GB Mailbox bereits in GMX FreeMail http://www.gmx.net/de/go/mail