On Thu, 2005-01-06 at 08:23, Igor Tsinman wrote: > Mario Ohnewald wrote: > >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=21,2121 > > > > > >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 > > > > > > > You have to add an additional rule: > $IPT -A FORWARD -p tcp -i eth1 -d 23.123.123.123 --dport 2121 -j ACCEPT > > For this example, eth0 is external and eth1 is internal. I only have one network card. Cheers, Mario
