I made some assumptions about other rules you would have had in place. I believe someone else posted a much more thorough answer. Did you create an ESTABLISHED,RELATED rule as that other post suggested? Would you mind posting your complete rule set (with any sensitive information edited, of course)? - John On Tue, 2005-09-27 at 08:30 -0700, Alaios wrote: > Thx for your quick reply..... i have just tested but > it didnt work... I think that i cant explain what i > need or i am doing sth wrong.. > i have enabled the packets loging > so executing dmesg prints the following > IN=eth1 OUT= MAC=(the mac addresses) > As u can see the OUT is null which means thats perhaps > the problem... What do u have in mind? > > --- "John A. Sullivan III" > <jsullivan@xxxxxxxxxxxxxxxxxxx> wrote: > > > On Tue, 2005-09-27 at 11:14 -0400, John A. Sullivan > > III wrote: > > > On Tue, 2005-09-27 at 07:57 -0700, Alaios wrote: > > > > Hi plz take a look at the following example > > > > > > > > The laptop has 2 ethernet interfaces > > > > To eth1 comes traffic from src 143.233.222.253 > > > > The eth0 has ip address 10.2.4.2 and it is > > connected > > > > back to back with eth1 of other pc with ip > > address > > > > 10.2.4.1 > > > > I want to forward the traffic with src > > 143.233.222.253 > > > > to the 10.2.4.1 pc and if it works i will redo > > this > > > > for a second pc so as to l send the traffic to a > > third > > > > on. > > > > Can u help me plz? > > > > > > > > I have tried this one > > > > iptables -t nat -A PREROUTING -i eth1 -s > > > > 143.233.222.253 -j DNAT --to-destination > > 10.2.4.1 > > > > i have also set the > > > > /proc/sys/net/ipv4/ip_forward to 1 > > > > but still i cant see any trafiic to eth0 > > interface (ip > > > > 10.2.4.2) > > > > > > > > > > > > I have also tested this one > > > > iptables -t nat -A PREROUTING -p tcp -d > > 143.233.222.77 > > > > (laptop eth1 card) --dport 22453 (i have cheched > > dst > > > > port with tcpdump) 00 -j DNAT --to-destination > > > > 10.2.4.1 > > > > this still doesnt work > > > > Every time i try to apply a new rule i use first > > > > the iptables -F > > > > iptables -t nat -F command > > > <snip> > > > > > > I'm a little confused about what you are doing. I > > would normally refer > > > you to Oskar Andreasson's excellent tutorial at > > > > > > http://iptables-tutorial.frozentux.net/iptables-tutorial.html > > or the > > > training slides on the ISCS web site > > (http://iscs.sourceforge.net) but, > > > since it appears that you have an emergency, here > > goes: > > > > > > First, if the source is 143.233.222.253, you would > > not want to DNAT it. > > > DNAT changes the destination. Thus, your second > > attempt is the correct > > > one. You might want to lock the destination port > > - it's not likely to > > > be a problem but, if it ever is, it will be one of > > those really hard to > > > diagnose, sporadic problems: > > > -j DNAT --to-destination 10.2.4.1:22453 > > > > > > Second, this only takes care of the addressing. > > You must still allow > > > the traffic in the FORWARD chain of the filter > > table, e.g., > > > > > > iptables -A FORWARD -d 10.2.4.1 -p 6 --dport 22453 > > -j ACCEPT > > > > > > Hope this helps - John > > > > Oh, yes, you wanted to restrict the source address. > > Add that to your > > filter table rule: > > iptables -A FORWARD -s 143.233.222.253 -d 10.2.4.1 > > -p 6 --dport 22453 -j > > ACCEPT > > -- > > John A. Sullivan III > > Open Source Development Corporation > > +1 207-985-7880 > > jsullivan@xxxxxxxxxxxxxxxxxxx > > > > If you would like to participate in the development > > of an open source > > enterprise class network security management system, > > please visit > > http://iscs.sourceforge.net > > > > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com -- John A. Sullivan III Open Source Development Corporation +1 207-985-7880 jsullivan@xxxxxxxxxxxxxxxxxxx Financially sustainable open source development http://www.opensourcedevel.com
