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
