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In a wireless Ad-Hoc network, I have two computers which communicates in UDP together from to

I have a third computer ( which wants to listen to the packets which are not addressed to it. I can see the packets with tcpdump (which sets the wireless card in promiscuous mode).

To redirect the packets, I am using :

iptables -t nat -I PREROUTING -s -j DNAT --to-destination

Is it the only rule I need to use? Why isn't it working? Did I miss other requirements?

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You are asking about sniffing packets, yet you want to forward them ? What are you trying to do ? – BatchyX Jun 17 '13 at 20:18

Maybe you just need to instruct the machine that it should reach the .5 machine over the .6 machine (depending on the route command syntax insert gw between the IP addresses):

route add

...and on the .6 machine ip forwarding needs to be enabled, which can be done by echo 1 > /proc/sys/net/ipv4/ip_forward (note the space after the 1).

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