Hi! On 09:56 Thu 15 May , Varun Sharma wrote:

Hi All,

I am sending packet between two back to back connected machine.when I use same network (192.168.7.x) packet reach upto NF_IP_LOCAL_IN (IPTABLES INPUT) hook.It is accepted.

But when I spoof ip address network(192.168.8.x) it pass NF_IP_PRE_ROUTING hook but dropped before NF_IP_LOCAL_IN hook.

case 1:

192.168.7.12 --> 192.168.7.19 Accepted.

case 2:

192.168.8.25 --> 192.168.7.19 Dropped.

I didn't get why it dropped ? How network change effect on routing inside kernel tcp/ip stack ?

Maybe you have "Reverse Path Filtering" turned on: http://lartc.org/howto/lartc.kernel.html Try setting /proc/sys/net/ipv4/conf/*/rp_filter to "0". -Michi -- programing a layer 3+4 network protocol for mesh networks see http://michaelblizek.twilightparadox.com