packet drop

[michi1 at michaelblizek.twilightparadox.com]

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