Modern operating systems allows us to receive packets from an input interface, different
from the output interface.
In Linux, we can implement asymmetric routing using iptables (linux 2.4):
iptables –A POSTROUTING –t nat –j SNAT –to 192.168.0.5 –o eth0
This means, for all the packets going out via eth0, their source IP address will be
changed to 192.168.0.5. We also have to „disable“ reverse path filtering:
echo “0” > /proc/sys/net/ipv4/conf/all/rp_filter