Iptables: prevent spoofing with multiple internal nets?
I want to prevent spoofing in my iptables config. However, I am confused about how to go about it when using multiple internal nets. For instance:
So, to do anti-spoofing I have to put a line like:
iptables -A FORWARD -i eth1 -s ! (NET_1 OR NET_2) -j DROP
Obviously the above line won't work in iptables, but you see what I am trying to accomplish. Can anyone help me out?