How to isolate two lans on linux from each other?

Question

linux

There are two network cards in linux based on the clearos distribution, each with its own network interface, both are lan.
Out of the box, clearos routes all lan interfaces to each other, but I need to make lan isolated from each other.
How? Not necessarily by means of clearos, console commands will also work.

Answer 1

iptables -I FORWARD -i eth0 -o eth1 -j DROP
iptables -I FORWARD -i eth1 -o eth0 -j DROP

Notice the "-I" (insert) instead of "-A" (append).

Answer 2

Try this: xmodulo.com/2012/03/how-to-enable-ip-forwarding-in...

Answer 3

Method number 1. Fast.
Cut with iptables.
Look away iptables -A FORWARD (FORWARD chain)
Kill any traffic entering eth0 and leaving eth1.
to be sure, add the reverse sequence
Divide the network into VLANs (802.1q), but this is a long time, it can’t be explained in a nutshell.
Very well described here:
https://wiki.debian.org/NetworkConfiguration?highl...