Without binding netfilter rules with interfaces it will not work, and you'll get the results you allready got.
Catalin Borcea wrote:
Hello,
I tried to mark the packets in the PREROUTING chain but still doesn't work.
Now the packets are no marked anymore when they go out by the eth2
interface. When I marked them in the OUTPUT chain they arrived also to the
eth2 interface but marked. According to the docs the PREROUTING chain is not
traversed by locally generated packets so, I don't know how this works for
you. Maybe you have forwarded packets and not locally generated packets.