Thanks for all your error reports, I didn't forget it. I'll cleanup my guide soon. Thanks again!
If several interfaces look into the same subnet, Linux will answer to all ARP requests with only one MAC address. To solve this:
net.ipv4.conf.all.arp_ignore=1 net.ipv4.conf.all.arp_announce=2
Ugh, seems that it does not actually work.
Learn Linux The Hard Way
