command to get the appropriate kernel sources installed:
apt-get source linux-image-$(uname -r)
configure screen resolution and more
especially, note the comment about "blacklist ipv6" in /etc/modules.d/blacklist. That finally disabled it. (yeah!)
Althought this document is old by computing standars, the simple routing policy example allowed me to do in 2 hours what I failed to do in two years of working with OpenBSD. Don't know if that's a reflection on me or OBSD.