You need "iptables-dev", "dkms" and "linux-headers". For a DKMS
template, see https://wiki.kubuntu.org/Kernel/Dev/DKMSPackaging

Note: svn propedit svn:ignore .

Note: on ubuntu, you need to enable prefer-family in /etc/wgetrc.
after this e.g. "wget -O /dev/null http://ftp.se.debian.org" should
connect to the IPv6 addrs of that server.

/etc/gai.conf

for wget --prefer-family=IPv6 -O - http://6to4.nro.net/
ip6tables -t mangle -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

Mention --nocheck for speedup (if you do not expect the outer iface in the mapping range)