Quelques exemples en attendant une vraie doc'...

(!) Voir aussi [[Etude/IPv6/Logiciels]]

(!) Voir aussi http://www.dns6.org/ pour un DNS dynamique gratuit pour IPv6 ! On ne devrait pas en avoir besoin en IPv6, mais quand on fait du 6to4 et que l'adresse IPv4 est dynamique, bah…

''Note : cette page doit être mise à jour avec la dernière version de ces fichiers !!''

== Liaison 6to4 automatique sur liaison dynamique ==
{i} Ceci est la configuration mise en place au CNF de Đà Nẵng.

 * Fichier `/etc/init.d/6to4` (à rendre exécutable) :
 {{{
#! /bin/sh
#
# 6to4	Script to configure a 6to4 "tunnel" device
#
#		Written by Daniel Lawson <daniel@meta.net.nz>

PATH=/sbin:/bin:/usr/sbin:/usr/bin

test -f $DAEMON || exit 0

# Source configuration file
. /etc/default/6to4

start_6to4_tunnel() {
  # GET EXTIF IP Address
  PPPIP=`ip -4 addr list $EXTIF | grep inet | awk '{ print $2'}`
  # From IanKumlien:
  # If you get a /netmask-bits suffix, then change the PPPIP line to:
  # PPPIP=`ip -4 addr list $EXTIF | grep inet | awk '{ print $2 }' | cut -d/ -f1`
  echo $PPPIP 
  # Set up the tunnel
  ip tunnel add ${IF} mode sit remote any local $PPPIP ttl 255
  ip link set dev ${IF} mtu 1472 up
}

start_routes() {
  # Route outgoing 6to4 via the tunnel
  ip -6 route add 2002::/16 dev ${IF}
  # If this is your only IPv6 connection, add some more routes as well:
  if [ ${ONLYCONN} == "yes" ]; then
    # This line seems necessary, but I've never found documented 
    # anywhere. Try without if you can.
    ip -6 route add ::/96 dev ${IF} metric 1 
    # Add a route toe the 6to4 Anycast address?
    ip -6 route add 2000::/3 via ::${GWADDR} dev tun6to4 metric 1
  fi
}
 
start_local_network() {
  # Add a 6to4 Address to ${INTIF}
  if [ -n ${INTIF} ]; then
    ip -6 addr add $(printf "2002:%02x%02x:%02x%02x::1/64" $(echo ${PPPIP} | tr '.' ' ')) dev ${INTIF}
  fi
}

stop_local_network() {
  if [ -n ${INTIF} ]; then
    # GET the *old* tunnel ip
    OLDIP=`ip -6 addr list dev ${IF} | grep inet6 | cut -d ":" -f 3 | cut -d '/' -f 1`
    # Remove the route via ${INTIF}
    ip -6 route del $(printf "2002:%02x%02x:%02x%02x::/64" $(echo ${OLDIP} | tr '.' ' ')) dev ${INTIF}
    # Remove the 6to4 IP assigned to ${INTIF}
    ip -6 addr del $(printf "2002:%02x%02x:%02x%02x::1/64" $(echo ${OLDIP} | tr '.' ' ')) dev ${INTIF}
  fi
}

stop_routes() {
  ip -6 route del 2002::/16 dev ${IF}
  if [ ${ONLYCONN} == "yes" ]; then
    ip -6 route del ::/96 dev ${IF} metric 1
    ip -6 route del 2000::/3 via ::${GWADDR} dev ${IF} metric 1
  fi
}

stop_6to4_tunnel() {
  ip -6 route flush dev ${IF}
  ip link set dev ${IF} down
	ip tunnel del ${IF} 
}

restart_6to4_ad () {
  [ "yes" == "${RADVD}" ] &&
  killall -1 radvd
}

case "$1" in
  start)
	echo -n "Setting up 6to4 IPv6 tunnel ($IF): "
	start_6to4_tunnel
	start_routes
	start_local_network
	restart_6to4_ad
	;;
  stop)
	echo -n "Shutting down 6to4 IPv6 tunnel ($IF): "
	stop_local_network
	stop_routes
	stop_6to4_tunnel
	restart_6to4_ad
	;;
  restart|force-reload)
	echo -n "Resetting 6to4 IPv6 tunnel ($IF): "
	stop_local_network
	stop_routes
	stop_6to4_tunnel
	start_6to4_tunnel
	start_routes
	start_local_network
	restart_6to4_ad
	;;
  *)
	echo "Usage: $0 {start|stop|restart|force-reload}" >&2
	exit 1
	;;
esac

exit 0
}}}

 * Fichier `/etc/default/6to4` :
 {{{
# Defaults for 6to4 initscript
# sourced by /etc/init.d/6to4
# installed at /etc/default/6to4 by the maintainer scripts

#
# This is a POSIX shell fragment
#

# What is the name of your tunnel interface?
IF=tun6to4

# What is the name of your external (real-world) interface?
EXTIF=ppp0

# What is the name of your internal (rfc1918) interface?
# If you do not wish to use this feature, then leave this blank. 
# If your internal hosts have real-world addresses themselves, then this
# set of scripts currently wont help you.
INTIF=eth1

# Do you use radvd for dynamic IPv6 addressing within your network?
RADVD=yes

# IS this your only IPv6 connection? If you have a freenet6, or some other 
# form of IPv6 connection, then set the following to no. If you are sure
# that this is your only IPv6 connection, set it to yes.
ONLYCONN=yes

# If this is your only IPv6 connection, you need a gateway to forward
# your 6to4 packets onto the 6bone. You should find a gateway that is
# as close to you as possible!
# Helsinki or somewhere similar
GWADDR=192.88.99.1
# AARNET in australia
#GWADDR=192.231.212.5

}}}

 * Fichier `/etc/ppp/ip-up.d/ipv6-6to4-up` (à rendre exécutable) :
 {{{
#!/bin/sh
/etc/init.d/6to4 stop
/etc/init.d/6to4 start
}}}

 * Fichier `/etc/ppp/ip-down.d/ipv6-6to4-down` (à rendre exécutable) :
 {{{
#!/bin/sh
/etc/init.d/6to4 stop
}}}

 * Fichier `/etc/radvd.conf` :
 {{{
interface eth1
{
        AdvSendAdvert on;
        # IgnoreIfMissing on;
        MinRtrAdvInterval 30;
        MaxRtrAdvInterval 60;
        AdvDefaultPreference high;
        AdvHomeAgentFlag off;

        prefix fec0::/64
        {
        };
#       prefix 3ffe:...:1::/64
#       {
#       };

        prefix 0:0:0:0::/64
        {
                AdvOnLink on;
                AdvAutonomous on;
                AdvRouterAddr off;
                Base6to4Interface ppp0;
                AdvPreferredLifetime 30;
                AdvValidLifetime 60;
        };
};
}}}

== Liaison 6to4 « à la main » ==
{i} Ceci est la configuration mise en place au BAP.

* Extrait du fichier `/etc/network/interfaces` :
 {{{
auto tun6to4
iface tun6to4 inet6 v4tunnel
        address 2002:d2f5:3dce:feed::1
        netmask 64
        endpoint any
        local 210.245.61.206
        ttl 64
        up ip -6 route add 2000::/3 via ::192.88.99.1 dev tun6to4
        up sysctl -w net.ipv6.conf.all.forwarding=1
        up sysctl -w net.ipv6.conf.all.autoconf=0
        up sysctl -w net.ipv6.conf.all.accept_ra=0
        up sysctl -w net.ipv6.conf.all.accept_redirects=0
        up sysctl -w net.ipv6.conf.all.router_solicitations=0
        down ip -6 route flush dev tun6to4
}}}
On remarquera que la partie 6to4 de l'adresse IPv6 (`d2f5:3dce`) correspond à l'adresse IPv4 locale (`210.245.61.206`). C'est impératif si on veut que les réponses reviennent vers cette adresse IPv4.

Pour calculer l'adresse IPv6 on peut utiliser la commande suivante qui se trouve dans le paquet éponyme : {{{
$ ipv6calc -I ipv4addr -O ipv6addr -A conv6to4 210.245.61.206
2002:d2f5:3dce::
}}}