Technical data

4. Packages
Important: If the subnet is connected to a tunnel (see IPV6_NET_x_TUNNEL below) then
only the part of the router address is specified here that is not assigned to the tunnel’s sub-
net prefix (to be found in IPV6_TUNNEL_x_PREFIX) because that prefix and the address are
combined! In previous versions of the IPv6 package the variable IPV6_TUNNEL_x_PREFIX
did not exist and subnet prefix and router address were combined together in IPV6_NET_x.
That does not work if the subnet prefix associated by the tunnel provider is first handed
out when instantiating the dynamic tunnel. In addition the length of the subnet prefix (in
this case /48) is not known and certain predefined routes can not be set properly. This
leads to strange effects while routing to some specific destinations. The configuration was
separated to avoid such effects.
Examples:
IPV6_NET_1='2001:db8:1743:42::1/64' # without tunnel: complete address
IPV6_NET_1_TUNNEL=''
IPV6_NET_2='0:0:0:42::1/64' # with tunnel: partial address
IPV6_NET_2_TUNNEL='1'
IPV6_TUNNEL_1_PREFIX='2001:db8:1743::/48' # see "Tunnel Configuration"
IPV6_NET_x_DEV This variable contains for a specific IPv6 subnet the name of the network
interface to which the IPv6 network is bound. This does not collide with the network
interfaces assigned in the base configuration (base.txt) because a network interface can
have both IPv4 and IPv6 addresses assigned.
Example: IPV6_NET_1_DEV='eth0'
IPV6_NET_x_TUNNEL This variable contains the index of the associated tunnel for a spe-
cific IPv6 subnet. The prefix of the tunnel is combined with the router address to get the
complete IPv6 address of the router. If the variable is empty or undefined then no tunnel
belongs to the subnet and in IPV6_NET_x the full IPv6 address of the router including
network mask has to be specified (see above).
A tunnel can be assigned to multiple subnets because a tunnel subnet is usually large
enough to be split in multiple subnets (/56 or greater). It is not possible to assign
multiple tunnel subnet prefixes to a subnet because the address of the subnet would be
ambiguous in this case.
Example: IPV6_NET_1_TUNNEL='1'
IPV6_NET_x_ADVERTISE This variable determines whether the chosen subnet prefix is
advertised on the LAN via “Router Advertisements”. This is used for the so-called
“Stateless auto-configuration” and should not be confused with DHCPv6. Possible values
are “yes” and “no”.
It is recommended to enable this setting, unless all addresses in the network are statically
assigned or another router is already responsible to advertise the subnet prefix.
Important: Automatic distribution of the subnet will only work if the subnet is a /64
network, i.e. if the length of the subnet prefix is 64 bits! The reason for this is that the
other hosts in the network compute their IPv6 address from the prefix and their host MAC
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