21.4.1.1. Simple configuration
Radvd's config file is normally /etc/radvd.conf. An simple example looks like following:
interface eth0 {
AdvSendAdvert on;
MinRtrAdvInterval 3;
MaxRtrAdvInterval 10;
prefix 2001:0db8:0100:f101::/64 {
AdvOnLink on;
AdvAutonomous on;
AdvRouterAddr on;
};
}; |
This results on client side in
# ip -6 addr show eth0
3: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
inet6 2001:0db8:100:f101:2e0:12ff:fe34:1234/64 scope global dynamic
valid_lft 2591992sec preferred_lft 604792sec
inet6 fe80::2e0:12ff:fe34:1234/10 scope link |
Because no lifetime was defined, a very high value was used.
21.4.1.2. Special 6to4 configuration
Version since 0.6.2pl3 support the automatic (re)-generation of the prefix depending on an IPv4 address of a specified interface. This can be used to distribute advertisements in a LAN after the 6to4 tunneling has changed. Mostly used behind a dynamic dial-on-demand Linux router. Because of the sure shorter lifetime of such prefix (after each dial-up, another prefix is valid), the lifetime configured to minimal values:
interface eth0 {
AdvSendAdvert on;
MinRtrAdvInterval 3;
MaxRtrAdvInterval 10;
prefix 0:0:0:f101::/64 {
AdvOnLink off;
AdvAutonomous on;
AdvRouterAddr on;
Base6to4Interface ppp0;
AdvPreferredLifetime 20;
AdvValidLifetime 30;
};
}; |
This results on client side in (assuming, ppp0 has currently 1.2.3.4 as local IPv4 address):
# /sbin/ip -6 addr show eth0
3: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
inet6 2002:0102:0304:f101:2e0:12ff:fe34:1234/64 scope global dynamic
valid_lft 22sec preferred_lft 12sec
inet6 fe80::2e0:12ff:fe34:1234/10 scope link |
Because a small lifetime was defined, such prefix will be thrown away quickly, if no related advertisement was received.
Additional note: if you do not used special 6to4 support in initscripts, you have to setup a special route on the internal interface on the router, otherwise you will get some backrouting problems. for the example showh here:
# /sbin/ip -6 route add 2002:0102:0304:f101::/64 dev eth0 metric 1 |
This route needs to be replaced every time the prefix changes, which is the case after a new IPv4 address was assigned to the dial-up interface.
