Prefixes

Basic prefix options

Prefixes are defined in [prefix_<prefix>] sections. “<prefix>” is just an identifier and can be whatever you want. In this example “client_local” is arbitrarily chosen as type for the address:

[prefix_client_local]

Prefixes at the moment only can have one  sensible category:

  • range – generate prefix of given ranges

Every prefix definition therefore needs an category option and a pattern option for its automatic generation. The dynamic part of the prefix is represented by a placeholder referring to the category and enclosed by $:

category = range
pattern = 2001:db8::$range$

A range need an extra option range that defines it. Ranges can range from 0-FFFF and contrary to ranges in addresses need to be part of the network definition. In this example ranges range from 2001:db8:1000::/64 to 2001:db8:1fff::/64.

[prefix_client]
category = range
range = 1000-1fff
pattern = 2001:db8:$range$:

The default prefix length is 64 but can be adjusted too by the length option. With a given length of 48 the prefixes will range from 2001:db8:2000::/48 to 2001:db8:3fff::/48.

[prefix_client]
category = range
range = 2000-4fff
pattern = 2001:db8:$range$:
length = 48

Additional options for prefixes

Addresses can have these additional options:

  • preferred_lifetime
  • valid_lifetime

Prefixes will per default have the lifetimes set by general settings, but preferred_lifetime and valid_lifetime can be modified:

preferred_lifetime = 900
valid_lifetime = 1200

If the routing to the delegated prefix should be done via the Link Local Address of the requesting host, the option route_link_lokal must be set.

route_link_local = yes