RDNSS and DNSSL documentation for RAdv.

basic information about a local network (e.g. a list of network

prefixes), which allows network hosts to autoconfigure network

addresses and choose a default route. BIRD implements router behavior

as defined in RFC 4861<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4861.txt">.

as defined in

RFC 4861<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4861.txt">

and also the DNS extensions from

RFC 6106<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc6106.txt">.

<sect1>Configuration

<p>There are two classes of definitions in RAdv configuration --

interface definitions and prefix definitions:

<p>There are several classes of definitions in RAdv configuration --

interface definitions, prefix definitions and DNS definitions:

<descrip>

	<tag>interface <m/pattern [, ...]/  { <m/options/ }</tag>

	detailed description.

	<tag>prefix <m/prefix/ { <m/options/ }</tag>

	Prefix definitions allows to modify a list of advertised

	Prefix definitions allow to modify a list of advertised

	prefixes. By default, the advertised prefixes are the same as

	the network prefixes assigned to the interface. For each

	network prefix, the matching prefix definition is found and

	definitions. As expected, the prefix definition is matching if

	the network prefix is a subnet of the prefix in prefix

	definition.

	<tag>rdnss { <m/options/ }</tag>

	RDNSS definitions allow to specify a list of advertised

	recursive DNS servers together with their options. As options

	are seldom necessary, there is also a short variant <cf>rdnss

	<m/address/</cf> that just specifies one DNS server. Multiple

	definitions are cumulative. RDNSS definitions may also be

	interface-specific when used inside interface options. By

	default, interface uses both global and interface-specific

	options, but that can be changed by <cf/rdnss local/ option.

	<tag>dnssl { <m/options/ }</tag>

	DNSSL definitions allow to specify a list of advertised DNS

	search domains together with their options. Like <cf/rdnss/

	above, multiple definitions are cumulative, they can be used

	also as interface-specific options and there is a short

	variant <cf>dnssl <m/domain/</cf> that just specifies one DNS

        search domain.

</descrip>

<p>Interface specific options:

	<tag>min ra interval <m/expr/</tag>

	This option specifies the minimum length of that intervals, in

	seconds. Must be at least 3 and at most 3/4 * max ra interval.

	Default: about 1/3 * max ra interval.

	seconds. Must be at least 3 and at most 3/4 * <cf/max ra interval/.

	Default: about 1/3 * <cf/max ra interval/.

	<tag>min delay <m/expr/</tag>

	The minimum delay between two consecutive router advertisements,

	This option specifies the time (in seconds) how long (after

	the receipt of RA) hosts may use the router as a default

	router. 0 means do not use as a default router. Default: 3 *

	max ra interval.

	<cf/max ra interval/.

	<tag>rdnss local <m/bool/</tag>

	Use only local (interface-specific) RDNSS definitions for this

	interface. Otherwise, both global and local definitions are

	used. Could also be used to disable RDNSS for given interface

	if no local definitons are specified. Default: no.

	<tag>dnssl local <m/bool/</tag>

	Use only local DNSSL definitions for this interface. See

	<cf/rdnss local/ option above. Default: no.

</descrip>

	14400 (4 hours)

</descrip>

<p>RDNSS specific options:

<descrip>

	<tag>ns <m/address/</tag>

	This option specifies one recursive DNS server. Can be used

	multiple times for multiple servers. It is mandatory to have

	at least one <cf/ns/ option in <cf/rdnss/ definition.

	<tag>lifetime [mult] <m/expr/</tag>

	This option specifies the time how long the RDNSS information

        may be used by clients after the receipt of RA. It is

        expressed either in seconds or (when <cf/mult/ is used) in

        multiples of <cf/max ra interval/. Note that RDNSS information

        is also invalidated when <cf/default lifetime/ expires. 0

        means these addresses are no longer valid DNS servers.

	Default: 3 * <cf/max ra interval/.

</descrip>

<p>DNSSL specific options:

<descrip>

	<tag>domain <m/address/</tag>

	This option specifies one DNS search domain. Can be used

	multiple times for multiple domains. It is mandatory to have

	at least one <cf/domain/ option in <cf/dnssl/ definition.

	<tag>lifetime [mult] <m/expr/</tag>

	This option specifies the time how long the DNSSL information

        may be used by clients after the receipt of RA. Details are

	the same as for RDNSS <cf/lifetime/ option above.

	Default: 3 * <cf/max ra interval/.

</descrip>

<sect1>Example

<p><code>