.\"	$NetBSD: rtadvd.conf.5,v 1.20 2018/04/21 09:31:08 wiz Exp $
.\"	$KAME: rtadvd.conf.5,v 1.50 2005/01/14 05:30:59 jinmei Exp $
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.Dd April 20, 2018
.Dt RTADVD.CONF 5
.Os
.Sh NAME
.Nm rtadvd.conf
.Nd config file for router advertisement daemon
.Sh DESCRIPTION
This file describes how the router advertisement packets must be constructed
for each of the interfaces.
.Pp
As described in
.Xr rtadvd 8 ,
you do not have to set this configuration file up at all,
unless you need some special configurations.
You may even omit the file as a whole.
In such cases, the
.Nm rtadvd
daemon will automatically configure itself using default values
specified in the specification.
.Pp
It obeys the famous
.Xr capfile 5
file format.
Each line in the file describes a network interface.
Fields are separated by a colon
.Pq Sq \&: ,
and each field contains one capability description.
Lines may be concatenated by the
.Sq \e
character.
The comment marker is the
.Sq \&#
character.
.Sh CAPABILITIES
Capabilities describe the value to be filled into ICMPv6 router
advertisement messages and to control
.Xr rtadvd 8
behavior.
Therefore, you are encouraged to read IETF neighbor discovery documents
if you would like to modify the sample configuration file.
.Pp
Note that almost all items have default values.
If you omit an item, the default value of the item will be used.
.Pp
There are two items which control the interval of sending router advertisements.
These items can be omitted, then
.Nm rtadvd
will use the default values.
.Bl -tag -width indent
.It Cm \&maxinterval
(num) The maximum time allowed between sending unsolicited
multicast router advertisements
.Pq unit: seconds .
The default value is 600.
Its value must be no less than 4 seconds
and no greater than 65535 seconds.
.It Cm \&mininterval
(num) The minimum time allowed between sending unsolicited multicast
router advertisements
.Pq unit: seconds .
The default value is the one third of value of
.Cm maxinterval .
Its value must be no less than 3 seconds and no greater than .75 *
the value of
.Cm maxinterval .
.El
.Pp
The following items are for ICMPv6 router advertisement message
header.
These items can be omitted, then
.Nm rtadvd
will use the default values.
.Bl -tag -width indent
.It Cm \&chlim
(num) The value for Cur Hop Limit field.
The default value is 64.
.It Cm \&raflags
(str or num) A 8-bit flags field in router advertisement message header.
This field can be specified either as a case-sensitive string or as an
integer.
A sting consists of characters each of which corresponds to a
particular flag bit(s).
An integer should be the logical OR of all enabled bits.
Bit 7
.Po
.Li 'm' or 0x80
.Pc
means Managed address configuration flag bit,
and Bit 6
.Po
.Li 'o' or 0x40
.Pc
means Other stateful configuration flag bit.
Bit 4
.Po
.Li 0x10
.Pc
and Bit 3
.Po
.Li 0x08
.Pc
are used to encode router preference.
Bits 01
.Po
or 'h'
.Pc
means high, 00 means medium, and 11
.Po
or 'l'
.Pc
means low.
Bits 10 is reserved, and must not be specified.
There is no character to specify the medium preference explicitly.
The default value of the entire flag is 0
(or a null string),
which means no additional
configuration methods, and the medium router preference.
.It Cm \&rltime
(num) Router lifetime field
.Pq unit: seconds .
The value must be either zero or between
the value of
.Cm maxinterval
and 65535.
When
.Nm rtadvd
runs on a host, this value must explicitly set 0 on all the
advertising interfaces as described in
.Xr rtadvd 8 .
The default value is 1800.
.It Cm \&rtime
(num) Reachable time field
.Pq unit: milliseconds .
The default value is 0, which means unspecified by this router.
.It Cm \&retrans
(num) Retrans Timer field
.Pq unit: milliseconds .
The default value is 0, which means unspecified by this router.
.El
.Pp
The following items are for ICMPv6 prefix information option,
which will be attached to router advertisement header.
These items can be omitted, then
.Nm rtadvd
will automatically get appropriate prefixes from the kernel's routing table,
and advertise the prefixes with the default parameters, unless the
.Cm noifprefix
flag is specified.
Keywords other than
.Cm clockskew
and
.Cm noifprefix
can be augmented with a number, like
.Dq Li prefix2 ,
to specify multiple prefixes.
.Bl -tag -width indent
.It Cm \&noifprefix
(bool) Specified whether
.Nm rtadvd
should gather prefix information from the interface if no
.Cm addr
is specified.
If no
.Cm addr
is given, and
.Cm noifprefix
is set,
.Nm rtadvd
will send RA packets with no prefix information.
.It Cm \&clockskew
(num) Time skew to adjust link propagation delays and clock skews
between routers on the link
.Pq unit: seconds .
This value is used in consistency check for locally-configured and
advertised prefix lifetimes, and has its meaning when the local router
configures a prefix on the link with a lifetime that decrements in
real time.
If the value is 0, it means the consistency check will be skipped
for such prefixes.
The default value is 0.
.It Cm \&prefixlen
(num) Prefix length field.
The default value is 64.
.It Cm \&pinfoflags
(str or num) A 8-bit flags field in prefix information option.
This field can be specified either as a case-sensitive string or as an
integer.
A sting consists of characters each of which corresponds to a
particular flag bit(s).
An integer should be the logical OR of all enabled bits.
Bit 7
.Po
.Li 'l' or 0x80
.Pc
means On-link flag bit,
and Bit 6
.Po
.Li 'a' or 0x40
.Pc
means Autonomous address-configuration flag bit.
The default value is "la" or 0xc0, i.e., both bits are set.
.It Cm \&addr
(str) The address filled into Prefix field.
Since
.Dq \&:
is used for
.Xr capfile 5
file format as well as IPv6 numeric address, the field MUST be quoted by
doublequote character.
.It Cm \&vltime
(num) Valid lifetime field
.Pq unit: seconds .
The default value is 2592000 (30 days).
.It Cm \&vltimedecr
(bool) This item means the advertised valid lifetime will decrement
in real time, which is disabled by default.
.It Cm \&pltime
(num) Preferred lifetime field
.Pq unit: seconds .
The default value is 604800 (7 days).
.It Cm \&pltimedecr
(bool) This item means the advertised preferred lifetime will decrement
in real time, which is disabled by default.
.El
.Pp
The following item is for ICMPv6 MTU option,
which will be attached to router advertisement header.
This item can be omitted, then
.Nm rtadvd
will use the default value.
.Bl -tag -width indent
.It Cm \&mtu
(num or str) MTU (maximum transmission unit) field.
If 0 is specified, it means that the option will not be included.
The default value is 0.
If the special string
.Dq auto
is specified for this item, MTU option will be included and its value
will be set to the interface MTU automatically.
.El
.Pp
The following item controls ICMPv6 source link-layer address option,
which will be attached to router advertisement header.
As noted above, you can just omit the item, then
.Nm rtadvd
will use the default value.
.Bl -tag -width indent
.It Cm \&nolladdr
(bool) By default
.Po
if
.Cm \&nolladdr
is not specified
.Pc ,
.Xr rtadvd 8
will try to get link-layer address for the interface from the kernel,
and attach that in source link-layer address option.
If this capability exists,
.Xr rtadvd 8
will not attach source link-layer address option to
router advertisement packets.
.El
.Pp
The following items are for ICMPv6 route information option,
which will be attached to router advertisement header.
These items are optional.
Each items can be augmented with number, like
.Dq Li rtplen2 ,
to specify multiple routes.
.Bl -tag -width indent
.It Cm \&rtprefix
(str) The prefix filled into the Prefix field of route information option.
Since
.Dq \&:
is used for
.Xr capfile 5
file format as well as IPv6 numeric address, the field MUST be quoted by
doublequote character.
.It Cm \&rtplen
(num) Prefix length field in route information option.
The default value is 64.
.It Cm \&rtflags
(str or num) A 8-bit flags field in route information option.
Currently only the preference values are defined.
The notation is same as that of the raflags field.
Bit 4
.Po
.Li 0x10
.Pc
and Bit 3
.Po
.Li 0x08
.Pc
are used to encode the route preference for the route.
The default value is 0x00, i.e. medium preference.
.It Cm \&rtltime
(num) route lifetime field in route information option.
.Pq unit: seconds .
Since the specification does not define the default value of this
item, the value for this item should be specified by hand.
However,
.Nm rtadvd
allows this item to be unspecified, and uses the router lifetime
as the default value in such a case, just for compatibility with an
old version of the program.
.El
.Pp
In the above list, each keyword beginning with
.Dq Li rt
could be replaced with the one beginning with
.Dq Li rtr
for backward compatibility reason.
For example,
.Cm rtrplen
is accepted instead of
.Cm rtplen .
However, keywords that start with
.Dq Li rtr
have basically been obsoleted, and should not be used any more.
.Pp
The following items are for ICMPv6 Recursive DNS Server Option and
DNS Search List Option
.Pq RFC 6106 ,
which will be attached to router advertisement header.
These items are optional.
.Bl -tag -width indent
.It Cm \&rdnss
(str) The IPv6 address of one or more recursive DNS servers.
The argument must be inside double quotes.
Multiple DNS servers can be specified in a comma-separated string.
If different lifetimes are needed for different servers,
separate entries can be given by using
.Cm rdnss ,
.Cm rdnss0 ,
.Cm rdnss1 ,
.Cm rdnss2 ...
options with corresponding
.Cm rdnssltime ,
.Cm rdnssltime0 ,
.Cm rdnssltime1 ,
.Cm rdnssltime2 ...
entries.
Note that the maximum number of servers depends on the receiver side.
See also the
.Xr resolv.conf 5
manual page for the resolver implementation.
.It Cm \&rdnssltime
The lifetime of the
.Cm rdnss
DNS server entries.
The default value is 3/2 of the interval time.
.It Cm \&dnssl
(str) One or more domain names in a comma-separated string.
These domain names will be used when making DNS queries on a
non-fully-qualified domain name.
If different lifetimes are needed for different domains, separate entries
can be given by using
.Cm dnssl ,
.Cm dnssl0 ,
.Cm dnssl1 ,
.Cm dnssl2 ...
options with corresponding
.Cm dnsslltime ,
.Cm dnsslltime0 ,
.Cm dnsslltime1 ,
.Cm dnsslltime2 ...
entries.
Note that the maximum number of names depends on the receiver side.
See also the
.Xr resolv.conf 5
manual page for the resolver implementation.
.It Cm \&dnsslltime
The lifetime of the
.Cm dnssl
DNS search list entries.
The default value is 3/2 of the interval time.
.El
.Pp
You can also refer one line from another by using
.Cm tc
capability.
See
.Xr capfile 5
for details on the capability.
.Sh EXAMPLES
As presented above, all of the advertised parameters have default values
defined in specifications, and hence you usually do not have to set them
by hand, unless you need special non-default values.
It can cause interoperability problem if you use an ill-configured
parameter.
.Pp
To override a configuration parameter, you can specify the parameter alone.
With the following configuration,
.Xr rtadvd 8
overrides the router lifetime parameter for the
.Li ne0
interface.
.Bd -literal
ne0:\\
	:rltime#0:
.Ed
.Pp
The following example manually configures prefixes advertised from the
.Li ef0
interface.
The configuration must be used with the
.Fl s
option to
.Xr rtadvd 8 .
.Bd -literal
ef0:\\
	:addr="2001:db8:ffff:1000::":prefixlen#64:
.Ed
.Pp
The following example configures the
.Li wlan0
interface and adds two DNS servers and a DNS domain search options
using the default option lifetime values.
.Bd -literal -offset 8n
wlan0:\\
	:addr="2001:db8:ffff:1000::":prefixlen#64:\\
	:rdnss="2001:db8:ffff::10,2001:db8:ffff::2:43":\\
	:dnssl="example.com":
.Ed
.Pp
The following example presents the default values in an explicit manner.
The configuration is provided just for reference purposes;
YOU DO NOT NEED TO HAVE IT AT ALL.
.Bd -literal
default:\\
	:chlim#64:raflags#0:rltime#1800:rtime#0:retrans#0:\\
	:pinfoflags="la":vltime#2592000:pltime#604800:mtu#0:
ef0:\\
	:addr="2001:db8:ffff:1000::":prefixlen#64:tc=default:
.Ed
.Sh SEE ALSO
.Xr capfile 5 ,
.Xr rtadvd 8 ,
.Xr rtsol 8
.Pp
Thomas Narten, Erik Nordmark and W. A. Simpson,
.Do
Neighbor Discovery for IP version 6 (IPv6)
.Dc ,
RFC 2461
.Pp
Richard Draves,
.Do
Default Router Preferences and More-Specific Routes
.Dc ,
RFC 4191
.Pp
J. Jeong, S. Park, L. Beloeil, S. Madanapalli
.Do
IPv6 Router Advertisement Options for DNS Configuration
.Dc ,
RFC 6106
.Sh HISTORY
The
.Xr rtadvd 8
and the configuration file
.Nm
first appeared in WIDE Hydrangea IPv6 protocol stack kit.
.\" .Sh BUGS
.\" (to be written)