RTADVD.CONF(5) | File Formats Manual | RTADVD.CONF(5) |
rtadvd.conf
—
config file for router advertisement daemon
This file describes how the router advertisement packets must be constructed for each of the interfaces.
As described in 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 rtadvd
daemon will automatically
configure itself using default values specified in the specification.
It obeys the famous termcap(5) file format. Each line in the file describes a network interface. Fields are separated by a colon (‘:’), and each field contains one capability description. Lines may be concatenated by the ‘\’ character. The comment marker is the ‘#’ character.
Capabilities describe the value to be filled into ICMPv6 router advertisement messages and to control rtadvd(8) behavior. Therefore, you are encouraged to read IETF neighbor discovery documents if you would like to modify the sample configuration file.
Note that almost all items have default values. If you omit an item, the default value of the item will be used.
There are two items which control the interval of sending router
advertisements. These items can be omitted, then
rtadvd
will use the default values.
maxinterval
mininterval
maxinterval
. Its value must be no less
than 3 seconds and no greater than .75 * the value of
maxinterval
.The following items are for ICMPv6 router advertisement message
header. These items can be omitted, then rtadvd
will
use the default values.
chlim
raflags
'm' or 0x80
) means Managed address
configuration flag bit, and Bit 6 ('o' or 0x40
)
means Other stateful configuration flag bit. Bit 4
(0x10
) and Bit 3 (0x08
)
are used to encode router preference. Bits 01 (or 'h') means high, 00
means medium, and 11 (or 'l') 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.rltime
maxinterval
and 9000. When
rtadvd
runs on a host, this value must explicitly
set 0 on all the advertising interfaces as described in
rtadvd(8). The default value is
1800.rtime
retrans
The following items are for ICMPv6 prefix information option,
which will be attached to router advertisement header. These items can be
omitted, then rtadvd
will automatically get
appropriate prefixes from the kernel's routing table, and advertise the
prefixes with the default parameters. Keywords other than
clockskew
can be augmented with a number, like
“prefix2
”, to specify multiple
prefixes.
clockskew
prefixlen
pinfoflags
'l' or 0x80
) means On-link flag bit, and Bit 6
('a' or 0x40
) means Autonomous
address-configuration flag bit. The default value is "la" or
0xc0, i.e., both bits are set.addr
vltime
vltimedecr
pltime
pltimedecr
The following item is for ICMPv6 MTU option, which will be
attached to router advertisement header. This item can be omitted, then
rtadvd
will use the default value.
mtu
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 rtadvd
will
use the default value.
nolladdr
nolladdr
is not specified),
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,
rtadvd(8) will not attach source
link-layer address option to router advertisement packets.The following item controls ICMPv6 home agent information option, which was defined with mobile IPv6 support. It will be attached to router advertisement header just like other options do.
hapref
hatime
must be present as well.hatime
When mobile IPv6 support is turned on for
rtadvd(8), advertisement interval
option will be attached to router advertisement packet, by configuring
maxinterval
explicitly.
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
“rtplen2
”, to specify multiple
routes.
rtprefix
rtplen
rtflags
0x10
) and Bit 3
(0x08
) are used to encode the route preference for
the route. The default value is 0x00, i.e., medium preference.rtltime
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.In the above list, each keyword beginning with
“rt
” could be replaced with the one
beginning with “rtr
” for backward
compatibility reason. For example, rtrplen
is
accepted instead of rtplen
. However, keywords that
start with “rtr
” have basically been
obsoleted, and should not be used any more.
You can also refer one line from another by using
tc
capability. See
termcap(5) for details on the
capability.
The following items are for the ICMPv6 recursive DNS server (RDNSS) option, which will be attached to the router advertisement header.
rdnssaddrs
rdnssaddr
item below. Indices vary from 0 to
N-1, where N is the value of rdnssaddrs
. Each
index shall follow the name of rdnssaddr
, e.g.,
“rdnssaddr0”.rdnssaddr
rdnssaddrs
is more than 0.rdnsslifetime
maxinterval
, which is
also the maximum value that should be set. The minimum value is
maxinterval
. If you specify a value outside of
this range, a message is logged.The following items are for the ICMPv6 DNS search list (DNSSL) option, which will be attached to the router advertisement header.
dnssldomains
dnssldomain
item below. Indices vary from
0 to N-1, where N is the value of dnssldomains
.
Each index shall follow the name of dnssldomain
,
e.g., “dnssldomain0”.dnssldomain
dnssldomains
is more than 0.dnssllifetime
maxinterval
, which is
also the maximum value that should be set. The minimum value is
maxinterval
. If you specify a value outside of
this range, a message is logged.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.
To override a configuration parameter, you can specify the
parameter alone. With the following configuration,
rtadvd(8) overrides the router lifetime
parameter for the ne0
interface.
ne0:\ :rltime#0:
The following example manually configures prefixes advertised from
the ef0
interface. The configuration must be used
with the -s
option to
rtadvd(8).
ef0:\ :addr="3ffe:501:ffff:1000::":prefixlen#64:
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.
default:\ :chlim#64:raflags#0:rltime#1800:rtime#0:retrans#0:\ :pinfoflags="la":vltime#2592000:pltime#604800:mtu#0: ef0:\ :addr="3ffe:501:ffff:1000::":prefixlen#64:tc=default:
Thomas Narten, Erik Nordmark, and W. A. Simpson, Neighbor Discovery for IP version 6 (IPv6), RFC 2461.
Richard Draves, Default Router Preferences and More-Specific Routes, draft-ietf-ipngwg-router-selection-xx.txt.
J. Jeong, S. Park, L. Beloeil, and S. Madanapalli, IPv6 Router Advertisement Option for DNS Configuration, RFC 5006.
The rtadvd(8) and the
configuration file rtadvd.conf
first appeared in
WIDE Hydrangea IPv6 protocol stack kit.
February 24, 2012 | macOS 14.6 |