IN.RDISC(1M)IN.RDISC(1M)NAME
in.rdisc, rdisc - network router discovery daemon
SYNOPSIS
/usr/sbin/in.rdisc [-a] [-f] [-s] [send-address] [receive-address]
/usr/sbin/in.rdisc -r [-p preference] [-T interval]
[send-address] [receive-address]
DESCRIPTIONin.rdisc remains part of the software distribution of the Solaris Oper‐
ating Environment. It is, however, not used by default. in.routed(1M)
includes the functionality provided by in.rdisc. See routeadm(1M) for
details of how to specify the IPV4 routing daemon.
in.rdisc implements the ICMP router discovery protocol. The first form
of the command is used on hosts and the second form is used on routers.
in.rdisc can be invoked in either the first form (host mode) or second
form (router mode).
On a host, in.rdisc populates the network routing tables with default
routes. On a router, advertises the router to all the hosts.
in.rdisc is managed by the service management facility (SMF), by means
of the service identifier:
svc:/network/routing/rdisc:default
Host (First Form)
On a host, in.rdisc listens on the ALL_HOSTS (224.0.0.1) multicast
address for ROUTER_ADVERTISE messages from routers. The received mes‐
sages are handled by first ignoring those listed router addresses with
which the host does not share a network. Among the remaining addresses,
the ones with the highest preference are selected as default routers
and a default route is entered in the kernel routing table for each one
of them.
Optionally, in.rdisc can avoid waiting for routers to announce them‐
selves by sending out a few ROUTER_SOLICITATION messages to the
ALL_ROUTERS (224.0.0.2) multicast address when it is started.
A timer is associated with each router address. The address will no
longer be considered for inclusion in the routing tables if the timer
expires before a new advertise message is received from the router. The
address will also be excluded from consideration if the host receives
an advertise message with the preference being maximally negative or
with a lifetime of zero.
Router (Second Form)
When in.rdisc is started on a router, it uses the SIOCGIFCONF ioctl(2)
to find the interfaces configured into the system and it starts listen‐
ing on the ALL_ROUTERS multicast address on all the interfaces that
support multicast. It sends out advertise messages to the ALL_HOSTS
multicast address advertising all its IP addresses. A few initial
advertise messages are sent out during the first 30 seconds and after
that it will transmit advertise messages approximately every 600 sec‐
onds.
When in.rdisc receives a solicitation message, it sends an advertise
message to the host that sent the solicitation message.
When in.rdisc is terminated by a signal, it sends out an advertise mes‐
sage with the preference being maximally negative.
OPTIONS
Supported options and equivalent SMF service properties are listed
below. SMF service properties are set using a command of the form:
# routeadm -m rdisc:default key=value
-a
Accept all routers independent of the preference they
have in their advertise messages. Normally, in.rdisc
only accepts (and enters in the kernel routing tables)
the router or routers with the highest preference.
Use of this option is equivalent to setting the
accept_all property to true.
-f
Run in.rdisc forever even if no routers are found.
Normally, in.rdisc gives up if it has not received any
advertise message after soliciting three times, in
which case it exits with a non-zero exit code. If -f
is not specified in the first form then -s must be
specified. For SMF execution, this option is
required.
-r
Act as a router, rather than a host. Use of this
option is equivalent to setting the act_as_router
property to true.
-s
Send three solicitation messages initially to quickly
discover the routers when the system is booted. When
-s is specified, in.rdisc exits with a non-zero exit
code if it can not find any routers. This can be over‐
ridden with the -f option. This option is not compati‐
ble with SMF execution and is not supported for the
rdisc service.
-p preference
Set the preference transmitted in the solicitation
messages. The default is zero. Use of this option is
equivalent to setting the preference property.
-T interval
Set the interval between transmitting the advertise
messages. The default time is 600 seconds. Use of this
option is equivalent to setting the transmit_interval
property.
The send-address and receive-address daemon options can be set by
means of the send_address and receive_address properties.
SEE ALSOin.routed(1M), routeadm(1M), svcadm(1M), ioctl(2), gateways(4),
attributes(5), smf(5), icmp(7P), inet(7P)
Deering, S.E., editor, ICMP Router Discovery Messages, RFC 1256, Net‐
work Information Center, SRI International, Menlo Park, California,
September 1991.
Nov 9, 2006 IN.RDISC(1M)
