IN.RDISC(8) Maintenance Commands and Procedures IN.RDISC(8)

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]

DESCRIPTION

in.rdisc remains part of the software distribution of the Solaris
Operating Environment. It is, however, not used by default.
in.routed(8) includes the functionality provided by in.rdisc. See
routeadm(8) 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
messages 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
themselves 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 listening 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 seconds.


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
message 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 overridden with the -f option. This
option is not compatible 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 ALSO

ioctl(2), icmp(4P), inet(4P), gateways(5), attributes(7), smf(7),
in.routed(8), routeadm(8), svcadm(8)


Deering, S.E., editor, ICMP Router Discovery Messages, RFC 1256,
Network Information Center, SRI International, Menlo Park,
California, September 1991.

November 9, 2006 IN.RDISC(8)