демон обнаружения сетевого маршрутизатора (network router discovery daemon)
Имя (Name)
rdisc - network router discovery daemon
Синопсис (Synopsis)
rdisc [-abdfrstvV] [-p preference] [-T max_interval]
[send_address] [receive_address]
Описание (Description)
rdisc implements client side of the ICMP Internet Router
Discovery Protocol (IRDP). rdisc is invoked at boot time to
populate the network routing tables with default routes.
rdisc listens on the ALL_HOSTS (224.0.0.1) multicast address (or
receive_address if it is provided) 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, 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 (or send_address if
it is provided) when it is started.
A timer is associated with each router address and 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 received advertise message has a preference
of maximum negative.
Server side of router discovery protocol is supported by Cisco
IOS and by any more or less complete UNIX routing daemon, for
example gated. If compiled with ENABLE_RDISC_SERVER, rdisc can
act as responder.
Параметры (Options)
-a
Accept all routers independently of the preference they have
in their advertise messages. Normally rdisc only accepts (and
enters in the kernel routing tables) the router or routers
with the highest preference.
-b
Opposite to -a, i.e. install only router with the best
preference value. This is the default behaviour.
-d
Send debugging messages to syslog.
-f
Keep rdisc running in the background even if no routers are
found. Normally rdisc gives up if it has not received any
advertise message after soliciting three times. In this case
it exits with a non-zero exit code. If -f is not specified in
the first form then -s must be specified.
-r
Responder mode, available only if compiled with
ENABLE_RDISC_SERVER.
-s
Send three solicitation messages initially to quickly
discover the routers when the system is booted. When -s is
specified rdisc exits with a non-zero exit code if it can not
find any routers. This can be overridden with the -f option.
-p preference
Set preference in advertisement messages. Available only with
-r option.
-T max_interval
Set maximum advertisement interval in seconds. Default is
600. Available only with -r option.
-t
Test mode. Do not go to background.
-v
Be verbose and send lots of debugging messages to syslog.
-V
Print version and exit.
История (History)
This program was developed by Sun Microsystems (see copyright
notice in source file). It was ported to Linux by Alexey
Kuznetsov <kuznet@ms2.inr.ac.ru>.
Смотри также (See also)
icmp(7), inet(7), ping(8).
Безопасность (Security)
rdisc requires CAP_NET_RAW to listen and send ICMP messages and
capability CAP_NET_ADMIN to update routing tables.
Доступность (Availability)
rdisc is part of iputils package.
