in.rdisc(1M)						  System Administration Commands					      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]

DESCRIPTION

       in.rdisc remains part of the software distribution of the Solaris Operating 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.

   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 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 lis-
       tening 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

       -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.

       -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.

       -r	       Act as a router, rather than a host.

       -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.

       -p preference   Set the preference transmitted in the solicitation messages. The default is zero.

       -T interval     Set the interval between transmitting the advertise messages. The default time is 600 seconds.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWroute 		   |
       +-----------------------------+-----------------------------+

SEE ALSO

       in.routed(1M), routeadm(1M), ioctl(2), gateways(4), attributes(5), icmp(7P), inet(7P)

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

SunOS 5.10							    5 Nov 2004							      in.rdisc(1M)