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 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  adver-
     tise 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 multi-
     cast  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 approxi-
     mately 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 nega-
     tive.

OPTIONS
     -a              Accept  all  routers  independent   of   the
                     preference they have in their advertise mes-
                     sages. Normally, in.rdisc only accepts  (and
                     enters  in  the  kernel  routing tables) the
                     router or routers with the  highest  prefer-
                     ence.



     -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  soli-
                     citation 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  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWroute                   |
    |_____________________________|_____________________________|


SEE ALSO
     in.routed(1M), routeadm(1M), ioctl(2),  gateways(4),  attri-
     butes(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.