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

     The functionality provided by the  in.rdisc  daemon  is  now
     included  in  in.routed(1M).  in.rdisc  remains  part of the
     software distribution of the Solaris Operating  Environment.
     However,  the  system  startup  scripts in /etc/init.d start
     in.routed and do not start in.rdisc. If you want to  custom-
     ize  router  discovery  behavior,  consult  gateways(4). See
     in.routed(1M) for information on that 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 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 over-
           ridden 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  attri-
     butes:

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

SEE ALSO

     in.routed(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.