NAME

     irdpd - internet router discovery protocol daemon


SYNOPSIS

     irdpd [-bd] [-U udp-device]  [-I  ip-device]  [-o  priority-
     offset]


DESCRIPTION

     Irdpd looks for routers.  This should be a simple task,  but
     some  routers are hard to find because they do not implement
     the router discovery protocol.  This daemon collects  infor-
     mation that routers do send out and makes it available.

     At startup  irdpd  sends  out  several  router  solicitation
     broadcasts.   A  good  router  should respond to this with a
     router advertisement.

     If a router advertisement arrives then no more solicitations
     are  sent.   The  TCP/IP server has filled its routing table
     with the info from the advertisement, so it now has at least
     one  router.   If  the  advertisement  is  sent by a genuine
     router (the sender is in the table) then  the  irdpd  daemon
     goes dormant for the time the advert is valid.  Routers send
     new adverts periodically, keeping the daemon silent.

     Otherwise irdpd will listen for RIP (Router Information Pro-
     tocol)  packets.   These packets are sent between routers to
     exchange routing information.  Irdpd uses  this  information
     to build a routing table.

     Every now and then a router advertisement  is  sent  to  the
     local  host to give it router information build from the RIP
     packets.


OPTIONS

     -b   Broadcast advertisements instead of sending them to the
          local  host only.  This may be used to keep (non-Minix)
          hosts alive on a net without adverts.

     -d   Debug mode, tell where info is coming from and where it
          is sent.  Debugging can also be turned on at runtime by
          sending signal SIGUSR1 or turned off with SIGUSR2.

     -o priority-offset
          Offset used to make the gateway's preferences collected
          from RIP packets look worse than those found in genuine
          router adverts.  By default -1024.


SEE ALSO

     inet(8), boot(8), dhcpd(8), inetd(8), nonamed(8).



BUGS

     This daemon has gone out of favour  thanks  to  dhcpd,  that
     also does router solicitations among other things.

     Under standard MINIX 3 this daemon can't listen to both IRDP
     and  RIP  at  the same time, so it starts out with IRDP.  It
     switches over to RIP if it can't find a  router,  or  if  it
     threatens to lose its router.  It does not switch back.


AUTHOR

     Kees J. Bot (kjb@cs.vu.nl)