rarpd - reverse address resolution protocol daemon

     rarpd [-d]

     Rarpd listens on the ethernet for broadcast packets  asking  for  reverse
     address resolution.  These packets are sent by hosts at boot time to find
     out their IP address.  Rarpd looks up the six octet  ethernet  number  in
     the /etc/ethers file finding a host name.  This name is translated to the
     IP address of the host by a DNS lookup.  The IP address is then  sent  to
     the host.

     Before rarpd can start its  service  it  first  finds  out  what  the  IP
     addresses  of the ethernets are.  It will look through /etc/ethers to map
     the ethernet addresses to host names.  It then uses /etc/hosts to map the
     host  names  to  IP  addresses.   If  this lookup fails then several RARP
     requests are broadcasted in the hope that  some  RARP  server  knows  the
     addresses.   The  IP  addresses  are  eventually  set  in the same way as
     ifconfig(8).  (The address is not changed if already set with  ifconfig.)
     Note  that  the  host  names  in  the  ethers  and hosts files must match
     exactly.  The DNS can not  be  used  yet,  so  a  simple  name  can't  be
     translated to a fully qualified name.

     Once the addresses are configured rarpd  will  figure  out  the  netmasks
     associated  by these addresses.  It will do this by repeatedly looking up
     the netmask corresponding to an interfaces' network  address:  ip-address
     AND  current-netmask.   Once  the  netmask  stops  changing  the  network
     interface is configured with this netmask.  Suppose for example that  the
     address  for an interface is  The initial netmask for this
     class B address is  So we look  up  the  netmask  associated
     with  (  &   This  lookup  yields, so now  look  up  to  find
     Lastly  we  look up to find again so we use
     it to set the netmask.

     If rarpd determines that the machine has no real ethernet connection then
     it  will  configure  the default network to have IP address with

     Rarpd exits after startup if there are no active ethernets, or  if  there
     is no ethers file.

     Warning! Sun diskless workstations assume that the first RARP server that
     answers  is  the  host they are to boot from.  For this to work all other
     Sun RARP servers delay their answer if they are not also  the  requestors
     boot  server.   The  Minix  rarpd  does  not  have this kludge so it will
     happily engage the Sun boot server to  see  who  can  answer  the  client
     first.   Unless your Minix host can actually serve a Sun diskless client,
     it is better not  to  list  any  more  hosts  in  the  ethers  file  than


     -d   Turns on debugging messages.  Debugging can also  be  turned  on  at
          runtime by sending signal SIGUSR1 or turned off with SIGUSR2.

     ifconfig(8),  ethers(5),  hosts(5),  netdefault(8),  boot(8),   inetd(8),
     irdpd(8), nonamed(8).

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