NAME

       rpc.ypxfrd - NIS map transfer server

SYNOPSIS

       /usr/sbin/rpc.ypxfrd [ -d path ] [ -p port ] [ --debug ]
       /usr/sbin/rpc.ypxfrd --version

DESCRIPTION

       rpc.ypxfrd  is  used for speed up the transfer of very large NIS maps from a NIS master to
       the NIS slave server. If a  NIS slave server receives a message that there is a  new  map,
       it  will  start  ypxfr for transfering the new map.  ypxfr will read the contents of a map
       from the master server using the yp_all() function. This process can take several  minutes
       when there are very large maps which have to be stored by the database library.

       The  rpc.ypxfrd  server  speeds  up  the transfer process by allowing NIS slave servers to
       simply copy the master server's map files rather than building  their  own  from  scratch.
       rpc.ypxfrd uses an RPC-based file transfer protocol, so that there is no need for building
       a new map.

       rpc.ypxfrd could be started by inetd. But since  it  starts  very  slowly,  it  should  be
       started after ypserv from /etc/init.d/ypxfrd.

OPTIONS

       --debug
              Causes  the  server  to  run  in debugging mode. In debug mode, the server does not
              background itself and prints extra status messages to stderr for each request  that
              it revceives.

       -d directory
              rpc.ypxfrd is using this directory instead of /var/yp

       -p port
              rpc.ypxfrd  will bind itself to this port, which makes it possible to have a router
              filter packets to the NIS ports. This can restricted the access to the  NIS  server
              from hosts on the Internet.

       --version
              Prints the version number

SECURITY

       rpc.ypxfrd  uses  the  same functions for checking a host as ypserv.  At first, rpc.ypxfrd
       will check a request from an address with /etc/ypserv.securenets.  If the host is  allowed
       to  connect  to  the server, rpc.ypxfrd will uses the rules from /etc/ypserv.conf to check
       the requested map. If a mapname doesn't  match  a  rule,  rpc.ypxfrd  will  look  for  the
       YP_SECURE  key in the map. If it exists, rpc.ypxfrd will only allow requests on a reserved
       port.

FILES

       /etc/ypserv.conf /var/yp/securenets

SEE ALSO

       ypserv(8), makedbm(8), yppush(8), ypxfr(8)

BUGS

       The FreeBSD ypxfrd protocol is not compatible with that used by SunOS. This is unfortunate
       but  unavoidable:  Sun's  protocol  is  not freely available, and even if it were it would
       probably not be useful since the SunOS  NIS  v2  implimentation  uses  the  original  ndbm
       package  for  its  map databases whereas the other implimentation uses GNU DBM or Berkeley
       DB. These packages uses vastly different file formats.  Furthermore,  ndbm  and  gdbm  are
       byte-order  sensitive  and  not  very smart about it, meaning that a gdbm or ndbm database
       created on a big endian system can't be read on a little endian system. The FreeBSD ypxfrd
       protocol  checks,  if  both,  master  and  slave,  uses the same database packages and, if
       necessary, the byte order of the system.

AUTHOR

       ypxfrd protocol and FreeBSD Implementation: Bill Paul <wpaul@ctr.columbia.edu>
       Linux Implementation: Thorsten Kukuk <kukuk@suse.de>