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>