RPC.YPXFRD(8)           FreeBSD System Manager's Manual          RPC.YPXFRD(8)

NAME
     rpc.ypxfrd - NIS map transfer server

SYNOPSIS
     rpc.ypxfrd [-p path]

DESCRIPTION
     The rpc.ypxfrd utility is used to speed up the distribution of very large
     NIS maps from NIS master to NIS slave servers.  The normal method for
     transferring maps involves several steps:

           •   The master server calls yppush(8) to inform the slave servers
               to start a transfer.

           •   The slave servers invoke ypxfr(8), which reads the entire
               contents of a map from the master server using the yp_all()
               function.

           •   The ypxfr(8) program then creates a new map database file by
               using the db(3) library hash method to store the data that it
               receives from the server.

           •   When all the data has been retrieved, ypxfr(8) moves the new
               file into place and sends ypserv(8) on the local machine a
               YPPROC_CLEAR to tell it to refresh its database handles.

     This process can take several minutes when there are very large maps
     involved.  For example: a passwd database with several tens of thousands
     of entries can consume several megabytes of disk space, and it can take
     the db(3) library package a long time to sort and store all the records
     in a hash database.  Consider also that there are two sets of map files:
     master.passwd.by{name,uid} and passwd.by{name,uid}.

     The rpc.ypxfrd utility 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.  Simply put, rpc.ypxfrd implements an
     RPC-based file transfer protocol.  Transferring even a multi-megabyte
     file in this fashion takes only a few seconds compared to the several
     minutes it would take even a reasonably fast slave server to build a new
     map from scratch.

     The rpc.ypxfrd utility uses the same access restriction mechanism as
     ypserv(8).  This means that slave servers will only be permitted to
     transfer files if the rules in the securenets database permit it (see
     ypserv(8) for more information on securenets).  Furthermore, only slave
     servers using reserved ports will be allowed to transfer the
     master.passwd maps.

OPTIONS
     The following option is available:

     -p path
             This option can be used to override the default path to the
             location of the NIS map databases.  The compiled-in default path
             is /var/yp.

FILES
     /var/yp/[domainname]/[maps]       The NIS maps for a particular NIS
                                       domain.

SEE ALSO
     yp(8), yppush(8), ypserv(8), ypxfr(8)

AUTHORS
     Bill Paul <wpaul@ctr.columbia.edu>

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 implementation uses the original ndbm package for its map
     databases whereas the FreeBSD implementation uses Berkeley DB.  These two
     packages use vastly different file formats.  Furthermore, ndbm is byte-
     order sensitive and not very smart about it, meaning that am ndbm
     database created on a big endian system cannot be read on a little endian
     system.

FreeBSD 13.1-RELEASE-p6          June 2, 1996          FreeBSD 13.1-RELEASE-p6