YPXFR(8)						       NIS Reference Manual							  YPXFR(8)

NAME

       ypxfr - transfer NIS database from remote server to local host

SYNOPSIS

       /usr/lib/yp/ypxfr [-f] [-c] [-d target domain] [-h source host] [-s source domain] [-C taskid program-number ipaddr port] [-p yp_path]
			 mapname...

DESCRIPTION

       ypxfr copies an NIS database from one NIS server to the local host by using the NIS service.  ypxfr is generally invoked by ypinit or by
       ypserv, when ypserv receives a map transfer request from yppush.  It creates a temporary map in the directory /var/yp/domain (this
       directory must already exist; domain is the default domainname for the local host), fills it by getting the map's entries and fetches the
       map parameters (master and order number). If the transfer was successful, the old version of the map will be deleted and the temporary copy
       will be moved into its place. Then, ypxfr will attempt to send a "clear current map" request to the local ypserv.

       If run interactively, ypxfr writes its output to stderr. However, if it is invoked without a controlling terminal, it will log the output
       to syslog.

       ypxfr is used primarily in environments where several NIS servers are in use. For all maps, you have a NIS master server, which maintains a
       canonical copy of the NIS map, and all the other servers, the NIS slaves, copy the new version of the map from the master whenever a update
       was made. Normally, you have one NIS master for all maps.

       In order to maintain consistency across all NIS servers, ypxfr can be run periodically in a cron job. Maps which change infrequently need
       only be updated once a day (preferably late at night when system usage is lowest), where those with frequent changes (such as passwd.byname
       and passwd.byuid ) should be updated perhaps once every hour. Examples are in /usr/lib/yp: ypxfr_1perday, ypxfr_2perday, and
       ypxfr_1perhour.	They can serve as reasonable first cuts.

       Normally all updates should be propagated by yppush when /var/yp/Makefile is run on the NIS master server, however it is a good practice on
       large networks where possible outages could cause NIS slaves to fall out of sync with the master.

OPTIONS

       The following options are supported:

       -f
	   Force a map transfer. Normally, ypxfr will not transfer a map if it determines that the NIS master's copy is not newer than the
	   existing copy already on the local host. This flag forces a transfer regardless of which server's version is more recent.

       -c
	   Do not send a "clear current map" request to the ypserv process running on the local host. This flag is normally used when invoking
	   ypxfr by ypinit or if ypserv is not running locally at the time you are running ypxfr.  Otherwise, ypxfr will complain that it cannot
	   talk to the local ypserv, and the transfer will fail.

       -d domain
	   Specify a domain other than the default NIS domain.

       -h source host
	   Get the map from host, regardless of what the map says the master is. If host is not specified, ypxfr asks the NIS service for the name
	   of the master, and tries to get the map from there. This option is used to insure that ypxfr only copies maps from the NIS master
	   server.

       -s source domain
	   Specify a source domain from which to transfer a map that should be the same across domains.

       -C taskid progam-number ipaddr port
	   This option is only for use by ypserv .  When ypserv invokes ypxfr, it specifies that ypxfr should call back a yppush process at the
	   host with IP address ipaddr, registered as program number progam-number, listening on port port, and waiting for a response to
	   transaction taskid.

       -p yp_path
	   Change the directory for the maps to yp_path/[domainname]/, the default is /var/yp/[domainname].

       mapname
	   One or more names of the map to transfer.

FILES

       /var/yp/[domainname]/[maps]

SEE ALSO

       ypserv(8), yppush(8), ypinit(8), cron(8), crontab(5)

AUTHOR

       Thorsten Kukuk <kukuk@linux-nis.org>

NIS Reference Manual						    04/02/2009								  YPXFR(8)