focal (8) ypxfr.8.gz
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@suse.de>