YPXFR(8) System Manager's Manual YPXFR(8)
ypxfr - transfer NIS map from NIS server to here
/usr/etc/yp/ypxfr [ -b ] [ -c ] [ -f ] [ -d domain ]
[ -h host ] [ -s domain ] [ -C tid prog ipadd port ]
ypxfr moves a Network Information Service (NIS) map in the default
domain for the local host to the local host by making use of normal NIS
services. It creates a temporary map in the directory /var/yp/domain
(this directory must already exist; domain is the default domain for
the local host), fills it by enumerating the map's entries, fetches the
map parameters (master and order number), and loads them. It then
deletes any old versions of the map and moves the temporary map to the
If run interactively, ypxfr writes its output to the terminal. How-
ever, if it is invoked without a controlling terminal, and if the log
file /var/yp/ypxfr.log exists, it will append all its output to that
file. Since ypxfr is most often run from the super-user's crontab
file, or by ypserv, you can use the log file to retain a record of what
was attempted, and what the results were.
If issecure(3) is TRUE, ypxfr requires that ypserv on the host be run-
ning as root. If the map being transferred is a secure map, ypxfr sets
the permissions on the map to 0600.
For consistency between servers, ypxfr should be run periodically for
every map in the NIS data base. Different maps change at different
rates: the services.byname map may not change for months at a time, for
instance, and may therefore be checked only once a day (in the wee
hours). You may know that mail.aliases or hosts.byname changes several
times per day. In such a case, you may want to check hourly for
updates. A crontab(5) entry can be used to perform periodic updates
automatically. Rather than having a separate crontab entry for each
map, you can group commands to update several maps in a shell script.
Examples (mnemonically named) are in /usr/etc/yp: ypxfr_1perday,
ypxfr_2perday, and ypxfr_1perhour. They can serve as reasonable first
Refer to ypfiles(5) and ypserv(8) for an overview of the NIS service.
-b Preserve the resolver flag in the map during the transfer.
-c Do not send a "Clear current map" request to the local ypserv
process. Use this flag 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.
-f Force the transfer to occur even if the version at the master is
not more recent than the local version.
Specify a domain other than the default domain.
Get the map from host, regardless of what the map says the mas-
ter 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.
host may be a name or an internet address in the form a.b.c.d.
Specify a source domain from which to transfer a map that should
be the same across domains (such as the services.byname map).
-Ctid prog ipadd 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
prog, listening on port port, and waiting for a response to
/var/yp/ypxfr.log log file
script to run one transfer per day, for use with
script to run two transfers per day
script for hourly transfers of volatile maps
/var/yp/domain NIS domain
Super-user's crontab file
issecure(3), crontab(5), ypfiles(5), cron(8), ypserv(8), yppush(8),
YP Protocol Specification, in
The Network Information Service (NIS) was formerly known as Sun Yellow
Pages (YP). The functionality of the two remains the same; only the
name has changed. The name Yellow Pages is a registered trademark in
the United Kingdom of British Telecommunications plc, and may not be
used without permission.
21 December 1987 YPXFR(8)