NAME

SYNOPSIS

DESCRIPTION

When run, ypxfr creates a temporary database file in /var/yp/[domainname], and fills it with the contents of mapname as supplied by the specified source host. When the entire map has been transferred, ypxfr deletes the original copy of mapname and moves the temporary copy into its place. When the transfer is complete, ypxfr will attempt to send a 'clear current map' request to the local ypserv(8) process to clear any possible references it may still have to the stale map.

Note that all files created by ypxfr are owner readable and writable only for security reasons. Since the NIS maps and the directory in which they reside are normally owned by root, this prevents non-privileged users from making unauthorized modifications.

In order to maintain consistency across all NIS servers, ypxfr can be run periodically in a cron(8) job. Maps which change infrequently need only be updated once a day (preferably late at night when system usage is lowest), whereas those that are subject to frequent changes (such a passwd.byname and passwd.byuid) should be updated perhaps once every hour. Using cron(8) to automatically update the NIS maps is not strictly mandatory since all updates should be propagated by yppush(8) when /var/yp/Makefile is run on the NIS master server, however it is good practice on large networks where possible outages could cause NIS servers to fall out of sync with each other.

When ypxfr is invoked without a controlling terminal, e.g. from inside ypserv(8), it logs all its output using the syslog(3) facility.

NOTES

Note that while the FreeBSD ypxfrd protocol is conceptually similar to the SunOS ypxfrd protocol, the FreeBSD protocol is not compatible with Sun's, therefore it will not work with Sun's ypxfrd server. FreeBSD slave systems can still transfer maps from any non-FreeBSD NIS server, however they will only be able to take advantage of the faster protocol if the master server is also running FreeBSD.

OPTIONS

-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: the -f 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(8) process running on the local host. This flag is normally used when invoking ypxfr manually on a machine that is not yet running ypserv(8). Without this flag, failure to contact the local NIS server will cause ypxfr to abort the transfer.

-d target domain

Specify a target domain other than the current NIS domain.

-h source host

Specify the name of the host from which to copy the NIS maps. This option is used to ensure that ypxfr only copies maps from the NIS master server.

-s source domain

Specify the domain from which to transfer a map, in the event that the transfer is being done across two different NIS domains.

-p path

Specify the top level directory containing the NIS maps. By default, this path is /var/yp. The -p flag allows you to specify an alternate path should you wish to store your NIS maps in a different part of the file system. The NIS server, ypserv(8), passes this flag to ypxfr if it too has been told to use an alternate path.

-C taskid program-number ipaddr port

These options are used only when ypxfr is invoked by ypserv(8) in response to a map transfer request initiated by yppush(8). In this instance, ypxfr needs to 'callback' to the yppush(8) process and interact with it, so yppush(8) passes to it an IP address ipaddr, port number port, registered program number program-number and a transaction ID taskid that it can use to contact the waiting yppush(8) process on the master server.

mapname

The name of the map to transfer.

FILES

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

The NIS maps for a particular NIS domain.

SEE ALSO

AUTHORS