YPFILES(5) File Formats and Configurations YPFILES(5)

NAME

ypfiles - Network Information Service Version 2, formerly known as YP

DESCRIPTION

The NIS network information service uses a distributed, replicated
database of dbm files, in ASCII form, that are contained in the
/var/yp directory hierarchy on each NIS server.


A dbm database served by the NIS server is called a NIS map. A NIS
domain is a subdirectory of /var/yp that contains a set of NIS maps
on each NIS server.


Standard nicknames are defined in the file /var/yp/nicknames. These
names can be used in place of the full map name in the ypmatch and
ypcat commands. Use the command ypwhich -x to display the current set
of nicknames. Use the command ypwhich -m to display all the available
maps. Each line of the nickname file contains two fields separated by
white space. The first field is the nickname, and the second field is
the name of the map that it expands to. The nickname cannot contain a
".".

NIS to LDAP (N2L)
If the /var/yp/NISLDAPmapping configuration file is present, the NIS
server operates in NIS to LDAP (N2L) mode. In this mode, NIS maps are
stored in a new set of DBM files, prepended by the LDAP_ prefix, at
/var/yp/domainname. These files are used as a cache backed by
information from an LDAP server. Additional DBM files are created in
the same directory to hold the cache's TTL values.


N2L mode enables NIS clients to be supported in an LDAP environment.


In N2L mode, the old style DBM files, NIS source files, and the
ypmake(8) utility have to role. They are retained to enable easy
conversion back to the traditional mode, if required.

Converting from N2L to Traditional NIS
When NIS is operating in N2L mode, it uses a new set of NIS maps with
an LDAP_ prefix, based on the contents of the LDAP DIT. The NIS
source files are unused and become out of date. If you wish to
convert back to the traditional NIS mode, the N2L configuration file
should be deleted. The system will then return to using the standard
map files. Optionally, the N2L mode map files, /var/yp/*/LDAP_* can
also be deleted.


If you want to run the system in traditional mode with information
based on the DIT, then the NIS source files must be regenerated based
on the N2L maps. To regenerate the NIS source files based on the N2L
maps, run ypmap2src(8).

FILES

/var/yp

Directory containing NIS configuration files.


/var/yp/binding

Stores the information required to bind the NIS client to the NIS
server.


/var/yp/binding/ypdomain/ypservers

Contains the servers to which the NIS client is allowed to bind.


/var/yp/Makefile

Builds the NIS ndbm databases.


/var/yp/nicknames

Nicknames file.


/var/yp/securenets

Defines the hosts and networks that are granted access to
information in the served domain. This file is read at startup
time by ypserv and ypxfrd.


/var/yp/ypdomain

Directory containing ndbm databases.


/var/yp/NISLDAPmapping

NIS to LDAP configuration file


/var/yp/*/LDAP_*

NIS to LDAP mode map files

SEE ALSO

ldap(1), ndbm(3C), ypclnt(3NSL), makedbm(8), ypbind(8), ypinit(8),
ypmake(8), ypmap2src(8), ypserv(8), ypxfrd(8)

February 17, 2023 YPFILES(5)