ypfiles - Network Information Service Version 2, formerly
knows as YP
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
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/domainename.
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
In N2L mode, the old style DBM files, NIS source files, and
the ypmake(1M) utility have to role. They are retained to
enable easy conversion back to the traditional mode, if
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 The NIS source files are unused and become out of date.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(1M).
NIS+ also provides a NIS service when it runs in YP-
compatibility mode. See nis+(1) and rpc.nisd(1M). NIS+, in
any mode, cannot be run on the same system as ypserv,
whether ypserv is in traditional or N2L mode.
Directory containing NIS configuration files.
Stores the information required to bind the NIS client
to the NIS server.
Contains the servers to which the NIS client is
allowed to bind.
Builds the NIS ndbm databases.
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.
Directory containing ndbm databases.
NIS to LDAP configuration file
NIS to LDAP mode map files
ldap(1), nis+(1), makedbm(1M), nisaddent(1M), nissetup(1M),
rpc.nisd(1M), ypbind(1M), ypinit(1M), ypmake(1M),
ypmap2src(1M), ypserv(1M), ypxfrd(1M), ndbm(3C),
The NIS+ server, rpc.nisd, when run in "YP-compatibility
mode", can support NIS clients only for the standard NIS
maps listed below, provided that it has been set up to serve
the corresponding NIS+ tables using nissetup(1M) and
nisaddent(1M). The NIS+ server should serve the directory
with the same name (case sensitive) as the domainname of the
NIS client. NIS+ servers use secure RPC to verify client
credentials but the NIS clients do not authenticate their
requests using secure RPC. Therefore, NIS clients can look
up the information stored by the NIS+ server only if the
information has "read" access for an unauthenticated client,
that is, one with nobody NIS+ credentials.
Man(1) output converted with