Tribblix: manual page: ypserv.8

YPSERV(8) Maintenance Commands and Procedures YPSERV(8)

NAME

ypserv, ypxfrd - NIS server and binder processes

SYNOPSIS

/usr/lib/netsvc/yp/ypserv [-dv] [-i | -I] [-r | -R]

/usr/lib/netsvc/yp/ypxfrd

DESCRIPTION

The Network Information Service (NIS) provides a simple network
lookup service consisting of databases and processes. The databases
are ndbm files in a directory tree rooted at /var/yp. See ndbm(3C).
These files are described in ypfiles(5). The processes are
/usr/lib/netsvc/yp/ypserv, the NIS database lookup server, and
/usr/lib/netsvc/yp/ypbind, the NIS binder. The programmatic interface
to the NIS service is described in ypclnt(3NSL). Administrative
tools are described in yppoll(8), yppush(8), ypset(8), ypxfr(8), and
ypwhich(1). Tools to see the contents of NIS maps are described in
ypcat(1), and ypmatch(1). Database generation and maintenance tools
are described in ypinit(8), ypmake(8), and makedbm(8).

The ypserv utility is a daemon process typically activated at system
startup from svc:/network/nis/server:default. Alternatively, you can,
as the root user, start NIS services using ypstart(8) from the
command-line. ypserv runs only on NIS server machines with a complete
NIS database. You can halt all NIS services using the ypstop(8)
command.

The ypxfrd utility transfers entire NIS maps in an efficient manner.
For systems that use this daemon, map transfers are 10 to 100 times
faster, depending on the map. To use this daemon, be sure ypxfrd is
running on the master server. See /usr/lib/netsvc/yp/ypstart. ypxfr
attempts to use ypxfrd first. If that fails, it prints a warning,
then uses the older transfer method.

The ypserv daemon's primary function is to look up information in its
local database of NIS maps.

The operations performed by ypserv are defined for the implementor by
the YP Protocol Specification, and for the programmer by the header
file <rpcsvc/yp_prot.h>.

Communication to and from ypserv is by means of RPC calls. Lookup
functions are described in ypclnt(3NSL), and are supplied as C-
callable functions in the libnsl(3LIB) library. There are four lookup
functions, all of which are performed on a specified map within some
NIS domain: yp_match(3NSL), yp_first(3NSL), yp_next(3NSL), and
yp_all(3NSL). The yp_match operation takes a key, and returns the
associated value. The yp_first operation returns the first key-value
pair from the map, and yp_next can be used to enumerate the
remainder. yp_all ships the entire map to the requester as the
response to a single RPC request.

A number of special keys in the DBM files can alter the way in which
ypserv operates. The keys of interest are:

YP_INTERDOMAIN
The presence of this key causes ypserv to
forward to a DNS server host lookups that cannot
be satisfied by the DBM files.

YP_SECURE
This key causes ypserv to answer only questions
coming from clients on reserved ports.

YP_MULTI_hostname
This is a special key in the form,
YP_MULTI_hostname addr1,...,addrN. A client
looking for hostname receives the closest
address.

Two other functions supply information about the map, rather than map
entries: yp_order(3NSL), and yp_master(3NSL). In fact, both order
number and master name exist in the map as key-value pairs, but the
server will not return either through the normal lookup functions. If
you examine the map with makedbm(8), however, they are visible. Other
functions are used within the NIS service subsystem itself, and are
not of general interest to NIS clients. These functions include
do_you_serve_this_domain?, transfer_map, and
reinitialize_internal_state.

On start up, ypserv checks for the existence of the NIS to LDAP (N2L)
configuration file /var/yp/NISLDAPmapping. If it is present then a
master server starts in N2L mode. If the file is not present it
starts in "traditional" (non N2L) mode. Slave servers always start in
traditional mode.

In N2L mode, a new set of map files, with an LDAP_ prefix, are
generated, based on the contents of the LDAP DIT. The old map files,
NIS source files and ypmake(8) are not used.

It is possible that ypmake(8) can be accidentally run in N2L mode. If
the occurs, the old style map files are overwritten. That the map
files are overwritten is harmless. However, any resulting yppush(8)
operation will push information based on the DIT rather than the
source files. The user may not expect information based on the DIT.
ypserv keeps track of the last modification date of the old style map
files. If the map files have been updated, a warning is logged that
suggests that the user call yppush directly instead of ypmake.

If a server attempts to run in N2L mode and a LDAP server cannot be
contacted, it behaves as follows:

1. When ypserv is started, a warning will be logged.

2. When a NIS read access is made and the TTL entry has
expired, a warning is logged.Information that is returned
from the cache has not been updated.

3. When a NIS write access is made, a warning is logged. The
cache will not be updated, and a NIS failure will be
returned.

If ypxfrd is running in N2L mode and is asked to transfer a map,
ypxfrd first checks whether the map is out of date. If the map is out
of date, ypxfrd initiates an update from the DIT. ypxfrd cannot wait
for the update to complete. If ypxfrd waited, the client end ypxfr
operation could time out. To prevent ypxfrd from timing out, the
existing map is transferred from the cache. The most up to date map
will be transferred on subsequent ypxfrd operations.

OPTIONS

ypserv
-d
The NIS service should go to the DNS for more host
information. This requires the existence of a correct
/etc/resolv.conf file pointing to a DNS server. This option
turns on DNS forwarding regardless of whether or not the
YP_INTERDOMAIN flag is set in the hosts maps. See makedbm(8).
In the absence of an /etc/resolv.conf file, ypserv complains,
but ignores the -d option.

-i
If in N2L mode, initialize the NIS related parts of the DIT
based on the current, non LDAP_ prefixed, map files. The LDAP_
prefixed maps are not created or updated. If you require that
LDAP_ prefixed maps be updated or created, then use the -ir
option.

The -i option does not attempt to create any NIS domain or
container objects. If any NIS domain or container objects have
not already been created, then errors will occur, as entries
are written to nonexistent containers.

-I
Identical to -i, except that any missing domain and container
objects are created.

-r
If in N2L mode, then refresh the LDAP_ prefixed map files
based on the contents of the DIT.

-ir
If both -i and -r are specified in N2L mode, then the DIT will
first be initialized from the current non LDAP_ prefixed map
files. A new set of LDAP_ prefixed maps will then be
generated from the contents of the DIT. A new set of LDAP_
prefixed maps is required when moving from traditional NIS to
N2L mode NIS.

-Ir
Identical to -ir, except that any missing domain and container
objects are created.

-v
Operate in the verbose mode, printing diagnostic messages to
stderr.

When run with the -i, -r, -I, -ir or -Ir options, the ypserv command
runs in the foreground and exits once map initialization has been
completed. Once the ypserv command exits, the user knows the maps are
ready and can restart ypserv and the other yp daemons by running
ypstart(8).

If there is a requirement to initialize the DIT from the NIS source
files, which may have been modified since the maps were last remade,
run ypmake before running ypserv -i or ypserv -ir. ypmake
regenerated old style NIS maps. Then ypserv -ir dumps them into the
DIT. When the -ir option is used, the LDAP_ prefixe maps are also
generated or updated. Since these maps will be more recent than the
old style maps, ypmake will not be reported as erroneous when it is
run.

FILES

/var/yp/securenets

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

/var/yp/ypserv.log

If the /var/yp/ypserv.log file exists when ypserv starts up, log
information is written to it when error conditions arise.

/var/yp/binding/domainname/ypservers

Lists the NIS server hosts that ypbind can bind to.

NOTES

ypserv supports multiple domains. The ypserv process determines the
domains it serves by looking for directories of the same name in the
directory /var/yp. It replies to all broadcasts requesting yp service
for that domain.

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 must not be used without permission.

NIS uses ndbm() files to store maps. Therefore, it is subject to the
1024 byte limitations described in the USAGE and NOTES sections of
the ndbm(3C) man page.

The NIS server service is managed by the service management facility,
smf(7), under the service identifier:

svc:/network/nis/server:default

Administrative actions on this service, such as enabling, disabling,
or requesting restart, can be performed using svcadm(8). The
service's status can be queried using the svcs(1) command.

December 15, 2004 YPSERV(8)

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

FILES

SEE ALSO

NOTES