ypserv, ypxfrd - NIS server and binder processes


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



     The Network Information Service (NIS) provides a simple net-
     work  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(4). 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  ser-
     vice  is described in ypclnt(3NSL). Administrative tools are
     described in yppoll(1M), yppush(1M),  ypset(1M),  ypxfr(1M),
     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(1M),
     ypmake(1M), and makedbm(1M).

     The ypserv utility is a daemon process  typically  activated
     at  system  startup from /etc/init.d/rpc. Alternatively, you
     can, as the root user, start NIS services using  ypstart(1M)
     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(1M) 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  informa-
     tion 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 sup-
     plied 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:

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

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

           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(1M), 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

     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(1M) are not used.

     It is possible that ypmake(1M) 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(1M) operation will push infor-
     mation 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

     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.


     -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 at  a  machine  running
           in.named(1M).  This  option  turns  on  DNS forwarding
           regardless of whether or not the  YP_INTERDOMAIN  flag
           is  set  in  the  hosts  maps. See makedbm(1M). 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 con-
           tainer objects have not  already  been  created,  then
           errors  will  occur,  as entries are written to nonex-
           istent 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  mes-
           sages to stderr.

     When run with the -i, -r, -I, -ir or -Ir options, the ypserv
     command  runs in the foreground and exits once map initiali-
     zation 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(1M).

     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


           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.

           Startup file that starts up basic RPC services and NIS
           by calling ypstart(1M). If the /var/yp/ypserv.log file
           exists when ypserv starts up, log information is writ-
           ten  to  it  when  error  conditions  arise.  The file
           /var/yp/binding/domainname/ypservers is used  to  list
           the NIS server hosts that ypbind can bind to.


     See attributes(5) for descriptions of the  following  attri-

    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    | Availability                | SUNWypu                     |


     ypcat(1),    ypmatch(1),     ypwhich(1),     domainname(1M),
     in.named(1M),     makedbm(1M),    ypbind(1M),    ypinit(1M),
     ypmake(1M), yppoll(1M), yppush(1M), ypset(1M),  ypstart(1M),
     ypstop(1M), ypxfr(1M), ndbm(3C), ypclnt(3NSL), libnsl(3LIB),
     NISLDAPmapping(4),  securenets(4),  ypfiles(4),   ypserv(4),

     Network Interfaces Programmer's Guide

     System Administration Guide: Naming and  Directory  Services
     (DNS, NIS, and LDAP)


     ypserv supports multiple domains. The ypserv process  deter-
     mines  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 permis-

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

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