nis, yp —
description of the NIS (formerly YP) subsystem
  
    | ypset | [ -hhost]
      [-ddomain]
      server | 
  
    | yppoll | [ -hhost]
      [-ddomain]
      mapname | 
  
    | ypcat | [ -kt] [-ddomainname] mapname | 
  
    | ypmatch | [ -kt] [-ddomainname] key ...
      mapname | 
  
    | ypwhich | [ -ddomain]
      [[-t]-m[mname] | host] | 
  
    | yppush | [ -ddomainname]
      [-hhostname]
      [-v] mapname | 
  
    | ypxfr | [ -bcf] [-ddomain] [-hhost] [-sdomain] [-Ctid prog ipadd port]
      mapname | 
  
    | ypinit | -smaster_server
      [domainname] | 
  
    | rpc.yppasswdd | [ -noshell] [-nogecos]
      [-nopw] [-marg1 arg2 ...] | 
The NIS subsystem allows network management of passwd and group file entries
  through the functions
  getpwent(3) and
  getgrent(3). NIS also provides
  hooks for other client programs, such as
  amd(8) and
  rpc.bootparamd(8), that
  can use NIS maps.
Password maps in standard YP are insecure, because the pw_passwd
    field is accessible by any user. A common solution to this is to generate a
    secure map (using “makedbm -s”) which can only be accessed by
    a client bound to a privileged port. To activate the secure map, see the
    appropriate comment in /var/yp/Makefile.yp.
The NIS subsystem is conditionally started in
    /etc/rc. See the
    /etc/rc.conf file for configuration variables.
domainname(1),
  ypcat(1),
  ypmatch(1),
  ypwhich(1),
  ypclnt(3),
  group(5),
  hosts_access(5),
  nsswitch.conf(5),
  passwd(5),
  rc.conf(5),
  rc(8),
  ypbind(8),
  ypinit(8),
  yppoll(8),
  yppush(8),
  ypserv(8),
  ypset(8),
  yptest(8),
  ypxfr(8)
The NIS client subsystem was originally written by Theo de Raadt to be
  compatible with Sun's implementation. The NIS server suite was originally
  written by Mats O Jansson.
If ypbind(8) cannot find a server,
  the system behaves the same way as Sun's code: it hangs.
The ‘secure map’ feature is not compatible with
    non-BSD implementations as found e.g. in Solaris.