203 lines
6.1 KiB
Groff
203 lines
6.1 KiB
Groff
.\" Copyright (c) 1991, 1993, 1995
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd April 9, 1995
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.Dt YPBIND 8
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.Os
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.Sh NAME
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.Nm ypbind
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.Nd "NIS domain binding daemon"
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.Sh SYNOPSIS
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.Nm
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.Op Fl ypset
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.Op Fl ypsetme
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.Op Fl s
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.Op Fl m
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.Oo
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.Fl S
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.Sm off
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.Ar domainname , server1 , server2 , ...
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.Sm on
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.Oc
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.Sh DESCRIPTION
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The
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.Nm
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utility is the process that maintains NIS binding information.
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At startup,
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it searches for an NIS server responsible for serving the system's
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default domain (as set by the
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.Xr domainname 1
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command) using network broadcasts.
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Once it receives a reply,
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it will store the address of the server and other
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information in a special file located in
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.Pa /var/yp/binding .
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The NIS routines in the standard C library can then use this file
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when processing NIS requests.
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There may be several such files
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since it is possible for an NIS client to be bound to more than
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one domain.
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.Pp
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After a binding has been established,
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.Nm
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will send DOMAIN_NONACK requests to the NIS server at one minute
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intervals.
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If it fails to receive a reply to one of these requests,
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.Nm
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assumes that the server is no longer running and resumes its network
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broadcasts until another binding is established.
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The
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.Nm
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utility will also log warning messages using the
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.Xr syslog 3
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facility each time it detects that a server has stopped responding,
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as well as when it has bound to a new server.
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.Pp
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The following options are available:
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.Bl -tag -width indent
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.It Fl ypset
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It is possible to force
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.Nm
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to bind to a particular NIS server host for a given domain by using the
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.Xr ypset 8
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command.
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However,
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.Nm
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refuses YPBINDPROC_SETDOM requests by default since it has no way of
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knowing exactly who is sending them.
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Using the
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.Fl ypset
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flag causes
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.Nm
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to accept YPBINDPROC_SETDOM requests from any host.
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This option should only
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be used for diagnostic purposes and only for limited periods since allowing
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arbitrary users to reset the binding of an NIS client poses a severe
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security risk.
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.It Fl ypsetme
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This is similar to the
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.Fl ypset
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flag, except that it only permits YPBINDPROC_SETDOM requests to be processed
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if they originated from the local host.
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.It Fl s
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Cause
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.Nm
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to run in secure mode: it will refuse to bind to any NIS server
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that is not running as root (i.e., that is not using privileged
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TCP ports).
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.It Fl S Xo
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.Sm off
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.Ar domainname , server1 , server2 , server3 , ...
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.Sm on
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.Xc
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Allow the system administrator to lock
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.Nm
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to a particular
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domain and group of NIS servers.
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Up to ten servers can be specified.
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There must not be any spaces between the commas in the domain/server
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specification.
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This option is used to ensure that the system binds
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only to one domain and only to one of the specified servers, which
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is useful for systems that are both NIS servers and NIS
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clients: it provides a way to restrict what machines the system can
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bind to without the need for specifying the
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.Fl ypset
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or
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.Fl ypsetme
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options, which are often considered to be security holes.
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The specified
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servers must have valid entries in the local
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.Pa /etc/hosts
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file.
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IP addresses may be specified in place of hostnames.
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If
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.Nm
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cannot make sense out of the arguments, it will ignore
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the
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.Fl S
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flag and continue running normally.
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.Pp
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Note that
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.Nm
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will consider the domainname specified with the
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.Fl S
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flag to be the system default domain.
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.It Fl m
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Cause
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.Nm
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to use a 'many-cast' rather than a broadcast for choosing a server
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from the restricted mode server list.
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In many-cast mode,
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.Nm
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will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the
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servers specified in the restricted list and bind to the server that
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responds the fastest.
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This mode of operation is useful for NIS clients on remote subnets
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where no local NIS servers are available.
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The
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.Fl m
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flag can only be used in conjunction with the
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.Fl S
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flag above (if used without the
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.Fl S
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flag, it has no effect).
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.El
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.Sh NOTES
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The
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.Nm
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utility will not make continuous attempts to keep secondary domains bound.
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If a server for a secondary domain fails to respond to a ping,
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.Nm
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will broadcast for a new server only once before giving up.
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If a
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client program attempts to reference the unbound domain,
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.Nm
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will try broadcasting again.
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By contrast,
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.Nm
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will automatically maintain a binding for the default domain whether
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client programs reference it ot not.
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.Sh FILES
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.Bl -tag -width /etc/rc.conf -compact
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.It Pa /var/yp/binding/[domainname].[version]
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the files used to hold binding information for each NIS domain
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.It Pa /etc/rc.conf
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system configuration file where the system default domain and
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ypbind startup options are specified
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.El
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.Sh SEE ALSO
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.Xr domainname 1 ,
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.Xr syslog 3 ,
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.Xr yp 8 ,
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.Xr ypserv 8 ,
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.Xr ypset 8
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.Sh AUTHORS
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.An Theo de Raadt Aq deraadt@fsa.ca
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