a974cefe6e
-S domainname,server1,server2,server3,...
The -S flag allows the system administrator to lock ypbind to a
particular domain and group of NIS servers. Up to ten servers can
be specified. There must not be any spaces between the commas in
the domain/server specification. This option is used to insure that
that the system binds only to one domain and only to one of the
specified servers, which is useful for systems that are both NIS
servers and NIS clients: it provides a way to restrict what ma-
chines the system can bind to without the need for specifying the
-ypset or -ypsetme options, which are often considered to be secu-
rity holes. The specified servers must have valid entries in the
local /etc/hosts file. IP addresses may be specified in place of
hostnames. If ypbind can't make sense ouf of the arguments, it will
ignore the -S flag and continue running normally.
Note that ypbind will consider the domainname specified with the -S
flag to be the system default domain.
(According to what Garrett showed me, OSF/1 actually only allows 4 servers
to be specified. Ten seemed to be a bit more reasonable to me.)
Suggested by: G. Wollman
Idea lifted from: OSF/1
163 lines
5.9 KiB
Groff
163 lines
5.9 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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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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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.\" $Id: ypbind.8,v 1.2 1995/04/26 19:03:15 wpaul Exp $
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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 ypbind
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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 S Ar domainname,server1,server2,...
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.Sh DESCRIPTION
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.Nm ypbind
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is the process that maintains NIS binding information. 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. 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 ypbind
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will send DOMAIN_NONACK requests to the NIS server at one minute
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intervals. If it fails to receive a reply to one of these requests
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.Nm ypbind
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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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.Nm ypbind
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will also log warning messages using the syslog(3) facility each time
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it detects that a server has stopped responding, as well as when it
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has bound to a new server.
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.Pp
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.Sh OPTIONS
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The following options are supported by
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.Nm ypbind :
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.Bl -tag -width flag
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.It Fl ypset
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It is possible to force
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.Nm ypbind
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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. However,
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.Nm ypbind
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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. Using the
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.Fl ypset
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flag causes
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.Nm ypbind
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to accept YPBINDPROC_SETDOM requests from any host. 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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The
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.Fl s
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flag causes
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.Nm ypbind
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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 Ar domainname,server1,server2,server3,...
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The
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.Fl S
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flag allows the system administrator to lock ypbind to a particular
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domain and group of NIS servers. 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. This option is used to insure that 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. 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. IP addresses may be specified in place of hostnames. If
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.Nm ypbind
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can't make sense ouf 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 ypbind
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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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.Sh NOTES
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.Nm ypbind
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will not make continuous attempts to keep secondary domains bound.
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If a server for a second dary domain fails to respond to a ping,
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.Nm ypbind
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will broadcast for a new server only once before giving up. If a
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client program attempts to reference the unbound domain, ypbind will
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try broadcasting again. By contrast,
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.Nm ypbind
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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 Pa -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/sysconfig
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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 syslog 3 ,
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.Xr domainname 1 ,
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.Xr ypserv 8 ,
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.Xr ypset 8 ,
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.Xr yp 8
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.Sh AUTHOR
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Theo de Raadt <deraadt@fsa.ca>
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