1.\" Copyright (c) 1991, 1993, 1995 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" $FreeBSD$ 33.\" 34.Dd April 9, 1995 35.Dt YPBIND 8 36.Os 37.Sh NAME 38.Nm ypbind 39.Nd "NIS domain binding daemon" 40.Sh SYNOPSIS 41.Nm 42.Op Fl ypset 43.Op Fl ypsetme 44.Op Fl s 45.Op Fl m 46.Op Fl S Ar domainname,server1,server2,... 47.Sh DESCRIPTION 48.Nm Ypbind 49is the process that maintains NIS binding information. At startup, 50it searches for an NIS server responsible for serving the system's 51default domain (as set by the 52.Xr domainname 1 53command) using network broadcasts. 54Once it receives a reply, 55it will store the address of the server and other 56information in a special file located in 57.Pa /var/yp/binding . 58The NIS routines in the standard C library can then use this file 59when processing NIS requests. There may be several such files 60since it is possible for an NIS client to be bound to more than 61one domain. 62.Pp 63After a binding has been established, 64.Nm 65will send DOMAIN_NONACK requests to the NIS server at one minute 66intervals. If it fails to receive a reply to one of these requests, 67.Nm 68assumes that the server is no longer running and resumes its network 69broadcasts until another binding is established. 70.Nm Ypbind 71will also log warning messages using the 72.Xr syslog 3 73facility each time it detects that a server has stopped responding, 74as well as when it has bound to a new server. 75.Sh OPTIONS 76The following options are supported by 77.Nm Ns : 78.Bl -tag -width indent 79.It Fl ypset 80It is possible to force 81.Nm 82to bind to a particular NIS server host for a given domain by using the 83.Xr ypset 8 84command. However, 85.Nm 86refuses YPBINDPROC_SETDOM requests by default since it has no way of 87knowing exactly who is sending them. Using the 88.Fl ypset 89flag causes 90.Nm 91to accept YPBINDPROC_SETDOM requests from any host. This option should only 92be used for diagnostic purposes and only for limited periods since allowing 93arbitrary users to reset the binding of an NIS client poses a severe 94security risk. 95.It Fl ypsetme 96This is similar to the 97.Fl ypset 98flag, except that it only permits YPBINDPROC_SETDOM requests to be processed 99if they originated from the local host. 100.It Fl s 101Cause 102.Nm 103to run in secure mode: it will refuse to bind to any NIS server 104that is not running as root (i.e. that is not using privileged 105TCP ports). 106.It Fl S Ar domainname,server1,server2,server3,... 107Allow the system administrator to lock 108.Nm 109to a particular 110domain and group of NIS servers. Up to ten servers can be specified. 111There must not be any spaces between the commas in the domain/server 112specification. This option is used to insure that the system binds 113only to one domain and only to one of the specified servers, which 114is useful for systems that are both NIS servers and NIS 115clients: it provides a way to restrict what machines the system can 116bind to without the need for specifying the 117.Fl ypset 118or 119.Fl ypsetme 120options, which are often considered to be security holes. The specified 121servers must have valid entries in the local 122.Pa /etc/hosts 123file. IP addresses may be specified in place of hostnames. If 124.Nm 125can't make sense ouf of the arguments, it will ignore 126the 127.Fl S 128flag and continue running normally. 129.Pp 130Note that 131.Nm 132will consider the domainname specified with the 133.Fl S 134flag to be the system default domain. 135.It Fl m 136Cause 137.Nm 138to use a 'many-cast' rather than a broadcast for choosing a server 139from the restricted mode server list. In many-cast mode, 140.Nm 141will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the 142servers specified in the restricted list and bind to the server that 143responds the fastest. 144This mode of operation is useful for NIS clients on remote subnets 145where no local NIS servers are available. The 146.Fl m 147flag can only be used in conjunction with the 148.Fl S 149flag above (if used without the 150.Fl S 151flag, it has no effect). 152.El 153.Sh NOTES 154The 155.Nm 156program will not make continuous attempts to keep secondary domains bound. 157If a server for a secondary domain fails to respond to a ping, 158.Nm 159will broadcast for a new server only once before giving up. If a 160client program attempts to reference the unbound domain, 161.Nm 162will try broadcasting again. By contrast, 163.Nm 164will automatically maintain a binding for the default domain whether 165client programs reference it ot not. 166.Sh FILES 167.Bl -tag -width /etc/rc.conf -compact 168.It Pa /var/yp/binding/[domainname].[version] 169the files used to hold binding information for each NIS domain 170.It Pa /etc/rc.conf 171system configuration file where the system default domain and 172ypbind startup options are specified 173.El 174.Sh SEE ALSO 175.Xr domainname 1 , 176.Xr syslog 3 , 177.Xr yp 4 , 178.Xr ypserv 8 , 179.Xr ypset 8 180.Sh AUTHORS 181.An Theo de Raadt Aq deraadt@fsa.ca 182