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.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $FreeBSD: src/usr.sbin/ypbind/ypbind.8,v 1.23 2005/02/13 22:25:33 ru Exp $ 29.\" $DragonFly: src/usr.sbin/ypbind/ypbind.8,v 1.2 2003/06/17 04:30:04 dillon Exp $ 30.\" 31.Dd April 9, 1995 32.Dt YPBIND 8 33.Os 34.Sh NAME 35.Nm ypbind 36.Nd "NIS domain binding daemon" 37.Sh SYNOPSIS 38.Nm 39.Op Fl ypset 40.Op Fl ypsetme 41.Op Fl s 42.Op Fl m 43.Oo 44.Fl S 45.Sm off 46.Ar domainname , server1 , server2 , ... 47.Sm on 48.Oc 49.Sh DESCRIPTION 50The 51.Nm 52utility is the process that maintains NIS binding information. 53At startup, 54it searches for an NIS server responsible for serving the system's 55default domain (as set by the 56.Xr domainname 1 57command) using network broadcasts. 58Once it receives a reply, 59it will store the address of the server and other 60information in a special file located in 61.Pa /var/yp/binding . 62The NIS routines in the standard C library can then use this file 63when processing NIS requests. 64There may be several such files 65since it is possible for an NIS client to be bound to more than 66one domain. 67.Pp 68After a binding has been established, 69.Nm 70will send DOMAIN_NONACK requests to the NIS server at one minute 71intervals. 72If it fails to receive a reply to one of these requests, 73.Nm 74assumes that the server is no longer running and resumes its network 75broadcasts until another binding is established. 76The 77.Nm 78utility will also log warning messages using the 79.Xr syslog 3 80facility each time it detects that a server has stopped responding, 81as well as when it has bound to a new server. 82.Pp 83The following options are available: 84.Bl -tag -width indent 85.It Fl ypset 86It is possible to force 87.Nm 88to bind to a particular NIS server host for a given domain by using the 89.Xr ypset 8 90command. 91However, 92.Nm 93refuses YPBINDPROC_SETDOM requests by default since it has no way of 94knowing exactly who is sending them. 95Using the 96.Fl ypset 97flag causes 98.Nm 99to accept YPBINDPROC_SETDOM requests from any host. 100This option should only 101be used for diagnostic purposes and only for limited periods since allowing 102arbitrary users to reset the binding of an NIS client poses a severe 103security risk. 104.It Fl ypsetme 105This is similar to the 106.Fl ypset 107flag, except that it only permits YPBINDPROC_SETDOM requests to be processed 108if they originated from the local host. 109.It Fl s 110Cause 111.Nm 112to run in secure mode: it will refuse to bind to any NIS server 113that is not running as root (i.e., that is not using privileged 114TCP ports). 115.It Fl S Xo 116.Sm off 117.Ar domainname , server1 , server2 , server3 , ... 118.Sm on 119.Xc 120Allow the system administrator to lock 121.Nm 122to a particular 123domain and group of NIS servers. 124Up to ten servers can be specified. 125There must not be any spaces between the commas in the domain/server 126specification. 127This option is used to insure that the system binds 128only to one domain and only to one of the specified servers, which 129is useful for systems that are both NIS servers and NIS 130clients: it provides a way to restrict what machines the system can 131bind to without the need for specifying the 132.Fl ypset 133or 134.Fl ypsetme 135options, which are often considered to be security holes. 136The specified 137servers must have valid entries in the local 138.Pa /etc/hosts 139file. 140IP addresses may be specified in place of hostnames. 141If 142.Nm 143cannot make sense out of the arguments, it will ignore 144the 145.Fl S 146flag and continue running normally. 147.Pp 148Note that 149.Nm 150will consider the domainname specified with the 151.Fl S 152flag to be the system default domain. 153.It Fl m 154Cause 155.Nm 156to use a 'many-cast' rather than a broadcast for choosing a server 157from the restricted mode server list. 158In many-cast mode, 159.Nm 160will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the 161servers specified in the restricted list and bind to the server that 162responds the fastest. 163This mode of operation is useful for NIS clients on remote subnets 164where no local NIS servers are available. 165The 166.Fl m 167flag can only be used in conjunction with the 168.Fl S 169flag above (if used without the 170.Fl S 171flag, it has no effect). 172.El 173.Sh NOTES 174The 175.Nm 176utility will not make continuous attempts to keep secondary domains bound. 177If a server for a secondary domain fails to respond to a ping, 178.Nm 179will broadcast for a new server only once before giving up. 180If a 181client program attempts to reference the unbound domain, 182.Nm 183will try broadcasting again. 184By contrast, 185.Nm 186will automatically maintain a binding for the default domain whether 187client programs reference it ot not. 188.Sh FILES 189.Bl -tag -width /etc/rc.conf -compact 190.It Pa /var/yp/binding/[domainname].[version] 191the files used to hold binding information for each NIS domain 192.It Pa /etc/rc.conf 193system configuration file where the system default domain and 194ypbind startup options are specified 195.El 196.Sh SEE ALSO 197.Xr domainname 1 , 198.Xr syslog 3 , 199.Xr yp 8 , 200.Xr ypserv 8 , 201.Xr ypset 8 202.Sh AUTHORS 203.An Theo de Raadt Aq deraadt@fsa.ca 204