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.Oo 47.Fl S 48.Sm off 49.Ar domainname , server1 , server2 , ... 50.Sm on 51.Oc 52.Sh DESCRIPTION 53The 54.Nm 55utility is the process that maintains NIS binding information. 56At startup, 57it searches for an NIS server responsible for serving the system's 58default domain (as set by the 59.Xr domainname 1 60command) using network broadcasts. 61Once it receives a reply, 62it will store the address of the server and other 63information in a special file located in 64.Pa /var/yp/binding . 65The NIS routines in the standard C library can then use this file 66when processing NIS requests. 67There may be several such files 68since it is possible for an NIS client to be bound to more than 69one domain. 70.Pp 71After a binding has been established, 72.Nm 73will send DOMAIN_NONACK requests to the NIS server at one minute 74intervals. 75If it fails to receive a reply to one of these requests, 76.Nm 77assumes that the server is no longer running and resumes its network 78broadcasts until another binding is established. 79The 80.Nm 81utility will also log warning messages using the 82.Xr syslog 3 83facility each time it detects that a server has stopped responding, 84as well as when it has bound to a new server. 85.Pp 86The following options are available: 87.Bl -tag -width indent 88.It Fl ypset 89It is possible to force 90.Nm 91to bind to a particular NIS server host for a given domain by using the 92.Xr ypset 8 93command. 94However, 95.Nm 96refuses YPBINDPROC_SETDOM requests by default since it has no way of 97knowing exactly who is sending them. 98Using the 99.Fl ypset 100flag causes 101.Nm 102to accept YPBINDPROC_SETDOM requests from any host. 103This option should only 104be used for diagnostic purposes and only for limited periods since allowing 105arbitrary users to reset the binding of an NIS client poses a severe 106security risk. 107.It Fl ypsetme 108This is similar to the 109.Fl ypset 110flag, except that it only permits YPBINDPROC_SETDOM requests to be processed 111if they originated from the local host. 112.It Fl s 113Cause 114.Nm 115to run in secure mode: it will refuse to bind to any NIS server 116that is not running as root (i.e. that is not using privileged 117TCP ports). 118.It Fl S Xo 119.Sm off 120.Ar domainname , server1 , server2 , server3 , ... 121.Sm on 122.Xc 123Allow the system administrator to lock 124.Nm 125to a particular 126domain and group of NIS servers. 127Up to ten servers can be specified. 128There must not be any spaces between the commas in the domain/server 129specification. 130This option is used to insure that the system binds 131only to one domain and only to one of the specified servers, which 132is useful for systems that are both NIS servers and NIS 133clients: it provides a way to restrict what machines the system can 134bind to without the need for specifying the 135.Fl ypset 136or 137.Fl ypsetme 138options, which are often considered to be security holes. 139The specified 140servers must have valid entries in the local 141.Pa /etc/hosts 142file. IP addresses may be specified in place of hostnames. 143If 144.Nm 145can't make sense ouf of the arguments, it will ignore 146the 147.Fl S 148flag and continue running normally. 149.Pp 150Note that 151.Nm 152will consider the domainname specified with the 153.Fl S 154flag to be the system default domain. 155.It Fl m 156Cause 157.Nm 158to use a 'many-cast' rather than a broadcast for choosing a server 159from the restricted mode server list. 160In many-cast mode, 161.Nm 162will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the 163servers specified in the restricted list and bind to the server that 164responds the fastest. 165This mode of operation is useful for NIS clients on remote subnets 166where no local NIS servers are available. 167The 168.Fl m 169flag can only be used in conjunction with the 170.Fl S 171flag above (if used without the 172.Fl S 173flag, it has no effect). 174.El 175.Sh NOTES 176The 177.Nm 178utility will not make continuous attempts to keep secondary domains bound. 179If a server for a secondary domain fails to respond to a ping, 180.Nm 181will broadcast for a new server only once before giving up. 182If a 183client program attempts to reference the unbound domain, 184.Nm 185will try broadcasting again. 186By contrast, 187.Nm 188will automatically maintain a binding for the default domain whether 189client programs reference it ot not. 190.Sh FILES 191.Bl -tag -width /etc/rc.conf -compact 192.It Pa /var/yp/binding/[domainname].[version] 193the files used to hold binding information for each NIS domain 194.It Pa /etc/rc.conf 195system configuration file where the system default domain and 196ypbind startup options are specified 197.El 198.Sh SEE ALSO 199.Xr domainname 1 , 200.Xr syslog 3 , 201.Xr yp 8 , 202.Xr ypserv 8 , 203.Xr ypset 8 204.Sh AUTHORS 205.An Theo de Raadt Aq deraadt@fsa.ca 206