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 53.Nm Ypbind 54is the process that maintains NIS binding information. 55At startup, 56it searches for an NIS server responsible for serving the system's 57default domain (as set by the 58.Xr domainname 1 59command) using network broadcasts. 60Once it receives a reply, 61it will store the address of the server and other 62information in a special file located in 63.Pa /var/yp/binding . 64The NIS routines in the standard C library can then use this file 65when processing NIS requests. 66There may be several such files 67since it is possible for an NIS client to be bound to more than 68one domain. 69.Pp 70After a binding has been established, 71.Nm 72will send DOMAIN_NONACK requests to the NIS server at one minute 73intervals. 74If it fails to receive a reply to one of these requests, 75.Nm 76assumes that the server is no longer running and resumes its network 77broadcasts until another binding is established. 78.Nm Ypbind 79will also log warning messages using the 80.Xr syslog 3 81facility each time it detects that a server has stopped responding, 82as well as when it has bound to a new server. 83.Pp 84The following options are available: 85.Bl -tag -width indent 86.It Fl ypset 87It is possible to force 88.Nm 89to bind to a particular NIS server host for a given domain by using the 90.Xr ypset 8 91command. 92However, 93.Nm 94refuses YPBINDPROC_SETDOM requests by default since it has no way of 95knowing exactly who is sending them. 96Using the 97.Fl ypset 98flag causes 99.Nm 100to accept YPBINDPROC_SETDOM requests from any host. 101This option should only 102be used for diagnostic purposes and only for limited periods since allowing 103arbitrary users to reset the binding of an NIS client poses a severe 104security risk. 105.It Fl ypsetme 106This is similar to the 107.Fl ypset 108flag, except that it only permits YPBINDPROC_SETDOM requests to be processed 109if they originated from the local host. 110.It Fl s 111Cause 112.Nm 113to run in secure mode: it will refuse to bind to any NIS server 114that is not running as root (i.e. that is not using privileged 115TCP ports). 116.It Fl S Xo 117.Sm off 118.Ar domainname , server1 , server2 , server3 , ... 119.Sm on 120.Xc 121Allow the system administrator to lock 122.Nm 123to a particular 124domain and group of NIS servers. 125Up to ten servers can be specified. 126There must not be any spaces between the commas in the domain/server 127specification. 128This option is used to insure that the system binds 129only to one domain and only to one of the specified servers, which 130is useful for systems that are both NIS servers and NIS 131clients: it provides a way to restrict what machines the system can 132bind to without the need for specifying the 133.Fl ypset 134or 135.Fl ypsetme 136options, which are often considered to be security holes. 137The specified 138servers must have valid entries in the local 139.Pa /etc/hosts 140file. IP addresses may be specified in place of hostnames. 141If 142.Nm 143can't make sense ouf 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 176program 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