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.\" $Id: ypbind.8,v 1.9 1997/04/15 07:15:47 jmg Exp $ 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 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 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.Pp 76.Sh OPTIONS 77The following options are supported by 78.Nm Ns : 79.Bl -tag -width flag 80.It Fl ypset 81It is possible to force 82.Nm 83to bind to a particular NIS server host for a given domain by using the 84.Xr ypset 8 85command. However, 86.Nm 87refuses YPBINDPROC_SETDOM requests by default since it has no way of 88knowing exactly who is sending them. Using the 89.Fl ypset 90flag causes 91.Nm 92to accept YPBINDPROC_SETDOM requests from any host. This option should only 93be used for diagnostic purposes and only for limited periods since allowing 94arbitrary users to reset the binding of an NIS client poses a severe 95security risk. 96.It Fl ypsetme 97This is similar to the 98.Fl ypset 99flag, except that it only permits YPBINDPROC_SETDOM requests to be processed 100if they originated from the local host. 101.It Fl s 102The 103.Fl s 104flag causes 105.Nm 106to run in secure mode: it will refuse to bind to any NIS server 107that is not running as root (i.e. that is not using privileged 108TCP ports). 109.It Fl S Ar domainname,server1,server2,server3,... 110The 111.Fl S 112flag allows the system administrator to lock ypbind to a particular 113domain and group of NIS servers. Up to ten servers can be specified. 114There must not be any spaces between the commas in the domain/server 115specification. This option is used to insure that the system binds 116only to one domain and only to one of the specified servers, which 117is useful for systems that are both NIS servers and NIS 118clients: it provides a way to restrict what machines the system can 119bind to without the need for specifying the 120.Fl ypset 121or 122.Fl ypsetme 123options, which are often considered to be security holes. The specified 124servers must have valid entries in the local 125.Pa /etc/hosts 126file. IP addresses may be specified in place of hostnames. If 127.Nm 128can't make sense ouf of the arguments, it will ignore 129the 130.Fl S 131flag and continue running normally. 132.Pp 133Note that 134.Nm 135will consider the domainname specified with the 136.Fl S 137flag to be the system default domain. 138.It Fl m 139The 140.Fl m 141flag can only be used in conjunction with the 142.Fl S 143flag above (if used without the 144.Fl S 145flag, it has no effect). It causes 146.Nm ypbind 147to use a 'many-cast' rather than a broadcast for choosing a server 148from the restricted mode server list. In many-cast mode, 149.Nm ypbind 150will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the 151servers specified in the restricted list and bind to the server that 152responds the fastest. 153This mode of operation is useful for NIS clients on remote subnets 154where no local NIS servers are available. 155.El 156.Sh NOTES 157The 158.Nm 159program will not make continuous attempts to keep secondary domains bound. 160If a server for a secondary domain fails to respond to a ping, 161.Nm 162will broadcast for a new server only once before giving up. If a 163client program attempts to reference the unbound domain, 164.Nm 165will try broadcasting again. By contrast, 166.Nm 167will automatically maintain a binding for the default domain whether 168client programs reference it ot not. 169.Sh FILES 170.Bl -tag -width Pa -compact 171.It Pa /var/yp/binding/[domainname].[version] 172The files used to hold binding information for each NIS domain. 173.It Pa /etc/sysconfig 174System configuration file where the system default domain and 175ypbind startup options are specified. 176.El 177.Sh SEE ALSO 178.Xr domainname 1 , 179.Xr syslog 3 , 180.Xr yp 4 , 181.Xr ypserv 8 , 182.Xr ypset 8 183.Sh AUTHOR 184Theo de Raadt <deraadt@fsa.ca> 185