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.\" $FreeBSD$ 29.\" 30.Dd April 9, 1995 31.Dt YPBIND 8 32.Os 33.Sh NAME 34.Nm ypbind 35.Nd "NIS domain binding daemon" 36.Sh SYNOPSIS 37.Nm 38.Op Fl ypset 39.Op Fl ypsetme 40.Op Fl s 41.Op Fl m 42.Oo 43.Fl S 44.Sm off 45.Ar domainname , server1 , server2 , ... 46.Sm on 47.Oc 48.Sh DESCRIPTION 49The 50.Nm 51utility is the process that maintains NIS binding information. 52At startup, 53it searches for an NIS server responsible for serving the system's 54default domain (as set by the 55.Xr domainname 1 56command) using network broadcasts. 57Once it receives a reply, 58it will store the address of the server and other 59information in a special file located in 60.Pa /var/yp/binding . 61The NIS routines in the standard C library can then use this file 62when processing NIS requests. 63There may be several such files 64since it is possible for an NIS client to be bound to more than 65one domain. 66.Pp 67After a binding has been established, 68.Nm 69will send DOMAIN_NONACK requests to the NIS server at one minute 70intervals. 71If it fails to receive a reply to one of these requests, 72.Nm 73assumes that the server is no longer running and resumes its network 74broadcasts until another binding is established. 75The 76.Nm 77utility will also log warning messages using the 78.Xr syslog 3 79facility each time it detects that a server has stopped responding, 80as well as when it has bound to a new server. 81.Pp 82The following options are available: 83.Bl -tag -width indent 84.It Fl ypset 85It is possible to force 86.Nm 87to bind to a particular NIS server host for a given domain by using the 88.Xr ypset 8 89command. 90However, 91.Nm 92refuses YPBINDPROC_SETDOM requests by default since it has no way of 93knowing exactly who is sending them. 94Using the 95.Fl ypset 96flag causes 97.Nm 98to accept YPBINDPROC_SETDOM requests from any host. 99This option should only 100be used for diagnostic purposes and only for limited periods since allowing 101arbitrary users to reset the binding of an NIS client poses a severe 102security risk. 103.It Fl ypsetme 104This is similar to the 105.Fl ypset 106flag, except that it only permits YPBINDPROC_SETDOM requests to be processed 107if they originated from the local host. 108.It Fl s 109Cause 110.Nm 111to run in secure mode: it will refuse to bind to any NIS server 112that is not running as root (i.e., that is not using privileged 113TCP ports). 114.It Fl S Xo 115.Sm off 116.Ar domainname , server1 , server2 , server3 , ... 117.Sm on 118.Xc 119Allow the system administrator to lock 120.Nm 121to a particular 122domain and group of NIS servers. 123Up to ten servers can be specified. 124There must not be any spaces between the commas in the domain/server 125specification. 126This option is used to ensure that the system binds 127only to one domain and only to one of the specified servers, which 128is useful for systems that are both NIS servers and NIS 129clients: it provides a way to restrict what machines the system can 130bind to without the need for specifying the 131.Fl ypset 132or 133.Fl ypsetme 134options, which are often considered to be security holes. 135The specified 136servers must have valid entries in the local 137.Pa /etc/hosts 138file. 139IP addresses may be specified in place of hostnames. 140If 141.Nm 142cannot make sense out of the arguments, it will ignore 143the 144.Fl S 145flag and continue running normally. 146.Pp 147Note that 148.Nm 149will consider the domainname specified with the 150.Fl S 151flag to be the system default domain. 152.It Fl m 153Cause 154.Nm 155to use a 'many-cast' rather than a broadcast for choosing a server 156from the restricted mode server list. 157In many-cast mode, 158.Nm 159will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the 160servers specified in the restricted list and bind to the server that 161responds the fastest. 162This mode of operation is useful for NIS clients on remote subnets 163where no local NIS servers are available. 164The 165.Fl m 166flag can only be used in conjunction with the 167.Fl S 168flag above (if used without the 169.Fl S 170flag, it has no effect). 171.El 172.Sh NOTES 173The 174.Nm 175utility will not make continuous attempts to keep secondary domains bound. 176If a server for a secondary domain fails to respond to a ping, 177.Nm 178will broadcast for a new server only once before giving up. 179If a 180client program attempts to reference the unbound domain, 181.Nm 182will try broadcasting again. 183By contrast, 184.Nm 185will automatically maintain a binding for the default domain whether 186client programs reference it ot not. 187.Sh FILES 188.Bl -tag -width /etc/rc.conf -compact 189.It Pa /var/yp/binding/[domainname].[version] 190the files used to hold binding information for each NIS domain 191.It Pa /etc/rc.conf 192system configuration file where the system default domain and 193ypbind startup options are specified 194.El 195.Sh SEE ALSO 196.Xr domainname 1 , 197.Xr syslog 3 , 198.Xr yp 8 , 199.Xr ypserv 8 , 200.Xr ypset 8 201.Sh AUTHORS 202.An Theo de Raadt Aq Mt deraadt@fsa.ca 203