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.Op Fl S Ar domainname,server1,server2,... 47.Sh DESCRIPTION 48.Nm Ypbind 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 Ypbind 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 76The following options are available: 77.Bl -tag -width indent 78.It Fl ypset 79It is possible to force 80.Nm 81to bind to a particular NIS server host for a given domain by using the 82.Xr ypset 8 83command. However, 84.Nm 85refuses YPBINDPROC_SETDOM requests by default since it has no way of 86knowing exactly who is sending them. Using the 87.Fl ypset 88flag causes 89.Nm 90to accept YPBINDPROC_SETDOM requests from any host. This option should only 91be used for diagnostic purposes and only for limited periods since allowing 92arbitrary users to reset the binding of an NIS client poses a severe 93security risk. 94.It Fl ypsetme 95This is similar to the 96.Fl ypset 97flag, except that it only permits YPBINDPROC_SETDOM requests to be processed 98if they originated from the local host. 99.It Fl s 100Cause 101.Nm 102to run in secure mode: it will refuse to bind to any NIS server 103that is not running as root (i.e. that is not using privileged 104TCP ports). 105.It Fl S Ar domainname,server1,server2,server3,... 106Allow the system administrator to lock 107.Nm 108to a particular 109domain and group of NIS servers. Up to ten servers can be specified. 110There must not be any spaces between the commas in the domain/server 111specification. This option is used to insure that the system binds 112only to one domain and only to one of the specified servers, which 113is useful for systems that are both NIS servers and NIS 114clients: it provides a way to restrict what machines the system can 115bind to without the need for specifying the 116.Fl ypset 117or 118.Fl ypsetme 119options, which are often considered to be security holes. The specified 120servers must have valid entries in the local 121.Pa /etc/hosts 122file. IP addresses may be specified in place of hostnames. If 123.Nm 124can't make sense ouf of the arguments, it will ignore 125the 126.Fl S 127flag and continue running normally. 128.Pp 129Note that 130.Nm 131will consider the domainname specified with the 132.Fl S 133flag to be the system default domain. 134.It Fl m 135Cause 136.Nm 137to use a 'many-cast' rather than a broadcast for choosing a server 138from the restricted mode server list. In many-cast mode, 139.Nm 140will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the 141servers specified in the restricted list and bind to the server that 142responds the fastest. 143This mode of operation is useful for NIS clients on remote subnets 144where no local NIS servers are available. The 145.Fl m 146flag can only be used in conjunction with the 147.Fl S 148flag above (if used without the 149.Fl S 150flag, it has no effect). 151.El 152.Sh NOTES 153The 154.Nm 155program will not make continuous attempts to keep secondary domains bound. 156If a server for a secondary domain fails to respond to a ping, 157.Nm 158will broadcast for a new server only once before giving up. If a 159client program attempts to reference the unbound domain, 160.Nm 161will try broadcasting again. By contrast, 162.Nm 163will automatically maintain a binding for the default domain whether 164client programs reference it ot not. 165.Sh FILES 166.Bl -tag -width /etc/rc.conf -compact 167.It Pa /var/yp/binding/[domainname].[version] 168the files used to hold binding information for each NIS domain 169.It Pa /etc/rc.conf 170system configuration file where the system default domain and 171ypbind startup options are specified 172.El 173.Sh SEE ALSO 174.Xr domainname 1 , 175.Xr syslog 3 , 176.Xr yp 4 , 177.Xr ypserv 8 , 178.Xr ypset 8 179.Sh AUTHORS 180.An Theo de Raadt Aq deraadt@fsa.ca 181