1.\" Copyright (c) 1983, 1991, 1993 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.\" @(#)hosts.5 8.2 (Berkeley) 12/11/93 33.\" $FreeBSD$ 34.\" 35.Dd December 11, 1993 36.Dt HOSTS 5 37.Os BSD 4.2 38.Sh NAME 39.Nm hosts 40.Nd host name data base 41.Sh DESCRIPTION 42The 43.Nm hosts 44file contains information regarding 45the known hosts on the network. 46For each host a single line should be present 47with the following information: 48.Bd -unfilled -offset indent 49Internet address 50official host name 51aliases 52.Ed 53.Pp 54Items are separated by any number of blanks and/or 55tab characters. A ``#'' indicates the beginning of 56a comment; characters up to the end of the line are 57not interpreted by routines which search the file. 58.Pp 59When using the name server 60.Xr named 8 , 61this file provides a backup used when the name server 62is not running. 63For the name server, it is suggested that only a few addresses 64be included in this file. 65These include addresses for the local interfaces that 66.Xr ifconfig 8 67needs at boot time and a few machines on the local network. 68.Pp 69This file may be created from the official host 70data base maintained at the Network Information Control 71Center 72.Pq Tn NIC , 73though local changes may be required 74to bring it up to date regarding unofficial aliases 75and/or unknown hosts. As the data base maintained at 76.Tn NIC 77is incomplete, use of the name server is recommended for 78sites on the 79.Tn DARPA 80Internet. 81.Pp 82Network addresses are specified in the conventional 83``.'' (dot) notation using the 84.Xr inet_addr 3 85routine 86from the Internet address manipulation library, 87.Xr inet 3 . 88Host names may contain any printable 89character other than a field delimiter, newline, 90or comment character. 91.Sh FILES 92.Bl -tag -width /etc/hosts -compact 93.It Pa /etc/hosts 94The 95.Nm hosts 96file resides in 97.Pa /etc . 98.El 99.Sh SEE ALSO 100.Xr gethostbyname 3 , 101.Xr ifconfig 8 , 102.Xr named 8 103.Rs 104.%T "Name Server Operations Guide for BIND" 105.Re 106.Sh HISTORY 107The 108.Nm 109file format appeared in 110.Bx 4.2 . 111