1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.roff% 5.\" 6.\" @(#)hosts.5 8.2 (Berkeley) 12/11/93 7.\" 8.Dd 9.Dt HOSTS 5 10.Os BSD 4.2 11.Sh NAME 12.Nm hosts 13.Nd host name data base 14.Sh DESCRIPTION 15The 16.Nm hosts 17file contains information regarding 18the known hosts on the network. 19For each host a single line should be present 20with the following information: 21.Bd -unfilled -offset indent 22official host name 23Internet address 24aliases 25.Ed 26.Pp 27Items are separated by any number of blanks and/or 28tab characters. A ``#'' indicates the beginning of 29a comment; characters up to the end of the line are 30not interpreted by routines which search the file. 31.Pp 32When using the name server 33.Xr named 8 , 34this file provides a backup when the name server 35is not running. 36For the name server, it is suggested that only a few addresses 37be included in this file. 38These include address for the local interfaces that 39.Xr ifconfig 8 40needs at boot time and a few machines on the local network. 41.Pp 42This file may be created from the official host 43data base maintained at the Network Information Control 44Center 45.Pq Tn NIC , 46though local changes may be required 47to bring it up to date regarding unofficial aliases 48and/or unknown hosts. As the data base maintained at 49.Tn NIC 50is incomplete, use of the name server is recommended for 51sites on the 52.Tn DARPA 53Internet. 54.Pp 55Network addresses are specified in the conventional 56``.'' (dot) notation using the 57.Xr inet_addr 3 58routine 59from the Internet address manipulation library, 60.Xr inet 3 . 61Host names may contain any printable 62character other than a field delimiter, newline, 63or comment character. 64.Sh FILES 65.Bl -tag -width /etc/hosts -compact 66.It Pa /etc/hosts 67The 68.Nm hosts 69file resides in 70.Pa /etc . 71.El 72.Sh SEE ALSO 73.Xr gethostbyname 3 , 74.Xr ifconfig 8 , 75.Xr named 8 76.Rs 77.%T "Name Server Operations Guide for BIND" 78.Re 79.Sh HISTORY 80The 81.Nm 82file format appeared in 83.Bx 4.2 . 84