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hosts(5) [freebsd man page]

HOSTS(5)						      BSD File Formats Manual							  HOSTS(5)

NAME
hosts -- host name data base DESCRIPTION
The hosts file contains information regarding the known hosts on the network. It can be used in conjunction with DNS, and the NIS maps `hosts.byaddr' and `hosts.byname', as controlled by nsswitch.conf(5). For each host a single line should be present with the following information: Internet address official host name aliases Items are separated by any number of blanks and/or tab characters. A ``#'' indicates the beginning of a comment; characters up to the end of the line are not interpreted by routines which search the file. This file provides a backup used when the name server is not running. For the name server, it is suggested that only a few addresses be included in this file. These include addresses for the local interfaces that ifconfig(8) needs at boot time and a few machines on the local network. This file may be created from the official host data base maintained at the Network Information Control Center (NIC), though local changes may be required to bring it up to date regarding unofficial aliases and/or unknown hosts. As the data base maintained at NIC is incomplete, use of the name server is recommended for sites on the DARPA Internet. Network addresses are specified in the conventional ``.'' (dot) notation using the inet_addr(3) routine from the Internet address manipula- tion library, inet(3). Host names may contain any printable character other than a field delimiter, newline, or comment character. FILES
/etc/hosts The hosts file resides in /etc. SEE ALSO
gethostbyname(3), nsswitch.conf(5), ifconfig(8) Name Server Operations Guide for BIND. HISTORY
The hosts file format appeared in 4.2BSD. BSD
December 25, 2013 BSD

Check Out this Related Man Page

HOSTS(5)						      Debian GNU/Linux manual							  HOSTS(5)

NAME
hosts - The static table lookup for host names SYNOPSIS
/etc/hosts DESCRIPTION
This manual page describes the format of the /etc/hosts file. This file is a simple text file that associates IP addresses with hostnames, one line per IP address. For each host a single line should be present with the following information: IP_address canonical_hostname aliases Fields of the entry are separated by any number of blanks and/or tab characters. Text from a "#" character until the end of the line is a comment, and is ignored. Host names may contain only alphanumeric characters, minus signs ("-"), and periods ("."). They must begin with an alphabetic character and end with an alphanumeric character. Aliases provide for name changes, alternate spellings, shorter hostnames, or generic hostnames (for example, localhost). The format of the host table is described in RFC 952. The Berkeley Internet Name Domain (BIND) Server implements the Internet name server for UNIX systems. It augments or replaces the /etc/hosts file or host name lookup, and frees a host from relying on /etc/hosts being up to date and complete. In modern systems, even though the host table has been superseded by DNS, it is still widely used for: bootstrapping Most systems have a small host table containing the name and address information for important hosts on the local network. This is useful when DNS is not running, for example during system bootup. NIS Sites that use NIS use the host table as input to the NIS host database. Even though NIS can be used with DNS, most NIS sites still use the host table with an entry for all local hosts as a backup. isolated nodes Very small sites that are isolated from the network use the host table instead of DNS. If the local information rarely changes, and the network is not connected to the Internet, DNS offers little advantage. EXAMPLE
127.0.0.1 localhost 192.168.1.10 foo.mydomain.org foo 192.168.1.13 bar.mydomain.org bar 216.234.231.5 master.debian.org master 205.230.163.103 www.opensource.org HISTORICAL NOTE
Before the advent of DNS, the host table was the only way of resolving hostnames on the fledgling Internet. Indeed, this file could be cre- ated from the official host data base maintained at the Network Information Control Center (NIC), though local changes were often required to bring it up to date regarding unofficial aliases and/or unknown hosts. The NIC no longer maintains the hosts.txt files, though looking around at the time of writing (circa 2000), there are historical hosts.txt files on the WWW. I just found three, from 92, 94, and 95. FILES
/etc/hosts SEE ALSO
hostname(1) resolver(3), resolver(5), hosts(5), hostname(7), named(8), Internet RFC 952 AUTHOR
This manual page was written by Manoj Srivastava <srivasta@debian.org>, for the Debian GNU/Linux system. Debian 2002-06-16 HOSTS(5)

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