HOSTS(5) | 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 the 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:

`address hostname [alias ...]`

These are:

address
  Internet address
hostname
  Official host name
alias
  Alias host name

Items are separated by any number of blanks and/or tab characters. A hash sign (“#”) indicates the beginning of a comment; characters up to the end of the line are not interpreted by routines which search the file.

When using the name server named(8), or ypserv(8), this file provides a backup 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 address for the local interfaces that ifconfig(8) needs at boot time and a few machines on the local network.

As network addresses, both IPv4 and IPv6 addresses are allowed. IPv4 addresses are specified in the conventional dot (“.”) notation using the inet_pton(3) routine from the Internet address manipulation library, inet(3). IPv6 addresses are specified in the standard hex-and-colon notation. 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), named(8)

Name Server Operations Guide for BIND.

# HISTORY

The `hosts` file format appeared in 4.2BSD.

November 17, 2000 | NetBSD 11.0