hosts(4)

DESCRIPTION

The file /etc/hosts associates Internet (IP) addresses with official host names and aliases. This allows a user to refer to a host by a symbolic name instead of an Internet address.

Note: This file must contain all addresses for local interfaces that ifconfig needs at boot time (see ifconfig(1M)). When using the name server (see named(1M)), or Network Information Service (see ypserv(1M)), this file often serves as a backup when the server is not running. In such circumstances, it is a common practice for /etc/hosts to contain a few addresses of machines on the local network.

/etc/hosts should contain a single line for each host with the following information:

Aliases are other names by which a host is known. They can substitute for the official host name in most commands. For example:

In this example, users can use remote login on hpdxsg by using the command:

instead of

If your system is in a domain naming environment, an official host name consists of the full domain extended host name. For example:

A line cannot start with a blank (space or tab character). Items are separated by any number or combination of space or tab characters (blanks). A # character indicates the beginning of a comment. Characters from the # to the end of the line are not interpreted by routines that search the file. Trailing blanks are allowed at the end of a line.

For the Internet, this file is normally created from the official host database maintained at the Network Information Control Center (NIC), although local changes may be required to bring it up to date with respect to unofficial aliases and/or unknown hosts.

Network addresses are specified in the conventional Internet dot notation using the inet_addr() routine from the Internet address manipulation library (see inet(3N)). Host names can contain any printable character other than a white space, newline, or comment character.

EXAMPLES

See /etc/hosts.

AUTHOR

hosts was developed by the University of California, Berkeley.

SEE ALSO

gethostent(3N), inet(3N), nsswitch.conf(4).