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\" @(#)hosts.5 8.2 (Berkeley) 12/11/93
\"
Dd November 17, 2000
Dt HOSTS 5
Os
Sh NAME
Nm hosts
Nd host name data base
Sh DESCRIPTION
The
Nm hosts
file contains information regarding the known hosts on the network.
It can be used in conjunction with the DNS, and the
Tn NIS
maps
Sq hosts.byaddr ,
and
Sq hosts.byname ,
as controlled by
Xr nsswitch.conf 5 .
Pp
For each host a single line should be present
with the following information:
Dl address hostname [alias ...]
Pp
These are:
Bl -tag -width hostname -compact -offset indent
It Em address
Internet address
It Em hostname
Official host name
It Em alias
Alias host name
El
Pp
Items are separated by any number of blanks and/or
tab characters. A hash sign
Pq Dq \&#
indicates the beginning of
a comment; characters up to the end of the line are
not interpreted by routines which search the file.
Pp
When using the name server
Xr named 8 ,
or
Xr 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
Xr ifconfig 8
needs at boot time and a few machines on the local network.
Pp
As network addresses, both IPv4 and IPv6 addresses are allowed.
IPv4 addresses are specified in the conventional dot
Pq Dq \&.
notation using the
Xr inet_pton 3
routine
from the Internet address manipulation library,
Xr 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.
Sh FILES
Bl -tag -width /etc/hosts -compact
It Pa /etc/hosts
The
Nm hosts
file resides in
Pa /etc .
El
Sh SEE ALSO
Xr gethostbyname 3 ,
Xr nsswitch.conf 5 ,
Xr ifconfig 8 ,
Xr named 8
Rs
%T "Name Server Operations Guide for BIND"
Re
Sh HISTORY
The
Nm
file format appeared in
Bx 4.2 .
