calmsacibis995
91 lines
2.4 KiB
Plaintext
91 lines
2.4 KiB
Plaintext
.\" Copyright (c) 1983 Regents of the University of California.
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.\" All rights reserved. The Berkeley software License Agreement
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.\" specifies the terms and conditions for redistribution.
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.\"
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.\" @(#)hosts.5 6.3 (Berkeley) 5/14/86
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.\"
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.TH hosts 4
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.SH NAME
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hosts \- hostname-address database
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.SH DESCRIPTION
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The
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.I /etc/hosts
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file contains information regarding
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the known hosts on the network.
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For each host a single line should be present
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with the following information:
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.RS
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.IP \(bu 3
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Internet address
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.IP \(bu 3
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official hostname
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.IP \(bu 3
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aliases (optional)
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.RE
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.PP
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Items are separated by any number of blanks and/or
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tab characters.
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A \f3#\f1 indicates the beginning of
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a comment; characters up to the end of the line are
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not interpreted by routines that search the file.
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For example,
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.Ex
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192.0.2.2 iris.widgets.com iris
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.Ee
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This file must include entries for all of the machine's network interfaces,
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the localhost address
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and a few important machines on the local network.
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.IR ifconfig (1M)
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uses this file when assigning addresses to the network interfaces
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during system initialization.
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.P
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By default, this file is used by
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.IR gethostbyname (3N)
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and
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.IR gethostbyaddr (3N)
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only when the NIS or
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the Berkeley Internet name server
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.RI ( named (1M))
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are not enabled.
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The system can be configured to use NIS,
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.IR named ,
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and/or this file, as described in
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.IR resolver (4).
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.PP
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If the host is not connected to any network, the file
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should contain an entry defining the hostname as an
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alias for the localhost entry.
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For example, if the hostname is IRIS, the
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.I /etc/hosts
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file should contain this line:
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.Ex
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127.1 localhost IRIS
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.Ee
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Sites connected to the Internet should configure the system
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to use the name server.
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This file can be created from the official host
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database maintained at the Network Information
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Center (NIC), though local changes may be required
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to bring it up to date regarding unofficial aliases
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and/or unknown hosts.
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The host database maintained at NIC
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is incomplete.
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.PP
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Network addresses are specified in the conventional
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dot (.) notation using the \f2inet_addr\fP() routine
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from the Internet address manipulation library,
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.IR inet (3N).
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Legal hostnames can contain any alphanumeric
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character, the minus sign (\-) and period (.).
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Periods are not part of the name but serve to separate components
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of a domain-style name.
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.SH FILES
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/etc/hosts
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.SH "SEE ALSO"
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ifconfig(1M),
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named(1M),
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gethostbyname(3N),
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resolver(4),
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sys_id(4),
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hostname(5).
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