source: BOOK/network/common/hosts.xml @ 1902d37

systemd
Last change on this file since 1902d37 was 1902d37, checked in by William Harrington <kb0iic@…>, 5 years ago

Add IPv6 localhost entry to /etc/hosts and add text about it.

  • Property mode set to 100644
File size: 3.3 KB
RevLine 
[3f8be484]1<?xml version="1.0" encoding="ISO-8859-1"?>
[aa18ac0]2<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
[0b9e109]4  <!ENTITY % general-entities SYSTEM "../../general.ent">
[3f8be484]5  %general-entities;
6]>
7
[0b9e109]8<sect1 id="ch-network-hosts">
[3f8be484]9  <?dbhtml filename="hosts.html"?>
10
[8a74dc5]11  <title>Customizing the /etc/hosts File</title>
[3f8be484]12
[0b9e109]13  <indexterm zone="ch-network-hosts">
[3f8be484]14    <primary sortas="e-/etc/hosts">/etc/hosts</primary>
15  </indexterm>
16
[0b9e109]17  <indexterm zone="ch-network-hosts">
[3f8be484]18    <primary sortas="d-localnet">localnet</primary>
19  <secondary>/etc/hosts</secondary></indexterm>
20
[0b9e109]21  <indexterm zone="ch-network-hosts">
[3f8be484]22    <primary sortas="d-network">network</primary>
23  <secondary>/etc/hosts</secondary></indexterm>
24
25  <para>If a network card is to be configured, decide on the IP address,
[99f8c39]26  fully-qualified domain name (FQDN), and possible aliases for use in the
[3f8be484]27  <filename>/etc/hosts</filename> file. The syntax is:</para>
28
29  <screen>&lt;IP address&gt; myhost.example.org aliases</screen>
30
31  <para>Unless the computer is to be visible to the Internet (i.e.,
32  there is a registered domain and a valid block of assigned IP
33  addresses&mdash;most users do not have this), make sure that the IP
34  address is in the private network IP address range. Valid ranges
35  are:</para>
36
[99f8c39]37<screen><literal>Private Network Address Range       Normal Prefix
3810.0.0.1 - 10.255.255.254           8
39172.x.0.1 - 172.x.255.254           16
40192.168.y.1 - 192.168.y.254         24</literal></screen>
41
42  <para>x can be any number in the range 16-31. y can be any number in the
43  range 0-255.</para>
[3f8be484]44
45  <para>A valid IP address could be 192.168.1.1. A valid FQDN for this
[e318995]46  IP could be <uri>www.clfs.org</uri> (not recommended
[3f8be484]47  because this is a valid registered domain address and could cause
48  domain name server issues).</para>
49
[99f8c39]50  <para>Even if not using a network card, a valid FQDN is still required.
[3f8be484]51  This is necessary for certain programs to operate correctly.</para>
52
[99f8c39]53  <para>Create the <filename>/etc/hosts</filename> file by running:</para>
[3f8be484]54
[1ecf563]55<screen role="nodump"><userinput>cat &gt; /etc/hosts &lt;&lt; "EOF"
[3f8be484]56<literal># Begin /etc/hosts (network card version)
57
58127.0.0.1 localhost
[1902d37]59::1       localhost
[99f8c39]60<replaceable>[192.168.1.1]</replaceable> <replaceable>[&lt;HOSTNAME&gt;.example.org]</replaceable> <replaceable>[HOSTNAME]</replaceable> <replaceable>[alias ...]</replaceable>
[3f8be484]61
62# End /etc/hosts (network card version)</literal>
63EOF</userinput></screen>
64
65  <para>The <replaceable>[192.168.1.1]</replaceable> and
66  <replaceable>[&lt;HOSTNAME&gt;.example.org]</replaceable>
67  values need to be changed for specific users or requirements (if
68  assigned an IP address by a network/system administrator and the
[99f8c39]69  machine will be connected to an existing network). The optional
70  alias name(s) can be omitted.</para>
[3f8be484]71
72  <para>If a network card is not going to be configured, create the
73  <filename>/etc/hosts</filename> file by running:</para>
74
[1ecf563]75<screen role="nodump"><userinput>cat &gt; /etc/hosts &lt;&lt; "EOF"
[3f8be484]76<literal># Begin /etc/hosts (no network card version)
77
78127.0.0.1 <replaceable>[&lt;HOSTNAME&gt;.example.org]</replaceable> <replaceable>[HOSTNAME]</replaceable> localhost
[1902d37]79::1       localhost
[3f8be484]80
81# End /etc/hosts (no network card version)</literal>
82EOF</userinput></screen>
83
[1902d37]84<para>The ::1 entry is the IPv6 counterpart of 127.0.0.1 and represents the
85      IPv6 loopback interface.</para>
86
[3f8be484]87</sect1>
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