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authorXi Ruoyao <xry111@xry111.site>2023-12-05 13:12:55 +0800
committerXi Ruoyao <xry111@xry111.site>2023-12-05 13:12:55 +0800
commit73d91ac621a4e59f71ff6664c68c935317f9ce42 (patch)
tree4f9b341370b83d97379a1343a69d13d48cb65740 /chapter09/networkd.xml
parent6b6a1b958af3a0e59559e44ad700f761d8a49a09 (diff)
parentdc8572f2413a4d25444bb1237ea2a01dfba60429 (diff)
Merge remote-tracking branch 'origin/trunk' into xry111/arm64
Diffstat (limited to 'chapter09/networkd.xml')
-rw-r--r--chapter09/networkd.xml53
1 files changed, 24 insertions, 29 deletions
diff --git a/chapter09/networkd.xml b/chapter09/networkd.xml
index 43b7e7172..27f15e815 100644
--- a/chapter09/networkd.xml
+++ b/chapter09/networkd.xml
@@ -316,27 +316,18 @@ EOF</userinput></screen>
<para>x can be any number in the range 16-31. y can be any number in the
range 0-255.</para>
- <para>A valid private IP address could be 192.168.1.1. A valid FQDN for
- this IP could be lfs.example.org.</para>
+ <para>A valid private IP address could be 192.168.1.1.</para>
- <para>Even if not using a network card, a valid FQDN is still required.
- This is necessary for certain programs, such as MTAs, to operate properly.</para>
+ <para>If the computer is to be visible to the Internet, a valid FQDN
+ can be the domain name itself, or a string resulted by concatenating a
+ prefix (often the hostname) and the domain name with a <quote>.</quote>
+ character. And, you need to contact the domain provider to resolve the
+ FQDN to your public IP address.</para>
-<!--
- <para>Create the /etc/hosts file using the following command:</para>
-
-<screen role="nodump"><userinput>cat &gt; /etc/hosts &lt;&lt; "EOF"
-<literal># Begin /etc/hosts
-
-127.0.0.1 localhost.localdomain localhost
-127.0.1.1 <replaceable>&lt;FQDN&gt;</replaceable> <replaceable>&lt;HOSTNAME&gt;</replaceable>
-::1 localhost ip6-localhost ip6-loopback
-ff02::1 ip6-allnodes
-ff02::2 ip6-allrouters
-
-# End /etc/hosts</literal>
-EOF</userinput></screen>
--->
+ <para>Even if the computer is not visible to the Internet, a FQDN is
+ still needed for certain programs, such as MTAs, to operate properly.
+ A special FQDN, <literal>localhost.localdomain</literal>, can be used
+ for this purpose.</para>
<para>Create the <filename>/etc/hosts</filename> file using the following
command:</para>
@@ -344,28 +335,32 @@ EOF</userinput></screen>
<screen><userinput>cat &gt; /etc/hosts &lt;&lt; "EOF"
<literal># Begin /etc/hosts
-127.0.0.1 localhost.localdomain localhost
-127.0.1.1 <replaceable>&lt;FQDN&gt;</replaceable> <replaceable>&lt;HOSTNAME&gt;</replaceable>
-<replaceable>&lt;192.168.0.2&gt;</replaceable> <replaceable>&lt;FQDN&gt;</replaceable> <replaceable>&lt;HOSTNAME&gt;</replaceable> <replaceable>[alias1] [alias2] ...</replaceable>
-::1 localhost ip6-localhost ip6-loopback
+<replaceable>&lt;192.168.0.2&gt;</replaceable> <replaceable>&lt;FQDN&gt;</replaceable> <replaceable>[alias1] [alias2] ...</replaceable>
+::1 ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
# End /etc/hosts</literal>
EOF</userinput></screen>
- <para>The <replaceable>&lt;192.168.0.2&gt;</replaceable>,
- <replaceable>&lt;FQDN&gt;</replaceable>, and
- <replaceable>&lt;HOSTNAME&gt;</replaceable> values need to be
+ <para>The <replaceable>&lt;192.168.0.2&gt;</replaceable> and
+ <replaceable>&lt;FQDN&gt;</replaceable> values need to be
changed for specific uses or requirements (if assigned an IP address by a
network/system administrator and the machine will be connected to an
existing network). The optional alias name(s) can be omitted, and the
<replaceable>&lt;192.168.0.2&gt;</replaceable> line can be omitted if you
- are using a connection configured with DHCP or IPv6 Autoconfiguration.</para>
+ are using a connection configured with DHCP or IPv6 Autoconfiguration,
+ or using <literal>localhost.localdomain</literal> as the FQDN.</para>
+
+ <para>The <filename>/etc/hostname</filename> does not contain entries
+ for <literal>localhost</literal>,
+ <literal>localhost.localdomain</literal>, or the hostname (without a
+ domain) because they are handled by the
+ <systemitem class='library'>myhostname</systemitem> NSS module, read
+ the man page <filename>nss-myhostname(8)</filename> for details.</para>
<para>The ::1 entry is the IPv6 counterpart of 127.0.0.1 and represents
- the IPv6 loopback interface. 127.0.1.1 is a loopback entry reserved
- specifically for the FQDN.</para>
+ the IPv6 loopback interface.</para>
</sect2>