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diff --git a/chapter07/networkd.xml b/chapter07/networkd.xml new file mode 100644 index 000000000..86dcb3e53 --- /dev/null +++ b/chapter07/networkd.xml @@ -0,0 +1,270 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ + <!ENTITY % general-entities SYSTEM "../general.ent"> + %general-entities; +]> + +<sect1 id="ch-scripts-network"> + <?dbhtml filename="network.html"?> + + <title>General Network Configuration</title> + + <indexterm zone="ch-scripts-network"> + <primary sortas="d-network">network</primary> + <secondary>configuring</secondary></indexterm> + + <para>This section only applies if a network card is to be + configured.</para> + + <sect2> + <title>Network Interface Configuration Files</title> + + <para>Starting with version 209, systemd ships a network configuration + daemon called <command>systemd-networkd</command> which can be used for + basic network configuration. Additionally, since version 213, DNS name + resolution can be handled by <command>systemd-resolved</command> in place + of a static <filename>/etc/resolv.conf</filename> file. Both services are + enabled by defualt, and absolutely should not be disabled.</para> + + <para>Configuration files for <command>systemd-networkd</command> (and + <command>systemd-resolved</command>) can be placed in + <filename class="directory">/usr/lib/systemd/network</filename> + or <filename class="directory">/etc/systemd/network</filename>. Files in + <filename class="directory">/etc/systemd/network</filename> have a + higher priority than the ones in + <filename class="directory">/usr/lib/systemd/network</filename>. + There are three types of configuration files: + <filename class="extension">.link</filename>, + <filename class="extension">.netdev</filename> and + <filename class="extension">.network</filename> files. For detailed + descriptions and example contents of these configuration files, consult + the <filename>systemd-link(5)</filename>, + <filename>systemd-netdev(5)</filename> and + <filename>systemd-network(5)</filename> manual pages.</para> + + <note><para>Udev may assign network card interface names based + on system physical characteristics such as enp2s1. If you are + not sure what your interface name is, you can always run + <command>ip link</command> after you have booted your system. + </para></note> + + <sect3 id="systemd-networkd-static"> + <title>Static IP Configuration</title> + + <para>The command below creates a basic configuration file for a + Static IP setup (using both systemd-networkd and + systemd-resolved):</para> + +<screen role="nodump"><userinput>cat > /etc/systemd/network/10-eth0-static.network << "EOF" +<literal>[Match] +Name=eth0 + +[Network] +Address=192.168.0.2/24 +Gateway=192.168.0.1 +DNS=192.168.0.1 +Domains=<replaceable><Your Domain Name></replaceable></literal> +EOF</userinput></screen> + + <para>Multiple DNS entries can be added if you have more than one DNS + server. Do not include DNS or Domains entries if you intend to use a + static <filename>/etc/reslov.conf</filename> file.</para> + + </sect3> + + <sect3 id="systemd-networkd-dhcp"> + <title>DHCP Configuration</title> + + <para>The command below creates a basic configuration file for an IPv4 + DHCP setup:</para> + +<screen role="nodump"><userinput>cat > /etc/systemd/network/10-eth0-dhcp.network << "EOF" +<literal>[Match] +Name=eth0 + +[Network] +DHCP=ipv4 + +[DHCP] +UseDomains=true</literal> +EOF</userinput></screen> + + </sect3> + + </sect2> + + <sect2 id="resolv.conf"> + <title>Creating the /etc/resolv.conf File</title> + + <indexterm zone="resolv.conf"> + <primary sortas="e-/etc/resolv.conf">/etc/resolv.conf</primary> + </indexterm> + + <para>If the system is going to be connected to the Internet, it will + need some means of Domain Name Service (DNS) name resolution to + resolve Internet domain names to IP addresses, and vice versa. This is + best achieved by placing the IP address of the DNS server, available + from the ISP or network administrator, into + <filename>/etc/resolv.conf</filename>.</para> + + <sect3 id="resolv-conf-systemd-resoloved"> + <title>systemd-resolved Configuration</title> + + <note><para>If using another means to configure your network + interfaces (ex: ppp, network-manager, etc.), or if using any type of + local resolver (ex: bind, dnsmasq, etc.), or any other software that + generates an <filename>/etc/resolv.conf</filename> (ex: resolvconf), the + <command>systemd-resolved</command> service should not be + used.</para></note> + + <para>When using <command>systemd-resolved</command> for DNS + configuration, it is responsible for creating the + <filename>/etc/resolv.conf</filename> file. Since version 226, the + symlink for <filename>/etc/resolv.conf</filename> is created by systemd + when needed, so no further configuration is necessary.</para> + + </sect3> + + <sect3 id="resolv-conf-static"> + <title>Static resolv.conf Configuration</title> + + <para>If a static <filename>/etc/resolv.conf</filename> is desired, + create it by running the following command:</para> + +<screen role="nodump"><userinput>cat > /etc/resolv.conf << "EOF" +<literal># Begin /etc/resolv.conf + +domain <replaceable><Your Domain Name></replaceable> +nameserver <replaceable><IP address of your primary nameserver></replaceable> +nameserver <replaceable><IP address of your secondary nameserver></replaceable> + +# End /etc/resolv.conf</literal> +EOF</userinput></screen> + + <para>The <varname>domain</varname> statement can be omitted + or replaced with a <varname>search</varname> statement. See the man page + for resolv.conf for more details.</para> + + <para>Replace + <replaceable><IP address of the nameserver></replaceable> + with the IP address of the DNS most appropriate for the setup. There will + often be more than one entry (requirements demand secondary servers for + fallback capability). If you only need or want one DNS server, remove the + second <emphasis>nameserver</emphasis> line from the file. The IP address + may also be a router on the local network.</para> + + <note><para>The Google Public IPv4 DNS addresses are + <parameter>8.8.8.8</parameter> and <parameter>8.8.4.4</parameter> + for IPv4, and <parameter>2001:4860:4860::8888</parameter> and + <parameter>2001:4860:4860::8844</parameter> for IPv6.</para></note> + + </sect3> + + </sect2> + + <sect2 id="ch-scripts-hostname"> + <title>Configuring the system hostname</title> + + <indexterm zone="ch-scripts-hostname"> + <primary sortas="d-hostname">hostname</primary> + <secondary>configuring</secondary> + </indexterm> + + <para>During the boot process, the file <filename>/etc/hostname</filename> + is used for establishing the system's hostname.</para> + + <para>Create the <filename>/etc/hostname</filename> file and enter a + hostname by running:</para> + +<screen><userinput>echo "<replaceable><lfs></replaceable>" > /etc/hostname</userinput></screen> + + <para><replaceable><lfs></replaceable> needs to be replaced with the + name given to the computer. Do not enter the Fully Qualified Domain Name + (FQDN) here. That information is put in the + <filename>/etc/hosts</filename> file.</para> + + </sect2> + + <sect2 id="ch-scripts-hosts"> + <title>Customizing the /etc/hosts File</title> + + <indexterm zone="ch-scripts-hosts"> + <primary sortas="e-/etc/hosts">/etc/hosts</primary> + </indexterm> + + <indexterm zone="ch-scripts-hosts"> + <primary sortas="d-localnet">localnet</primary> + <secondary>/etc/hosts</secondary> + </indexterm> + + <indexterm zone="ch-scripts-hosts"> + <primary sortas="d-network">network</primary> + <secondary>/etc/hosts</secondary> + </indexterm> + + <para>Decide on a fully-qualified domain name (FQDN), and possible aliases + for use in the <filename>/etc/hosts</filename> file. If using static + addresses, you'll also need to decide on an IP address. The syntax + for a hosts file entry is:</para> + +<screen><literal>IP_address myhost.example.org aliases</literal></screen> + + <para>Unless the computer is to be visible to the Internet (i.e., there is + a registered domain and a valid block of assigned IP addresses—most + users do not have this), make sure that the IP address is in the private + network IP address range. Valid ranges are:</para> + +<screen><literal>Private Network Address Range Normal Prefix +10.0.0.1 - 10.255.255.254 8 +172.x.0.1 - 172.x.255.254 16 +192.168.y.1 - 192.168.y.254 24</literal></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>Even if not using a network card, a valid FQDN is still required. + This is necessary for certain programs to operate correctly.</para> + + <para>If using DHCP, DHCPv6, IPv6 Autoconfiguration, or if a network card + is not going to be configured, create the <filename>/etc/hosts</filename> + file by running the following command:</para> + +<screen><userinput>cat > /etc/hosts << "EOF" +<literal># Begin /etc/hosts + +127.0.0.1 <replaceable><HOSTNAME.example.org></replaceable> <replaceable><HOSTNAME></replaceable> localhost <replaceable>[alias1] [alias2] ...</replaceable> +::1 <replaceable><HOSTNAME.example.org></replaceable> <replaceable><HOSTNAME></replaceable> localhost <replaceable>[alias1] [alias2] ...</replaceable> + +# End /etc/hosts</literal> +EOF</userinput></screen> + + <para>The ::1 entry is the IPv6 counterpart of 127.0.0.1 and represents +the IPv6 loopback interface.</para> + + <para>If ussing a staic address, create the <filename>/etc/hosts</filename> + file by running this command instead:</para> + +<screen role="nodump"><userinput>cat > /etc/hosts << "EOF" +<literal># Begin /etc/hosts + +127.0.0.1 localhost +::1 localhost +<replaceable><192.168.0.2></replaceable> <replaceable><HOSTNAME.example.org></replaceable> <replaceable><HOSTNAME></replaceable> <replaceable>[alias1] [alias2] ...</replaceable> + +# End /etc/hosts</literal> +EOF</userinput></screen> + + <para>The <replaceable><192.168.0.2></replaceable>, + <replaceable><HOSTNAME.example.org></replaceable>, and + <replaceable><HOSTNAME></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.</para> + + </sect2> + +</sect1> |