1 | <?xml version="1.0" encoding="ISO-8859-1"?> |
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2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" |
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3 | "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [ |
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4 | <!ENTITY % general-entities SYSTEM "../../general.ent"> |
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5 | %general-entities; |
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6 | ]> |
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7 | |
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8 | <sect1 id="ch-scripts-network"> |
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9 | <?dbhtml filename="network.html"?> |
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10 | |
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11 | <title>Configuring the network Script</title> |
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12 | |
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13 | <indexterm zone="ch-scripts-network"> |
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14 | <primary sortas="d-network">network</primary> |
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15 | <secondary>configuring</secondary></indexterm> |
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16 | |
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17 | <para>This section only applies if a network card is to be |
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18 | configured.</para> |
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19 | |
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20 | <para>If a network card will not be used, there is likely no need to |
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21 | create any configuration files relating to network cards. If that is |
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22 | the case, remove the <filename class="symlink">network</filename> |
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23 | symlinks from all run-level directories (<filename |
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24 | class="directory">/etc/rc.d/rc*.d</filename>).</para> |
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25 | |
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26 | <sect2> |
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27 | <title>Creating Network Interface Configuration Files</title> |
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28 | |
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29 | <para>Which interfaces are brought up and down by the network script |
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30 | depends on the files and directories in the <filename |
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31 | class="directory">/etc/sysconfig/network-devices</filename> hierarchy. |
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32 | This directory should contain a sub-directory for each interface to be |
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33 | configured, such as <filename>ifconfig.xyz</filename>, where |
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34 | <quote>xyz</quote> is a network interface name. Inside this directory |
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35 | would be files defining the attributes to this interface, such as its |
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36 | IP address(es), subnet masks, and so forth.</para> |
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37 | |
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38 | <para>The following command creates a sample <filename>ipv4</filename> |
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39 | file for the <filename class="devicefile">eth0</filename> device:</para> |
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40 | |
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41 | <screen><userinput>cd /etc/sysconfig/network-devices && |
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42 | mkdir -v ifconfig.eth0 && |
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43 | cat > ifconfig.eth0/ipv4 << "EOF" |
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44 | <literal>ONBOOT=yes |
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45 | SERVICE=ipv4-static |
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46 | IP=192.168.1.1 |
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47 | GATEWAY=192.168.1.2 |
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48 | PREFIX=24 |
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49 | BROADCAST=192.168.1.255</literal> |
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50 | EOF</userinput></screen> |
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51 | |
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52 | <para>The values of these variables must be changed in every file to |
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53 | match the proper setup. If the <envar>ONBOOT</envar> variable is |
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54 | set to <quote>yes</quote> the network script will bring up the |
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55 | Network Interface Card (NIC) during booting of the system. If set |
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56 | to anything but <quote>yes</quote> the NIC will be ignored by the |
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57 | network script and not brought up.</para> |
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58 | |
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59 | <para>The <envar>SERVICE</envar> variable defines the method used for |
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60 | obtaining the IP address. The CLFS-Bootscripts package has a modular IP |
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61 | assignment format, and creating additional files in the <filename |
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62 | class="directory">/etc/sysconfig/network-devices/services</filename> |
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63 | directory allows other IP assignment methods. This is commonly used |
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64 | for Dynamic Host Configuration Protocol (DHCP), which is addressed in |
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65 | the BLFS book.</para> |
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66 | |
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67 | <para>The <envar>GATEWAY</envar> variable should contain the default |
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68 | gateway IP address, if one is present. If not, then comment out the |
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69 | variable entirely.</para> |
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70 | |
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71 | <para>The <envar>PREFIX</envar> variable needs to contain the number |
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72 | of bits used in the subnet. Each octet in an IP address is 8 bits. |
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73 | If the subnet's netmask is 255.255.255.0, then it is using the first |
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74 | three octets (24 bits) to specify the network number. If the netmask |
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75 | is 255.255.255.240, it would be using the first 28 bits. Prefixes |
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76 | longer than 24 bits are commonly used by DSL and cable-based Internet |
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77 | Service Providers (ISPs). In this example (PREFIX=24), the netmask is |
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78 | 255.255.255.0. Adjust the <envar>PREFIX</envar> variable according to |
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79 | your specific subnet.</para> |
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80 | |
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81 | </sect2> |
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82 | |
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83 | <sect2 id="resolv.conf"> |
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84 | <title>Creating the /etc/resolv.conf File</title> |
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85 | |
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86 | <indexterm zone="resolv.conf"> |
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87 | <primary sortas="e-/etc/resolv.conf">/etc/resolv.conf</primary> |
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88 | </indexterm> |
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89 | |
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90 | <para>If the system is going to be connected to the Internet, it will |
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91 | need some means of Domain Name Service (DNS) name resolution to resolve |
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92 | Internet domain names to IP addresses, and vice versa. This is best |
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93 | achieved by placing the IP address of the DNS server, available from |
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94 | the ISP or network administrator, into <filename>/etc/resolv.conf</filename>. |
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95 | Create the file by running the following:</para> |
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96 | |
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97 | <screen><userinput>cat > /etc/resolv.conf << "EOF" |
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98 | <literal># Begin /etc/resolv.conf |
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99 | |
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100 | domain {<replaceable>[Your Domain Name]</replaceable>} |
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101 | nameserver <replaceable>[IP address of your primary nameserver]</replaceable> |
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102 | nameserver <replaceable>[IP address of your secondary nameserver]</replaceable> |
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103 | |
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104 | # End /etc/resolv.conf</literal> |
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105 | EOF</userinput></screen> |
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106 | |
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107 | <para>Replace <replaceable>[IP address of the nameserver]</replaceable> |
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108 | with the IP address of the DNS most appropriate for the setup. There will |
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109 | often be more than one entry (requirements demand secondary servers for |
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110 | fallback capability). If you only need or want one DNS server, remove the |
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111 | second <emphasis>nameserver</emphasis> line from the file. The IP address |
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112 | may also be a router on the local network.</para> |
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113 | |
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114 | </sect2> |
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115 | |
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116 | </sect1> |
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