1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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3 | "http://www.oasis-open.org/docbook/xml/4.5/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 | <!ENTITY iptables-download-http "http://www.netfilter.org/projects/iptables/files/iptables-&iptables-version;.tar.bz2">
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8 | <!ENTITY iptables-download-ftp "ftp://ftp.netfilter.org/pub/iptables/iptables-&iptables-version;.tar.bz2">
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9 | <!ENTITY iptables-md5sum "0a9209f928002e5eee9cdff8fef4d4b3">
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10 | <!ENTITY iptables-size "169 KB">
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11 | <!ENTITY iptables-buildsize "4.0 MB">
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12 | <!ENTITY iptables-time "0.1 SBU">
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13 | ]>
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14 |
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15 | <sect1 id="iptables" xreflabel="iptables-&iptables-version;">
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16 | <?dbhtml filename="iptables.html"?>
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17 |
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18 | <sect1info>
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19 | <othername>$LastChangedBy$</othername>
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20 | <date>$Date$</date>
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21 | </sect1info>
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22 |
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23 | <title>Iptables-&iptables-version;</title>
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24 |
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25 | <indexterm zone="iptables">
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26 | <primary sortas="a-Iptables">Iptables</primary>
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27 | </indexterm>
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28 |
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29 | <sect2 role="package">
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30 | <title>Introduction to Iptables</title>
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31 |
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32 | <para>The next part of this chapter deals with firewalls. The principal
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33 | firewall tool for Linux, as of the 2.4 kernel series, is
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34 | <application>iptables</application>. It replaces
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35 | <application>ipchains</application> from the 2.2 series and
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36 | <application>ipfwadm</application> from the 2.0 series. You will need to
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37 | install <application>iptables</application> if you intend on using any
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38 | form of a firewall.</para>
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39 |
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40 | <bridgehead renderas="sect3">Package Information</bridgehead>
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41 | <itemizedlist spacing="compact">
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42 | <listitem>
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43 | <para>Download (HTTP): <ulink url="&iptables-download-http;"/></para>
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44 | </listitem>
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45 | <listitem>
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46 | <para>Download (FTP): <ulink url="&iptables-download-ftp;"/></para>
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47 | </listitem>
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48 | <listitem>
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49 | <para>Download MD5 sum: &iptables-md5sum;</para>
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50 | </listitem>
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51 | <listitem>
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52 | <para>Download size: &iptables-size;</para>
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53 | </listitem>
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54 | <listitem>
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55 | <para>Estimated disk space required: &iptables-buildsize;</para>
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56 | </listitem>
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57 | <listitem>
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58 | <para>Estimated build time: &iptables-time;</para>
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59 | </listitem>
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60 | </itemizedlist>
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61 |
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62 | <para condition="html" role="usernotes">User Notes:
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63 | <ulink url="&blfs-wiki;/iptables"/></para>
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64 |
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65 | </sect2>
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66 |
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67 | <sect2 role="kernel" id='iptables-kernel'>
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68 | <title>Kernel Configuration</title>
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69 |
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70 | <para>A firewall in Linux is accomplished through a portion of the
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71 | kernel called netfilter. The interface to netfilter is
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72 | <application>iptables</application>. To use it, the appropriate
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73 | kernel configuration parameters are found in Networking ⇒
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74 | Networking Options ⇒ Network Packet Filtering ⇒
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75 | Core Netfilter Configuration (and) IP: Netfilter Configuration.</para>
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76 |
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77 | <indexterm zone="iptables iptables-kernel">
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78 | <primary sortas="d-iptables">Iptables</primary>
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79 | </indexterm>
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80 |
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81 | </sect2>
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82 |
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83 | <sect2 role="installation">
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84 | <title>Installation of Iptables</title>
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85 |
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86 | <note>
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87 | <para>The installation below does not include building some specialized
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88 | extension libraries which require the raw headers in the
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89 | <application>Linux</application> source code. If you wish to build the
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90 | additional extensions (if you aren't sure, then you probably don't), you
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91 | can look at the <filename>INSTALL</filename> file to see an example of
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92 | how to change the <parameter>KERNEL_DIR=</parameter> parameter to point
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93 | at the <application>Linux</application> source code. Note that if you
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94 | upgrade the kernel version, you may also need to recompile
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95 | <application>iptables</application> and that the BLFS team has not tested
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96 | using the raw kernel headers.</para>
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97 |
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98 | <!-- <para>Installation of <application>iptables</application> will fail
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99 | if raw kernel headers are found in <filename
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100 | class='directory'>/usr/src/linux</filename> either as actual files
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101 | or a symlink. As of the Linux 2.6 kernel series, this directory
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102 | should no longer exist because appropriate headers were installed
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103 | from the <application>Linux-Libc-Headers</application> package during
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104 | the base LFS installation.</para> -->
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105 |
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106 | <para>For some non-x86 architectures, the raw kernel headers may be
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107 | required. In that case, modify the <parameter>KERNEL_DIR=</parameter>
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108 | parameter to point at the <application>Linux</application> source
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109 | code.</para>
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110 | </note>
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111 |
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112 | <para>Install <application>iptables</application> by running the following
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113 | commands:</para>
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114 |
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115 | <screen><userinput>sed -i 's/name="$node/name="node/' iptables.xslt &&
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116 | make LIBDIR=/lib KERNEL_DIR=/usr</userinput></screen>
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117 |
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118 | <para>This package does not come with a test suite.</para>
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119 |
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120 | <para>Now, as the <systemitem class="username">root</systemitem> user:</para>
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121 |
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122 | <screen role="root"><userinput>make PREFIX=/usr LIBDIR=/lib BINDIR=/sbin \
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123 | MANDIR=/usr/share/man install &&
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124 | install -v -m644 iptables.xslt /lib/iptables</userinput></screen>
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125 |
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126 | </sect2>
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127 |
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128 | <sect2 role="commands">
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129 | <title>Command Explanations</title>
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130 |
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131 | <para><command>sed -i 's/name="$node/name="node/' iptables.xslt</command>:
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132 | This corrects a syntax error in the XSLT stylesheet for use with
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133 | <command>iptables-xml</command>.</para>
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134 |
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135 | <para><parameter>PREFIX=/usr LIBDIR=/lib BINDIR=/sbin</parameter>:
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136 | Compiles and installs <application>iptables</application> modules
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137 | into <filename class="directory">/lib</filename>, binaries into
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138 | <filename class="directory">/sbin</filename> and the remainder into
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139 | the <filename class="directory">/usr</filename> hierarchy instead of
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140 | <filename class="directory">/usr/local</filename>. Firewalls are
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141 | generally activated during the boot process and
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142 | <filename class="directory">/usr</filename> may not be mounted at
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143 | that time.</para>
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144 |
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145 | <para><parameter>KERNEL_DIR=/usr</parameter>: This parameter is used to
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146 | point at the sanitized kernel headers in
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147 | <filename class='directory'>/usr</filename> and not use the raw kernel
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148 | headers in <filename class='directory'>/usr/src/linux</filename>.</para>
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149 |
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150 | </sect2>
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151 |
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152 | <sect2 role="configuration">
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153 | <title>Configuring Iptables</title>
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154 |
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155 | <para>Introductory instructions for configuring your firewall are
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156 | presented in the next section: <xref linkend='fw-firewall'/></para>
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157 |
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158 | <sect3 id="iptables-init">
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159 | <title>Boot Script</title>
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160 |
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161 | <para>To set up the iptables firewall at boot, install the
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162 | <filename>/etc/rc.d/init.d/iptables</filename> init script included
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163 | in the <xref linkend="bootscripts"/> package.</para>
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164 |
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165 | <indexterm zone="iptables iptables-init">
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166 | <primary sortas="f-iptables">iptables</primary>
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167 | </indexterm>
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168 |
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169 | <screen role="root"><userinput>make install-iptables</userinput></screen>
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170 |
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171 | </sect3>
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172 |
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173 | </sect2>
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174 |
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175 | <sect2 role="content">
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176 | <title>Contents</title>
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177 |
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178 | <segmentedlist>
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179 | <segtitle>Installed Programs</segtitle>
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180 | <segtitle>Installed Libraries</segtitle>
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181 | <segtitle>Installed Directory</segtitle>
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182 |
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183 | <seglistitem>
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184 | <seg>iptables, iptables-restore, iptables-save, iptables-xml and
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185 | ip6tables</seg>
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186 | <seg>libip6t_*.so and libipt_*.so</seg>
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187 | <seg>/lib/iptables</seg>
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188 | </seglistitem>
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189 | </segmentedlist>
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190 |
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191 | <variablelist>
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192 | <bridgehead renderas="sect3">Short Descriptions</bridgehead>
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193 | <?dbfo list-presentation="list"?>
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194 | <?dbhtml list-presentation="table"?>
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195 |
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196 | <varlistentry id="iptables-prog">
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197 | <term><command>iptables</command></term>
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198 | <listitem>
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199 | <para>is used to set up, maintain, and inspect the tables of
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200 | IP packet filter rules in the Linux kernel.</para>
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201 | <indexterm zone="iptables iptables-prog">
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202 | <primary sortas="b-iptables">iptables</primary>
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203 | </indexterm>
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204 | </listitem>
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205 | </varlistentry>
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206 |
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207 | <varlistentry id="iptables-restore">
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208 | <term><command>iptables-restore</command></term>
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209 | <listitem>
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210 | <para>is used to restore IP Tables from data
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211 | specified on STDIN. Use I/O redirection provided by your
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212 | shell to read from a file.</para>
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213 | <indexterm zone="iptables iptables-restore">
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214 | <primary sortas="b-iptables-restore">iptables-restore</primary>
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215 | </indexterm>
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216 | </listitem>
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217 | </varlistentry>
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218 |
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219 | <varlistentry id="iptables-save">
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220 | <term><command>iptables-save</command></term>
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221 | <listitem>
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222 | <para>is used to dump the contents of an IP Table
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223 | in easily parseable format to STDOUT. Use I/O-redirection
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224 | provided by your shell to write to a file.</para>
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225 | <indexterm zone="iptables iptables-save">
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226 | <primary sortas="b-iptables-save">iptables-save</primary>
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227 | </indexterm>
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228 | </listitem>
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229 | </varlistentry>
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230 |
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231 | <varlistentry id="iptables-xml">
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232 | <term><command>iptables-xml</command></term>
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233 | <listitem>
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234 | <para>is used to convert the output of
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235 | <command>iptables-save</command> to an XML format. Using the
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236 | <filename>iptables.xslt</filename> stylesheet converts the XML
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237 | back to the format of <command>iptables-restore</command>.</para>
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238 | <indexterm zone="iptables iptables-xml">
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239 | <primary sortas="b-iptables-xml">iptables-xml</primary>
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240 | </indexterm>
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241 | </listitem>
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242 | </varlistentry>
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243 |
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244 | <varlistentry id="ip6tables">
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245 | <term><command>ip6tables</command></term>
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246 | <listitem>
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247 | <para>is used to set up, maintain, and inspect the tables of
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248 | IPv6 packet filter rules in the Linux kernel. Several different
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249 | tables may be defined. Each table contains a number of built-in
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250 | chains and may also contain user-defined chains.</para>
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251 | <indexterm zone="iptables ip6tables">
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252 | <primary sortas="b-ip6tables">ip6tables</primary>
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253 | </indexterm>
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254 | </listitem>
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255 | </varlistentry>
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256 |
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257 | <varlistentry id="libip-iptables">
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258 | <term><filename class='libraryfile'>libip*.so</filename></term>
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259 | <listitem>
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260 | <para>library modules are various modules (implemented as dynamic
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261 | libraries) which extend the core functionality of
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262 | <command>iptables</command>.</para>
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263 | <indexterm zone="iptables libip-iptables">
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264 | <primary sortas="c-libip-iptables">libip*.so</primary>
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265 | </indexterm>
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266 | </listitem>
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267 | </varlistentry>
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268 |
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269 | </variablelist>
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270 |
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271 | </sect2>
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272 |
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273 | </sect1>
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