shorewall_code/manpages/shorewall-nat.xml
2006-11-22 03:51:39 +00:00

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<?xml version="1.0" encoding="UTF-8"?>
<refentry>
<refmeta>
<refentrytitle>shorewall-nat</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>nat</refname>
<refpurpose>Shorewall one-to-one NAT file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>/etc/shorewall/nat</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>This file is used to define one-to-one Network Address Translation
(NAT).</para>
<warning>
<para>If all you want to do is simple port forwarding, do NOT use this
file. See http://www.shorewall.net/FAQ.htm#faq1. Also, in most cases,
Proxy ARP is a better solution that one-to-one NAT.</para>
</warning>
<para>The columns in the file are as follows.</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">EXTERNAL</emphasis></term>
<listitem>
<para>External IP Address - this should NOT be the primary IP
address of the interface named in the next column and must not be a
DNS Name.</para>
<para>If you put COMMENT in this column, the rest of the line will
be attached as a comment to the Netfilter rule(s) generated by the
following entries in the file. The comment will appear delimited by
"/* ... */" in the output of "shorewall show nat"</para>
<para>To stop the comment from being attached to further rules,
simply include COMMENT on a line by itself.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">INTERFACE</emphasis></term>
<listitem>
<para>Interface that has the <emphasis
role="bold">EXTERNAL</emphasis> address. If ADD_IP_ALIASES=Yes in
shorewall.conf(5), Shorewall will automatically add the EXTERNAL
address to this interface. Also if ADD_IP_ALIASES=Yes, you may
follow the interface name with ":" and a digit to indicate that you
want Shorewall to add the alias with this name (e.g., "eth0:0").
That allows you to see the alias with ifconfig. <emphasis
role="bold">That is the only thing that this name is good for -- you
cannot use it anwhere else in your Shorewall
configuration.</emphasis></para>
<para>If you want to override ADD_IP_ALIASES=Yes for a particular
entry, follow the interface name with ":" and no digit (e.g.,
"eth0:").</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">INTERNAL</emphasis></term>
<listitem>
<para>Internal Address (must not be a DNS Name).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ALL INTERFACES</emphasis></term>
<listitem>
<para>If Yes or yes, NAT will be effective from all hosts. If No or
no (or left empty) then NAT will be effective only through the
interface named in the <emphasis role="bold">INTERFACE</emphasis>
column.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">LOCAL</emphasis></term>
<listitem>
<para>If <emphasis role="bold">Yes</emphasis> or <emphasis
role="bold">yes</emphasis>, NAT will be effective from the firewall
system</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>FILES</title>
<para>/etc/shorewall/nat</para>
</refsect1>
<refsect1>
<title>See ALSO</title>
<para><ulink
url="http://shorewall.net/NAT.htm">http://shorewall.net/NAT.htm</ulink></para>
<para>shorewall(8), shorewall-accounting(5), shorewall-actions(5),
shorewall-blacklist(5), shorewall-hosts(5), shorewall-interfaces(5),
shorewall-maclist(5), shorewall-masq(5), shorewall-netmap(5),
shorewall-params(5), shorewall-policy(5), shorewall-providers(5),
shorewall-proxyarp(5), shorewall-route_routes(5),
shorewall-routestopped(5), shorewall-rules(5), shorewall.conf(5),
shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)</para>
</refsect1>
</refentry>