forked from extern/shorewall_code
aa36c47640
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@5940 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
433 lines
16 KiB
XML
433 lines
16 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<refentry>
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<refmeta>
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<refentrytitle>shorewall-interfaces</refentrytitle>
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<manvolnum>5</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>interfaces</refname>
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<refpurpose>Shorewall interfaces file</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<cmdsynopsis>
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<command>/etc/shorewall/interfaces</command>
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</cmdsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>The interfaces file serves to define the firewall's network
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interfaces to Shorewall.</para>
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<para>The columns in the file are as follows.</para>
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<variablelist>
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<varlistentry>
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<term><emphasis role="bold">ZONE</emphasis> —
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<emphasis>zone-name</emphasis></term>
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<listitem>
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<para>Zone for this interface. Must match the name of a zone
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declared in /etc/shorewall/zones. You may not list the firewall zone
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in this column.</para>
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<para>If the interface serves multiple zones that will be defined in
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the <ulink url="shorewall-hosts.html">shorewall-hosts</ulink>(5)
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file, you should place "-" in this column.</para>
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<para>If there are multiple interfaces to the same zone, you must
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list them in separate entries.</para>
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<para>Example:</para>
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<blockquote>
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<programlisting>#ZONE INTERFACE BROADCAST
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loc eth1 -
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loc eth2 -</programlisting>
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</blockquote>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">INTERFACE</emphasis> —
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<emphasis>interface</emphasis></term>
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<listitem>
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<para>Name of interface. Each interface may be listed only once in
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this file. You may NOT specify the name of a "virtual" interface
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(e.g., eth0:0) here; see <ulink
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url="http://www.shorewall.net/FAQ.htm#faq18">http://www.shorewall.net/FAQ.htm#faq18</ulink></para>
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<para>You may use wildcards here by specifying a prefix followed by
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the plus sign ("+"). For example, if you want to make an entry that
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applies to all PPP interfaces, use 'ppp+'; that would match ppp1,
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ppp2, …</para>
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<para>There is no need to define the loopback interface (lo) in this
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file.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">BROADCAST</emphasis> (Optional) —
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{<emphasis role="bold">-</emphasis>|<emphasis
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role="bold">detect</emphasis>|<emphasis>address</emphasis>[,<emphasis>address</emphasis>]...}</term>
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<listitem>
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<para>The broadcast address(es) for the network(s) to which the
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interface belongs. For P-T-P interfaces, this column is left
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blank.If the interface has multiple addresses on multiple subnets
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then list the broadcast addresses as a comma-separated list.</para>
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<para>If you use the special value <emphasis
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role="bold">detect</emphasis>, Shorewall will detect the broadcast
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address(es) for you. If you select this option, the interface must
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be up before the firewall is started.</para>
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<para>If you don't want to give a value for this column but you want
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to enter a value in the OPTIONS column, enter <emphasis
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role="bold">-</emphasis> in this column.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">OPTIONS</emphasis> (Optional) —
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[<emphasis>option</emphasis>[<emphasis
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role="bold">,</emphasis><emphasis>option</emphasis>]...]</term>
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<listitem>
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<para>A comma-separated list of options from the following list. The
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order in which you list the options is not significant but the list
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should have no embedded white space.</para>
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<variablelist>
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<varlistentry>
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<term><emphasis role="bold">dhcp</emphasis></term>
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<listitem>
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<para>Specify this option when any of the following are
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true:</para>
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<orderedlist spacing="compact">
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<listitem>
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<para>the interface gets its IP address via DHCP</para>
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</listitem>
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<listitem>
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<para>the interface is used by a DHCP server running on
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the firewall</para>
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</listitem>
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<listitem>
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<para>you have a static IP but are on a LAN segment with
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lots of DHCP clients.</para>
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</listitem>
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<listitem>
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<para>the interface is a bridge with a DHCP server on one
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port and DHCP clients on another port.</para>
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</listitem>
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</orderedlist>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">norfc1918</emphasis></term>
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<listitem>
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<para>This interface should not receive any packets whose
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source is in one of the ranges reserved by RFC 1918 (i.e.,
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private or "non-routable" addresses). If packet mangling or
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connection-tracking match is enabled in your kernel, packets
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whose destination addresses are reserved by RFC 1918 are also
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rejected.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">routefilter</emphasis></term>
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<listitem>
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<para>Turn on kernel route filtering for this interface
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(anti-spoofing measure). This option can also be enabled
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globally in the <ulink
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url="shorewall.conf.html">shorewall.conf</ulink>(5)
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file.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">logmartians</emphasis></term>
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<listitem>
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<para>Turn on kernel martian logging (logging of packets with
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impossible source addresses. It is strongly suggested that if
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you set <emphasis role="bold">routefilter</emphasis> on an
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interface that you also set <emphasis
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role="bold">logmartians</emphasis>. Even if you do not specify
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the <option>routefilter</option> option, it is a good idea to
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specify <option>logmartians</option> because your distribution
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may be enabling route filtering without you knowing it.</para>
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<para>To find out if route filtering is set on a given
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<replaceable>interface</replaceable>, check the contents of
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<filename>/proc/sys/net/ipv4/conf/<replaceable>interface</replaceable>/rp_filter</filename>
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— a non-zero value indicates that route filtering is
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enabled.</para>
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<para>Example:</para>
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<programlisting> teastep@lists:~$ <command>cat /proc/sys/net/ipv4/conf/eth0/rp_filter </command>
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1
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teastep@lists:~$ </programlisting>
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<para>This option may also be enabled globally in the <ulink
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url="shorewall.conf.html">shorewall.conf</ulink>(5)
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file.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">blacklist</emphasis></term>
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<listitem>
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<para>Check packets arriving on this interface against the
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<ulink
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url="shorewall-blacklist.html">shorewall-blacklist</ulink>(5)
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file.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">maclist</emphasis></term>
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<listitem>
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<para>Connection requests from this interface are compared
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against the contents of <ulink
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url="shorewall-maclist.html">shorewall-maclist</ulink>(5). If
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this option is specified, the interface must be an ethernet
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NIC and must be up before Shorewall is started.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">tcpflags</emphasis></term>
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<listitem>
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<para>Packets arriving on this interface are checked for
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certain illegal combinations of TCP flags. Packets found to
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have such a combination of flags are handled according to the
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setting of TCP_FLAGS_DISPOSITION after having been logged
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according to the setting of TCP_FLAGS_LOG_LEVEL.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">proxyarp</emphasis></term>
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<listitem>
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<para>Sets
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/proc/sys/net/ipv4/conf/<emphasis>interface</emphasis>/proxy_arp.
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Do NOT use this option if you are employing Proxy ARP through
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entries in <ulink
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url="shorewall-proxyarp.html">shorewall-proxyarp</ulink>(5).
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This option is intended solely for use with Proxy ARP
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sub-networking as described at: <ulink
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url="http://tldp.org/HOWTO/Proxy-ARP-Subnet/index.html">http://tldp.org/HOWTO/Proxy-ARP-Subnet/index.html</ulink></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">routeback</emphasis></term>
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<listitem>
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<para>If specified, indicates that Shorewall should include
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rules that allow filtering traffic arriving on this interface
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back out that same interface. This option is also required
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when you have used a wildcard in the INTERFACE column if you
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want to allow traffic between the interfaces that match the
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wildcard.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">arp_filter</emphasis></term>
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<listitem>
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<para>If specified, this interface will only respond to ARP
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who-has requests for IP addresses configured on the interface.
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If not specified, the interface can respond to ARP who-has
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requests for IP addresses on any of the firewall's interface.
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The interface must be up when Shorewall is started.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis
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role="bold">arp_ignore</emphasis>[=<emphasis>number</emphasis>]</term>
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<listitem>
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<para>If specified, this interface will respond to arp
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requests based on the value of <emphasis>number</emphasis>
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(defaults to 1).</para>
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<para>1 - reply only if the target IP address is local address
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configured on the incoming interface</para>
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<para>2 - reply only if the target IP address is local address
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configured on the incoming interface and the sender's IP
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address is part from same subnet on this interface</para>
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<para>3 - do not reply for local addresses configured with
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scope host, only resolutions for global and link</para>
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<para>4-7 - reserved</para>
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<para>8 - do not reply for all local addresses</para>
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<warning>
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<para>Do not specify <emphasis
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role="bold">arp_ignore</emphasis> for any interface involved
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in <ulink url="../ProxyARP.htm">Proxy ARP</ulink>.</para>
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</warning>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">nosmurfs</emphasis></term>
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<listitem>
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<para>Filter packets for smurfs (packets with a broadcast
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address as the source).</para>
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<para>Smurfs will be optionally logged based on the setting of
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SMURF_LOG_LEVEL in <ulink
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url="shorewall.conf.html">shorewall.conf</ulink>(5). After
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logging, the packets are dropped.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">detectnets</emphasis></term>
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<listitem>
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<para>Automatically tailors the zone named in the ZONE column
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to include only those hosts routed through the
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interface.</para>
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<warning>
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<para>Do not set the <emphasis
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role="bold">detectnets</emphasis> option on your internet
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interface.</para>
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</warning>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">sourceroute</emphasis></term>
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<listitem>
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<para>If this option is not specified for an interface, then
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source-routed packets will not be accepted from that interface
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(sets
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/proc/sys/net/ipv4/conf/<emphasis>interface</emphasis>/accept_source_route
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to 1). Only set this option if you know what you are doing.
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This might represent a security risk and is not usually
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needed.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><emphasis role="bold">upnp</emphasis></term>
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<listitem>
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<para>Incoming requests from this interface may be remapped
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via UPNP (upnpd). See <ulink
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url="../UPnP.html">http://www.shorewall.net/UPnP.html</ulink>.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Example</title>
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<variablelist>
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<varlistentry>
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<term>Example 1:</term>
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<listitem>
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<para>Suppose you have eth0 connected to a DSL modem and eth1
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connected to your local network and that your local subnet is
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192.168.1.0/24. The interface gets it's IP address via DHCP from
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subnet 206.191.149.192/27. You have a DMZ with subnet 192.168.2.0/24
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using eth2.</para>
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<para>Your entries for this setup would look like:</para>
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<programlisting>#ZONE INTERFACE BROADCAST OPTIONS
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net eth0 206.191.149.223 dhcp
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loc eth1 192.168.1.255
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dmz eth2 192.168.2.255</programlisting>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Example 2:</term>
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<listitem>
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<para>The same configuration without specifying broadcast addresses
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is:</para>
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<programlisting>#ZONE INTERFACE BROADCAST OPTIONS
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net eth0 detect dhcp
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loc eth1 detect
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dmz eth2 detect</programlisting>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Example 3:</term>
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<listitem>
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<para>You have a simple dial-in system with no ethernet
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connections.</para>
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<programlisting>#ZONE INTERFACE BROADCAST OPTIONS
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net ppp0 -</programlisting>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>FILES</title>
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<para>/etc/shorewall/interfaces</para>
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</refsect1>
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<refsect1>
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<title>See ALSO</title>
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|
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<para><ulink
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url="http://www.shorewall.net/Documentation.htm#Interfaces">http://www.shorewall.net/Documentation.htm#Interfaces</ulink></para>
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<para>shorewall(8), shorewall-accounting(5), shorewall-actions(5),
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shorewall-blacklist(5), shorewall-hosts(5), shorewall-ipsec(5),
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shorewall-maclist(5), shorewall-masq(5), shorewall-nat(5),
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shorewall-netmap(5), shorewall-params(5), shorewall-policy(5),
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shorewall-providers(5), shorewall-proxyarp(5), shorewall-route_routes(5),
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shorewall-routestopped(5), shorewall-rules(5), shorewall.conf(5),
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shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
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shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)</para>
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</refsect1>
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</refentry>
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