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el_cubano 2008-08-30 01:00:50 +00:00
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8
docs/Actions.xml
View File

@ -113,8 +113,8 @@ ACCEPT - - tcp 135,139,445
<filename>/etc/shorewall/actions</filename> and are defined in
<filename>action.*</filename> files in <filename
class="directory">/etc/shorewall</filename> or in another directory
listed in your CONFIG_PATH (defined in <ulink
url="manpages/shorewall.conf.html">/etc/shorewall/shorewall.conf</ulink>).</para>
listed in your CONFIG_PATH (defined in <filename><ulink
url="manpages/shorewall.conf.html">/etc/shorewall/shorewall.conf</ulink></filename>).</para>
</listitem>
</orderedlist>
</section>
@ -164,8 +164,8 @@ ACCEPT - - tcp 135,139,445
<para>In addition, the default specified in
<filename>/etc/shorewall/shorewall.conf</filename> may be overridden by
specifying a different default in the POLICY column of <ulink
url="manpages/shorewall-policy.html">/etc/shorewall/policy</ulink>.</para>
specifying a different default in the POLICY column of <filename><ulink
url="manpages/shorewall-policy.html">/etc/shorewall/policy</ulink></filename>.</para>
<warning>
<para>Entries in the DROP and REJECT default actions <emphasis

24
docs/Anatomy.xml
View File

@ -64,11 +64,11 @@
<listitem>
<para><emphasis role="bold">Shorewall-lite</emphasis>. Shorewall
allows for central administration of multiple firewalls through use of
Shorewall lite. The full Shorewall product (along with Shorewall-shell
and/or Shorewall-perl) are installed on a central administrative
system where compiled Shorewall scripts are generated. These scripts
are copied to the firewall systems where they run under the control of
Shorewall-lite.</para>
Shorewall lite. The full Shorewall product (including Shorewall-common
with Shorewall-shell and/or Shorewall-perl) is installed on a central
administrative system where compiled Shorewall scripts are generated.
These scripts are copied to the firewall systems where they run under
the control of Shorewall-lite.</para>
</listitem>
</orderedlist>
</section>
@ -77,7 +77,7 @@
<title>Shorewall-common</title>
<para>The Shorewall-common package includes a large number of files which
are installed in /<filename class="directory">sbin</filename>, <filename
are installed in <filename class="directory">/sbin</filename>, <filename
class="directory">/usr/share/shorewall</filename>, <filename
class="directory">/etc/shorewall</filename>,
<filename>/etc/init.d</filename> and <filename
@ -87,7 +87,7 @@
<section id="sbin">
<title>/sbin</title>
<para>The <filename>/sbin/shorewall</filename> shell program is use to
<para>The <filename>/sbin/shorewall</filename> shell program is used to
interact with Shorewall. See <ulink
url="manpages/shorewall.html">shorewall</ulink>(8).</para>
</section>
@ -227,7 +227,7 @@
<para><filename>.modulesdir</filename> - The MODULESDIR setting
(<ulink
url="manpages/shorewall.conf.html">shorewall.conf</ulink>(5)) at the
last <command>start</command> or <command>restart.</command></para>
last <command>start</command> or <command>restart</command>.</para>
</listitem>
<listitem>
@ -358,10 +358,10 @@
<section id="Shorewall-lite">
<title>Shorewall-lite</title>
<para>The Shorewall-lite product includes files installed in /<filename
class="directory">sbin</filename>, <filename
class="directory">/usr/share/shorewall-lite</filename>, /etc/<filename
class="directory">shorewall-lite</filename>,
<para>The Shorewall-lite product includes files installed in <filename
class="directory">/sbin</filename>, <filename
class="directory">/usr/share/shorewall-lite</filename>, <filename
class="directory">/etc/shorewall-lite</filename>,
<filename>/etc/init.d</filename> and <filename
class="directory">/var/lib/shorewall/</filename>. These are described in
the sub-sections that follow.</para>

89
docs/CompiledPrograms.xml
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@ -71,7 +71,7 @@
<listitem>
<para>All extension scripts used are copied into the program (with
the exception of <ulink url="shorewall_extension_scripts.htm">those
executed a compile-time by Shorewall-perl</ulink>). The
executed at compile-time by Shorewall-perl</ulink>). The
ramifications of this are:</para>
<itemizedlist>
@ -152,8 +152,8 @@
<listitem>
<para>Specifies the compiler to use. Overrides the
SHOREWALL_COMPILER setting in <ulink
url="manpages/shorewall.conf.html">shorewall.conf</ulink>.</para>
SHOREWALL_COMPILER setting in <filename><ulink
url="manpages/shorewall.conf.html">shorewall.conf</ulink></filename>.</para>
</listitem>
</varlistentry>
@ -206,15 +206,15 @@
<filename>/etc/shorewall/shorewall.conf</filename> must be readable
by all users on the administrative system. Not all packages secure
the files that way and you may have to change the file permissions
yourself. /sbin/shorewall uses the SHOREWALL_COMPILER setting to
determine which compiler to launch. If the compiler is
shorewall-shell, then the SHOREWALL_SHELL setting from
<filename>/etc/shorewall/shorewall.conf</filename> determines the
shell to use. /sbin/shorewall also uses the VERBOSITY setting for
determining how much output the compiler generates. All other
settings are taken from the <filename>shorewall.conf </filename>file
in the remote systems <firstterm>export directory</firstterm> (see
below).</para>
yourself. <filename>/sbin/shorewall</filename> uses the
SHOREWALL_COMPILER setting to determine which compiler to launch. If
the compiler is shorewall-shell, then the SHOREWALL_SHELL setting
from <filename>/etc/shorewall/shorewall.conf</filename> determines
the shell to use. <filename>/sbin/shorewall</filename> also uses the
VERBOSITY setting for determining how much output the compiler
generates. All other settings are taken from the
<filename>shorewall.conf </filename>file in the remote systems
<firstterm>export directory</firstterm> (see below).</para>
</caution>
</listitem>
@ -234,12 +234,14 @@
<listitem>
<para>On the administrative system you create a separate 'export
directory' for each firewall system. You copy the contents of
/usr/share/shorewall/configfiles into each export directory.</para>
<filename class="directory">/usr/share/shorewall/configfiles</filename>
into each export directory.</para>
</listitem>
<listitem>
<para>If you are running Debian or one of its derivatives like Ubuntu
then edit /etc/default/shorewall-lite and set startup=1.</para>
then edit <filename>/etc/default/shorewall-lite</filename> and set
startup=1.</para>
</listitem>
<listitem>
@ -535,8 +537,8 @@ clean:
<para>Install Shorewall Lite on the firewall system.</para>
<para>If you are running Debian or one of its derivatives like
Ubuntu then edit /etc/default/shorewall-lite and set
startup=1.</para>
Ubuntu then edit <filename>/etc/default/shorewall-lite</filename> and
set startup=1.</para>
</listitem>
<listitem>
@ -546,12 +548,12 @@ clean:
administrative system in the firewall system's
<filename>routestopped</filename> file.</para>
<para>Also, edit the shorewall.conf file in the firewall's export
directory and change the CONFIG_PATH setting to remove <filename
class="directory">/etc/shorewall</filename>. You can replace it with
<filename
class="directory">/usr/share/shorewall/configfiles</filename> if you
like.</para>
<para>Also, edit the <filename>shorewall.conf</filename> file in the
firewall's export directory and change the CONFIG_PATH setting to
remove <filename class="directory">/etc/shorewall</filename>. You can
replace it with <filename
class="directory">/usr/share/shorewall/configfiles</filename> if
you like.</para>
<para>Example:</para>
@ -605,8 +607,9 @@ clean:
url="starting_and_stopping_shorewall.htm#Load"><command>load</command></ulink>
command compiles a firewall script from the configuration files in
the current working directory (using <command>shorewall compile
-e</command>), copies that file to the remote system via scp and
starts Shorewall Lite on the remote system via ssh.</para>
-e</command>), copies that file to the remote system via
<command>scp</command> and starts Shorewall Lite on the remote system
via <command>ssh</command>.</para>
</listitem>
<listitem>
@ -621,14 +624,15 @@ clean:
url="starting_and_stopping_shorewall.htm#Reload"><command>reload</command></ulink>
command compiles a firewall script from the configuration files in
the current working directory (using <command>shorewall compile
-e</command>), copies that file to the remote system via scp and
restarts Shorewall Lite on the remote system via ssh.</para>
-e</command>), copies that file to the remote system via
<command>scp</command> and restarts Shorewall Lite on the remote
system via <command>ssh</command>.</para>
</listitem>
<listitem>
<para>If the kernel/iptables configuration on the firewall later
changes and you need to create a new capabilities file, do the
following:</para>
changes and you need to create a new
<filename>capabilities</filename> file, do the following:</para>
<programlisting><command>/usr/share/shorewall-lite/shorecap &gt; capabilities</command>
<command>scp capabilities &lt;admin system&gt;:&lt;this system's config dir&gt;</command></programlisting>
@ -645,8 +649,9 @@ clean:
<title>The /etc/shorewall/capabilities file and the shorecap
program</title>
<para>As mentioned above, the /etc/shorewall/capabilities file specifies
that kernel/iptables capabilities of the target system. Here is a sample
<para>As mentioned above, the
<filename>/etc/shorewall/capabilities</filename> file specifies that
kernel/iptables capabilities of the target system. Here is a sample
file:</para>
<blockquote>
@ -690,8 +695,8 @@ CAPVERSION=30405</programlisting>
<para>To aid in creating this file, Shorewall Lite includes a
<command>shorecap</command> program. The program is installed in the
<filename>/usr/share/shorewall-lite/</filename> directory and may be run
as follows:</para>
<filename class="directory">/usr/share/shorewall-lite/</filename> directory
and may be run as follows:</para>
<blockquote>
<para><command>[ IPTABLES=&lt;iptables binary&gt; ] [
@ -707,23 +712,23 @@ CAPVERSION=30405</programlisting>
system with Shorewall installed and used when compiling firewall programs
to run on the remote system.</para>
<para>Beginning with Shorewall Lite version 3.2.2, the capabilities file
may also be creating using
<filename>/sbin/shorewall-lite:</filename><blockquote>
<para>Beginning with Shorewall Lite version 3.2.2, the
<filename>capabilities</filename> file may also be creating using
<filename>/sbin/shorewall-lite</filename>:<blockquote>
<para><command>shorewall-lite show -f capabilities &gt;
capabilities</command></para>
</blockquote></para>
<para>Note that unlike the shorecap program, the <command>show
capabilities</command> command shows the kernel's current capabilities; it
does not attempt to load additional kernel modules.</para>
<para>Note that unlike the <command>shorecap</command> program, the
<command>show capabilities</command> command shows the kernel's current
capabilities; it does not attempt to load additional kernel modules.</para>
</section>
<section id="Running">
<title>Running compiled programs directly</title>
<para>Compiled firewall programs are complete programs that support the
following run-line commands:</para>
following command line forms:</para>
<blockquote>
<simplelist>
@ -753,9 +758,9 @@ CAPVERSION=30405</programlisting>
</simplelist>
</blockquote>
<para>The options have their same meaning is when they are passed to
<para>The options have the same meanings as when they are passed to
<filename>/sbin/shorewall</filename> itself. The default VERBOSITY level
is the level specified in the shorewall.conf file used when then program
was compiled.</para>
is the level specified in the <filename>shorewall.conf</filename> file used
when the program was compiled.</para>
</section>
</article>

272
docs/FAQ.xml
View File

@ -58,7 +58,7 @@
<title>(FAQ 37) I just installed Shorewall on Debian and the
/etc/shorewall directory is almost empty!!!</title>
<para><emphasis role="bold">Answer</emphasis>:</para>
<para><emphasis role="bold">Answer:</emphasis></para>
<important>
<para>Once you have installed the .deb package and before you attempt
@ -83,7 +83,7 @@
<title>(FAQ 37a) I just installed Shorewall on Debian and I can't find
the sample configurations.</title>
<para><emphasis role="bold">Answer</emphasis>: With Shorewall 3.x, the
<para><emphasis role="bold">Answer:</emphasis> With Shorewall 3.x, the
samples are included in the shorewall package and are installed in
<filename
class="directory">/usr/share/doc/shorewall/examples/</filename>.
@ -97,7 +97,7 @@
<title>(FAQ 75) I can't find the Shorewall 4.x shorewall-common RPM.
Where is it?</title>
<para><emphasis role="bold">Answer</emphasis>: If you use Simon Matter's
<para><emphasis role="bold">Answer:</emphasis> If you use Simon Matter's
Redhat/Fedora/CentOS rpms, be aware that Simon calls the
<emphasis>shorewall-common</emphasis> RPM
<emphasis>shorewall</emphasis>. So you should download and install the
@ -113,14 +113,14 @@
<title>(FAQ 66) I'm trying to upgrade to Shorewall 4.0; where is the
'shorewall' package?</title>
<para><emphasis role="bold">Answer</emphasis>: Please see the <ulink
<para><emphasis role="bold">Answer:</emphasis> Please see the <ulink
url="upgrade_issues.htm">upgrade issues.</ulink></para>
<section id="faq66a">
<title>(FAQ 66a) I'm trying to upgrade to Shorewall 4.0; do I have to
uninstall the 'shorewall' package?</title>
<para><emphasis role="bold">Answer</emphasis>: Please see the <ulink
<para><emphasis role="bold">Answer:</emphasis> Please see the <ulink
url="upgrade_issues.htm">upgrade issues.</ulink></para>
</section>
@ -128,7 +128,7 @@
<title>(FAQ 66b) I'm trying to upgrade to Shorewall 4.0: which of
these packages do I need to install?</title>
<para><emphasis role="bold">Answer</emphasis>: Please see the <ulink
<para><emphasis role="bold">Answer:</emphasis> Please see the <ulink
url="upgrade_issues.htm">upgrade issues.</ulink></para>
</section>
</section>
@ -142,9 +142,9 @@
allow the installer to replace their working
<filename>/etc/shorewall/shorewall.conf</filename> with one that has
default settings. Failure to forward traffic (such as during masqueraded
net access from a local network) usually means that <ulink
url="???">/etc/shorewall/shorewall.conf</ulink> contains the Debian
default setting IP_FORWARDING=Keep; it should be
net access from a local network) usually means that <filename><ulink
url="manpages/shorewall.conf.html">/etc/shorewall/shorewall.conf</ulink></filename>
contains the Debian default setting IP_FORWARDING=Keep; it should be
IP_FORWARDING=On.</para>
<section id="faq76a">
@ -339,7 +339,7 @@ DNAT net:<emphasis>address</emphasis> loc:<emphasis>local-IP-address</empha
my firewall and have the firewall forward the connection to port 22 on
local system 192.168.1.3. How do I do that?</title>
<para><emphasis role="bold">Answer</emphasis>:In
<para><emphasis role="bold">Answer:</emphasis>In
/<filename>etc/shorewall/rules</filename>:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST PORT
@ -352,7 +352,7 @@ DNAT net loc:192.168.1.3:22 tcp 1022</programlisting>
works fine but when my local users try to connect to the server using
the Firewall's external IP address, it doesn't work.</title>
<para><emphasis role="bold">Answer</emphasis>: See <link
<para><emphasis role="bold">Answer:</emphasis> See <link
linkend="faq2b">FAQ 2b</link>.</para>
</section>
@ -378,13 +378,13 @@ DNAT net fw:192.168.1.1:22 tcp 4104</programlisting>
<title>(FAQ 1f) Why must the server that I port forward to have it's
default gateway set to my Shorewall system's IP address?</title>
<para><emphasis role="bold">Answer</emphasis>: Let's take an example.
<para><emphasis role="bold">Answer:</emphasis> Let's take an example.
Suppose that</para>
<itemizedlist>
<listitem>
<para>Your Shorewall firewall's external IP address is
206.124.146.176 (eth0) and internal IP address 192.168.1.1
206.124.146.176 (eth0) and its internal IP address is 192.168.1.1
(eth1).</para>
</listitem>
@ -419,7 +419,7 @@ DNAT net loc:192.168.1.4 tcp 21 - 206.1
<orderedlist>
<listitem>
<para>16.105.221.4 sends a TCP syn packet to 206.124.146.176
<para>16.105.221.4 sends a TCP SYN packet to 206.124.146.176
specifying destination port 21.</para>
</listitem>
@ -465,7 +465,7 @@ eth1:192.168.1.4 0.0.0.0/0 192.168.1.1 tcp 21</
address (206.124.146.176) to port 993 on Internet host
66.249.93.111</title>
<para><emphasis role="bold">Answer</emphasis>: This requires a vile
<para><emphasis role="bold">Answer:</emphasis> This requires a vile
hack similar to the one in <link linkend="faq2">FAQ 2</link>. Assuming
that your Internet zone is named <emphasis>net</emphasis> and connects
on interface <filename class="devicefile">eth0</filename>:</para>
@ -492,7 +492,7 @@ eth0:66.249.93.111 0.0.0.0/0 206.124.146.176 tcp 993</programlistin
<title>(FAQ 30) I'm confused about when to use DNAT rules and when to
use ACCEPT rules.</title>
<para><emphasis role="bold">Answer</emphasis>:It would be a good idea to
<para><emphasis role="bold">Answer:</emphasis> It would be a good idea to
review the <ulink url="shorewall_quickstart_guide.htm">QuickStart
Guide</ulink> appropriate for your setup; the guides cover this topic in
a tutorial fashion. DNAT rules should be used for connections that need
@ -509,7 +509,7 @@ eth0:66.249.93.111 0.0.0.0/0 206.124.146.176 tcp 993</programlistin
<section id="faq38">
<title>(FAQ 38) Where can I find more information about DNAT?</title>
<para><emphasis role="bold">Answer</emphasis>: Ian Allen has written a
<para><emphasis role="bold">Answer:</emphasis> Ian Allen has written a
<ulink url="http://ian.idallen.ca/dnat.txt">Paper about DNAT and
Linux</ulink>.</para>
</section>
@ -518,7 +518,7 @@ eth0:66.249.93.111 0.0.0.0/0 206.124.146.176 tcp 993</programlistin
<title>(FAQ 48) How do I Set up Transparent HTTP Proxy with
Shorewall?</title>
<para><emphasis role="bold">Answer</emphasis>: See <ulink
<para><emphasis role="bold">Answer:</emphasis> See <ulink
url="Shorewall_Squid_Usage.html">Shorewall_Squid_Usage.html</ulink>.</para>
</section>
</section>
@ -624,8 +624,10 @@ DNAT loc loc:192.168.1.5 tcp www - <emph
DHCP/PPPoE/PPTP/… client to automatically restart Shorewall each
time that you get a new IP address.<note>
<para>If you are running Shorewall 3.2.6 on a Debian-based
system, the call to find_first_interface_address in
/etc/shorewall/params must be preceded with a load of the
system, the call to
<command>find_first_interface_address</command> in
<filename>/etc/shorewall/params</filename> must be preceded with
a load of the
Shorewall function library:<programlisting><command>. /usr/share/shorewall/functions</command>
<command>ETH0_IP=`find_first_interface_address eth0`</command></programlisting></para>
</note></para>
@ -704,7 +706,7 @@ dmz eth2 192.168.2.255 <emphasis role="bold">routeback</emphasis>
www.mydomain.com. That works fine but when my local users try to
connect to www.mydomain.com, it doesn't work.</title>
<para><emphasis role="bold">Answer</emphasis>: Let's assume the
<para><emphasis role="bold">Answer:</emphasis> Let's assume the
following:</para>
<itemizedlist>
@ -728,9 +730,9 @@ dmz eth2 192.168.2.255 <emphasis role="bold">routeback</emphasis>
<para>If your external IP address is dynamic, then you must do the
following:</para>
<para>In <filename>/etc/shorewall/params (or in your
<filename>export-directory/init</filename> file if you are using
Shorewall Lite on the firewall system)</filename>:</para>
<para>In <filename>/etc/shorewall/params</filename> (or in your
<filename>&lt;export directory&gt;/init</filename> file if you are using
Shorewall Lite on the firewall system):</para>
<programlisting><command>ETH0_IP=`find_first_interface_address eth0`</command> </programlisting>
@ -751,7 +753,8 @@ DNAT loc dmz:192.168.2.4 tcp 80 - <emph
<note>
<para>If you are running Shorewall 3.2.6 on a Debian-based system,
the call to find_first_interface_address in /etc/shorewall/params
the call to <command>find_first_interface_address</command> in
<filename>/etc/shorewall/params</filename>
must be preceded with a load of the Shorewall function
library:<programlisting><command>. /usr/share/shorewall/functions</command>
<command>ETH0_IP=`find_first_interface_address eth0`</command></programlisting></para>
@ -762,7 +765,7 @@ DNAT loc dmz:192.168.2.4 tcp 80 - <emph
<title>(FAQ 2c) I tried to apply the answer to FAQ 2 to my external
interface and the net zone and it didn't work. Why?</title>
<para><emphasis role="bold">Answer</emphasis>: Did you set <emphasis
<para><emphasis role="bold">Answer:</emphasis> Did you set <emphasis
role="bold">IP_FORWARDING=On</emphasis> in
<filename>shorewall.conf</filename>?</para>
</section>
@ -776,13 +779,14 @@ DNAT loc dmz:192.168.2.4 tcp 80 - <emph
<title>(FAQ 63) I just blacklisted IP address 206.124.146.176 and I can
still ping it. What did I do wrong?</title>
<para><emphasis role="bold">Answer</emphasis>: Nothing.</para>
<para><emphasis role="bold">Answer:</emphasis> Nothing.</para>
<para>Blacklisting an IP address blocks incoming traffic from that IP
address. And if you set BLACKLISTNEWONLY=Yes in shorewall.conf, then
only new connections <emphasis role="bold">from</emphasis> that address
are disallowed; traffic from that address that is part of an established
connection (such as ping replies) is allowed.</para>
address. And if you set BLACKLISTNEWONLY=Yes in
<filename>shorewall.conf</filename>, then only new connections
<emphasis role="bold">from</emphasis> that address are disallowed;
traffic from that address that is part of an established connection
(such as ping replies) is allowed.</para>
</section>
</section>
@ -794,7 +798,7 @@ DNAT loc dmz:192.168.2.4 tcp 80 - <emph
Shorewall. What do I do?</title>
<para><emphasis role="bold">Answer:</emphasis> There is an <ulink
url="http://www.kfki.hu/%7Ekadlec/sw/netfilter/newnat-suite/">H.323
url="http://www.kfki.hu/~kadlec/sw/netfilter/newnat-suite/">H.323
connection tracking/NAT module</ulink> that helps with Netmeeting. Note
however that one of the Netfilter developers recently posted the
following:</para>
@ -965,8 +969,9 @@ to debug/develop the newnat interface.</programlisting></para>
</listitem>
<listitem>
<para>The entry for the local network in the /etc/shorewall/masq
file is wrong or missing.</para>
<para>The entry for the local network in the
<filename>/etc/shorewall/masq</filename> file is wrong or
missing.</para>
</listitem>
<listitem>
@ -993,7 +998,7 @@ to debug/develop the newnat interface.</programlisting></para>
<section id="faq29">
<title>(FAQ 29) FTP Doesn't Work</title>
<para><emphasis role="bold">Answer</emphasis>:See the <ulink
<para><emphasis role="bold">Answer:</emphasis> See the <ulink
url="FTP.html">Shorewall and FTP page</ulink>.</para>
</section>
@ -1002,23 +1007,23 @@ to debug/develop the newnat interface.</programlisting></para>
sites fail. Connections to the same sites from the firewall itself work
fine. What's wrong.</title>
<para><emphasis role="bold">Answer</emphasis>: Most likely, you need to
set CLAMPMSS=Yes in <ulink
url="manpages/shorewall.conf.html">/etc/shorewall/shorewall.conf</ulink>.</para>
<para><emphasis role="bold">Answer:</emphasis> Most likely, you need to
set CLAMPMSS=Yes in <filename><ulink
url="manpages/shorewall.conf.html">/etc/shorewall/shorewall.conf</ulink></filename>.</para>
</section>
<section id="faq35">
<title>(FAQ 35) I have two Ethernet interfaces to my local network which
I have bridged. When Shorewall is started, I'm unable to pass traffic
through the bridge. I have defined the bridge interface (br0) as the
local interface in /etc/shorewall/interfaces; the bridged Ethernet
interfaces are not defined to Shorewall. How do I tell Shorewall to
allow traffic through the bridge?</title>
local interface in <filename>/etc/shorewall/interfaces</filename>; the
bridged Ethernet interfaces are not defined to Shorewall. How do I tell
Shorewall to allow traffic through the bridge?</title>
<para><emphasis role="bold">Answer</emphasis>: Add the
<para><emphasis role="bold">Answer:</emphasis> Add the
<firstterm>routeback</firstterm> option to <filename
class="devicefile">br0</filename> in <ulink
url="manpages/shorewall-interfaces.html">/etc/shorewall/interfaces</ulink>.</para>
class="devicefile">br0</filename> in <filename><ulink
url="manpages/shorewall-interfaces.html">/etc/shorewall/interfaces</ulink></filename>.</para>
<para>For more information on this type of configuration, see the <ulink
url="SimpleBridge.html">Shorewall Simple Bridge
@ -1063,14 +1068,14 @@ to debug/develop the newnat interface.</programlisting></para>
kernel's equivalent of syslog (see <quote>man syslog</quote>) to log
messages. It always uses the LOG_KERN (kern) facility (see <quote>man
openlog</quote>) and you get to choose the log level (again, see
<quote>man syslog</quote>) in your <ulink
url="manpages/shorewall-policy.html">policies</ulink> and <ulink
url="manpages/shorewall-rules.html">rules</ulink>. The destination for
messages logged by syslog is controlled by
<quote>man syslog</quote>) in your <filename><ulink
url="manpages/shorewall-policy.html">policies</ulink></filename> and
<filename><ulink url="manpages/shorewall-rules.html">rules</ulink></filename>.
The destination for messages logged by syslog is controlled by
<filename>/etc/syslog.conf</filename> (see <quote>man
syslog.conf</quote>). When you have changed /etc/syslog.conf, be sure to
restart syslogd (on a RedHat system, <quote>service syslog
restart</quote>).</para>
syslog.conf</quote>). When you have changed
<filename>/etc/syslog.conf</filename>, be sure to restart syslogd (on a
RedHat system, <quote>service syslog restart</quote>).</para>
<para>By default, older versions of Shorewall rate-limited log messages
through <ulink url="manpages/shorewall.conf.html">settings</ulink> in
@ -1092,11 +1097,9 @@ LOGBURST=""</programlisting>
<literallayout>
<ulink url="http://www.shorewall.net/pub/shorewall/parsefw/">http://www.shorewall.net/pub/shorewall/parsefw/</ulink>
<ulink url="http://www.fireparse.com">http://www.fireparse.com</ulink>
<ulink url="http://aaron.marasco.com/linux.html">http://aaron.marasco.com/linux.html</ulink>
<ulink url="http://cert.uni-stuttgart.de/projects/fwlogwatch">http://cert.uni-stuttgart.de/projects/fwlogwatch</ulink>
<ulink url="http://www.logwatch.org">http://www.logwatch.org</ulink>
<ulink url="http://gege.org/iptables">http://gege.org/iptables</ulink>
<ulink url="http://home.regit.org/ulogd-php.html">http://home.regit.org/ulogd-php.html</ulink>
</literallayout>
<para>I personally use <ulink
@ -1131,10 +1134,10 @@ LOGBURST=""</programlisting>
<section id="faq6b">
<title>(FAQ 6b) DROP messages on port 10619 are flooding the logs with
their connect requests. Can i exclude these error messages for this
their connect requests. Can I exclude these error messages for this
port temporarily from logging in Shorewall?</title>
<para><emphasis role="bold">Answer</emphasis>:Temporarily add the
<para><emphasis role="bold">Answer:</emphasis> Temporarily add the
following rule:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
@ -1153,7 +1156,7 @@ DROP net fw udp 10619</programlisting>
<title>(FAQ 6d) Why is the MAC address in Shorewall log messages so
long? I thought MAC addresses were only 6 bytes in length.</title>
<para><emphasis role="bold">Answer</emphasis>:What is labeled as the
<para><emphasis role="bold">Answer:</emphasis> What is labeled as the
MAC address in a Netfilter (Shorewall) log message is actually the
Ethernet frame header. It contains:</para>
@ -1228,7 +1231,8 @@ teastep@ursa:~$ </programlisting>The first number determines the maximum log
<para>If, on your system, the first number is 7 or greater, then the
default Shorewall configurations will cause messages to be written to
your console. The simplest solution is to add this to your
/etc/sysctl.conf file:<programlisting>kernel.printk = 4 4 1 7</programlisting></para>
<filename>/etc/sysctl.conf</filename>
file:<programlisting>kernel.printk = 4 4 1 7</programlisting></para>
<para>then<programlisting><command>sysctl -p /etc/sysctl.conf</command></programlisting></para>
@ -1319,10 +1323,10 @@ teastep@ursa:~$ </programlisting>The first number determines the maximum log
or all2all</term>
<listitem>
<para>You have a <ulink
url="manpages/shorewall-policy.html">policy</ulink> that specifies
a log level and this packet is being logged under that policy. If
you intend to ACCEPT this traffic then you need a <ulink
<para>You have a <filename><ulink
url="manpages/shorewall-policy.html">policy</ulink></filename> that
specifies a log level and this packet is being logged under that
policy. If you intend to ACCEPT this traffic then you need a <ulink
url="manpages/shorewall-rules.html">rule</ulink> to that
effect.</para>
@ -1399,7 +1403,7 @@ teastep@ursa:~$ </programlisting>The first number determines the maximum log
role="bold">routeback</emphasis> option on that interface in
<filename> <ulink
url="manpages/shorewall-interfaces.html">/etc/shorewall/interfaces</ulink>
, </filename>you need the <emphasis
</filename>, you need the <emphasis
role="bold">routeback</emphasis> option in the relevant entry in
<filename> <ulink
url="manpages/shorewall-hosts.html">/etc/shorewall/hosts</ulink>
@ -1528,9 +1532,6 @@ teastep@ursa:~$ </programlisting>The first number determines the maximum log
</varlistentry>
</variablelist>
<para>For additional information about the log message, see <ulink
url="http://logi.cc/linux/netfilter-log-format.php3">http://logi.cc/linux/netfilter-log-format.php3</ulink>.</para>
<para>In this case, 192.168.2.2 was in the <quote>dmz</quote> zone and
192.168.1.3 is in the <quote>loc</quote> zone. I was missing the
rule:</para>
@ -1564,7 +1565,7 @@ teastep@ursa:~$ </programlisting>The first number determines the maximum log
(ICMP) with <quote>ping</quote>, ICMP is a key piece of IP. ICMP is used
to report problems back to the sender of a packet; this is what is
happening here. Unfortunately, where NAT is involved (including SNAT,
DNAT and Masquerade), there are a lot of broken implementations. That is
DNAT and Masquerade), there are many broken implementations. That is
what you are seeing with these messages. When Netfilter displays these
messages, the part before the "[" describes the ICMP packet and the part
between the "[" and "]" describes the packet for which the ICMP is a
@ -1607,7 +1608,7 @@ teastep@ursa:~$ </programlisting>The first number determines the maximum log
SRC=130.252.100.59 DST=206.124.146.176 LEN=64 TOS=0x00 PREC=0x00 TTL=43 ID=42444 DF
PROTO=TCP SPT=2215 DPT=139 WINDOW=53760 RES=0x00 SYN URGP=0</programlisting>
<para><emphasis role="bold">Answer</emphasis>: Please refer to the
<para><emphasis role="bold">Answer:</emphasis> Please refer to the
<ulink url="NetfilterOverview.html">Shorewall Netfilter
Documentation</ulink>. Logging of REDIRECT and DNAT rules occurs in the
nat table's PREROUTING chain where the original destination IP address
@ -1637,7 +1638,7 @@ modprobe: Can't locate module iptable_raw</programlisting>
<title>(FAQ 32) My firewall has two connections to the Internet from two
different ISPs. How do I set this up in Shorewall?</title>
<para><emphasis role="bold">Answer</emphasis>: See <ulink
<para><emphasis role="bold">Answer:</emphasis> See <ulink
url="MultiISP.html">this article on Shorewall and Multiple
ISPs</ulink>.</para>
</section>
@ -1646,7 +1647,7 @@ modprobe: Can't locate module iptable_raw</programlisting>
<title>(FAQ 49) When I start Shorewall, my routing table gets blown
away. Why does Shorewall do that?</title>
<para><emphasis role="bold">Answer</emphasis>: This is usually the
<para><emphasis role="bold">Answer:</emphasis> This is usually the
consequence of a one-to-one nat configuration blunder:</para>
<orderedlist>
@ -1679,10 +1680,10 @@ modprobe: Can't locate module iptable_raw</programlisting>
stop</quote>, I can't connect to anything. Why doesn't that command
work?</title>
<para><emphasis role="bold">Answer</emphasis>:The <quote>
<para><emphasis role="bold">Answer:</emphasis> The <quote>
<command>stop</command> </quote> command is intended to place your
firewall into a safe state whereby only those hosts listed in
<filename>/etc/shorewall/routestopped</filename>' are activated. If you
<filename>/etc/shorewall/routestopped</filename> are activated. If you
want to totally open up your firewall, you must use the <quote>
<command>shorewall[-lite] clear</command> </quote> command.</para>
</section>
@ -1723,8 +1724,8 @@ rmmod ipchains</command></programlisting>
<title>(FAQ 9) Why can't Shorewall detect my interfaces properly at
startup?</title>
<para>I just installed Shorewall and when I issue the start command, I
see the following:</para>
<para>I just installed Shorewall and when I issue the
<command>start</command> command, I see the following:</para>
<programlisting>Processing /etc/shorewall/params ...
Processing /etc/shorewall/shorewall.conf ...
@ -1745,38 +1746,38 @@ Creating input Chains...
<para>Why can't Shorewall detect my interfaces properly?</para>
<para><emphasis role="bold">Answer:</emphasis> The above output is
perfectly normal. The Net zone is defined as all hosts that are
connected through eth0 and the local zone is defined as all hosts
connected through <filename class="devicefile">eth1</filename>. You can
set the <emphasis role="bold">routefilter</emphasis> option on an
internal interface if you wish to guard against
'<firstterm>Martians</firstterm>' (a Martian is a packet with a source
IP address that is not routed out of the interface on which the packet
was received). If you do that, it is a good idea to also set the
<emphasis role="bold">logmartians</emphasis> option.</para>
perfectly normal. The Net zone is defined as all hosts that are connected
through <filename class="devicefile">eth0</filename> and the local zone
is defined as all hosts connected through <filename
class="devicefile">eth1</filename>. You can set the <emphasis
role="bold">routefilter</emphasis> option on an internal interface if
you wish to guard against '<firstterm>Martians</firstterm>' (a Martian is
a packet with a source IP address that is not routed out of the interface
on which the packet was received). If you do that, it is a good idea to
also set the <emphasis role="bold">logmartians</emphasis> option.</para>
</section>
<section id="faq22">
<title>(FAQ 22) I have some iptables commands that I want to run when
Shorewall starts. Which file do I put them in?</title>
<para><emphasis role="bold">Answer</emphasis>:You can place these
<para><emphasis role="bold">Answer:</emphasis>You can place these
commands in one of the <ulink
url="shorewall_extension_scripts.htm">Shorewall Extension
Scripts</ulink>. Be sure that you look at the contents of the chain(s)
that you will be modifying with your commands to be sure that the
commands will do what they are intended. Many iptables commands
published in HOWTOs and other instructional material use the -A command
which adds the rules to the end of the chain. Most chains that Shorewall
constructs end with an unconditional DROP, ACCEPT or REJECT rule and any
rules that you add after that will be ignored. Check <quote>man
iptables</quote> and look at the -I (--insert) command.</para>
that you will be modifying with your commands so that the commands will
do what is intended. Many iptables commands published in HOWTOs and other
instructional material use the -A command which adds the rules to the end
of the chain. Most chains that Shorewall constructs end with an
unconditional DROP, ACCEPT or REJECT rule and any rules that you add
after that will be ignored. Check <quote>man iptables</quote> and look at
the -I (--insert) command.</para>
</section>
<section id="faq34">
<title>(FAQ 34) How can I speed up Shorewall start (restart)?</title>
<para><emphasis role="bold">Answer</emphasis>: Switch to using <ulink
<para><emphasis role="bold">Answer:</emphasis> Switch to using <ulink
url="Shorewall-perl.html">Shorewall-perl</ulink>.</para>
</section>
@ -1784,7 +1785,7 @@ Creating input Chains...
<title>(FAQ 69) When I restart Shorewall, new connections are blocked
for a long time. Is there a way to avoid that?</title>
<para><emphasis role="bold">Answer</emphasis>: Switch to using <ulink
<para><emphasis role="bold">Answer:</emphasis> Switch to using <ulink
url="Shorewall-perl.html">Shorewall-perl</ulink>.</para>
</section>
@ -1792,11 +1793,11 @@ Creating input Chains...
<title>(FAQ 43) I just installed the Shorewall RPM and Shorewall doesn't
start at boot time.</title>
<para><emphasis role="bold">Answer</emphasis>: When you install using
<para><emphasis role="bold">Answer:</emphasis> When you install using
the "rpm -U" command, Shorewall doesn't run your distribution's tool for
configuring Shorewall startup. You will need to run that tool (insserv,
chkconfig, run-level editor, …) to configure Shorewall to start in the
run-levels that you run your firewall system at.</para>
the default run-levels of your firewall system.</para>
</section>
<section id="faq45">
@ -1816,7 +1817,7 @@ Masqueraded Networks and Hosts:
iptables: Invalid argument
ERROR: Command "/sbin/iptables -t nat -A …" Failed</programlisting>
<para><emphasis role="bold">Answer</emphasis>: 99.999% of the time, this
<para><emphasis role="bold">Answer:</emphasis> 99.999% of the time, this
error is caused by a mismatch between your iptables and kernel.</para>
<orderedlist numeration="loweralpha">
@ -1839,7 +1840,7 @@ iptables: Invalid argument
<title>(FAQ 59) After I start Shorewall, there are lots of unused
Netfilter modules loaded. How do I avoid that?</title>
<para><emphasis role="bold">Answer</emphasis>: Copy
<para><emphasis role="bold">Answer:</emphasis> Copy
<filename>/usr/share/shorewall[-lite]/modules</filename> to
<filename>/etc/shorewall/modules </filename>and modify the copy to
include only the modules that you need.</para>
@ -1893,7 +1894,7 @@ iptables: Invalid argument
<para>ERROR: Command "/sbin/iptables -A FORWARD -m state --state
ESTABLISHED,RELATED -j ACCEPT" failed.</para>
<para><emphasis role="bold">Answer</emphasis>: At a root shell prompt,
<para><emphasis role="bold">Answer:</emphasis> At a root shell prompt,
type the iptables command shown in the error message. If the command
fails, you OpenVZ Netfilter/iptables configuration is incorrect. Until
that command can run without error, no stateful iptables firewall will
@ -1939,11 +1940,11 @@ iptables: Invalid argument
</section>
<section id="faq74">
<title>(FAQ 74) When I "shorewall start" or "shorewall check" on my SuSE
10.0 system, I get FATAL ERROR messages and/or the system
crashes"</title>
<title>(FAQ 74) When I "<command>shorewall start</command>" or
"<command>shorewall check</command>" on my SuSE 10.0 system, I get FATAL
ERROR messages and/or the system crashes"</title>
<para><emphasis role="bold">Answer</emphasis>: These failures result
<para><emphasis role="bold">Answer:</emphasis> These failures result
from trying to load a particular combination of kernel modules. To work
around the problem:</para>
@ -1984,7 +1985,7 @@ iptables: Invalid argument
<title>(FAQ 58) But if I specify 'balance' then won't Shorewall balance
the traffic between the interfaces? I don't want that!</title>
<para><emphasis role="bold">Answer</emphasis>: Suppose that you want all
<para><emphasis role="bold">Answer:</emphasis> Suppose that you want all
traffic to go out through ISP1 (mark 1) unless you specify otherwise.
Then simply add these two rules as the first marking rules in your
<filename>/etc/shorewall/tcrules</filename> file:</para>
@ -2012,7 +2013,7 @@ We have an error talking to the kernel
ERROR: Command "tc filter add dev eth2 parent ffff: protocol ip prio
50 u32 match ip src 0.0.0.0/0 police rate 500kbit burst 10k drop flowid
:1" Failed</programlisting><emphasis
role="bold">Answer</emphasis>: This message indicates that your kernel
role="bold">Answer:</emphasis> This message indicates that your kernel
doesn't have 'traffic policing' support. If your kernel is modularized,
you may be able to resolve the problem by loading the <emphasis
role="bold">act_police</emphasis> kernel module. Other kernel modules
@ -2034,7 +2035,7 @@ We have an error talking to the kernel
<section id="faq10">
<title>(FAQ 10) What Distributions does Shorewall work with?</title>
<para><emphasis role="bold">Answer</emphasis>: Shorewall works with any
<para><emphasis role="bold">Answer:</emphasis> Shorewall works with any
GNU/Linux distribution that includes the <ulink
url="shorewall_prerequisites.htm">proper prerequisites</ulink>.</para>
</section>
@ -2068,7 +2069,7 @@ We have an error talking to the kernel
<section id="faq23">
<title>(FAQ 23) Why do you use such ugly fonts on your web site?</title>
<para><emphasis role="bold">Answer</emphasis>: The Shorewall web site is
<para><emphasis role="bold">Answer:</emphasis> The Shorewall web site is
almost font neutral (it doesn't explicitly specify fonts except on a few
pages) so the fonts you see are largely the default fonts configured in
your browser. If you don't like them then reconfigure your
@ -2079,7 +2080,7 @@ We have an error talking to the kernel
<title>(FAQ 25) How do I tell which version of Shorewall or Shorewall
Lite I am running?</title>
<para><emphasis role="bold">Answer</emphasis>: At the shell prompt,
<para><emphasis role="bold">Answer:</emphasis> At the shell prompt,
type:</para>
<programlisting><command>/sbin/shorewall[-lite] version</command> </programlisting>
@ -2088,7 +2089,7 @@ We have an error talking to the kernel
<title>(FAQ 25a) How do I tell which version of Shorewall-perl and
Shorewall-shell that I have installed?</title>
<para><emphasis role="bold">Answer</emphasis>: At the shell prompt,
<para><emphasis role="bold">Answer:</emphasis> At the shell prompt,
type:</para>
<programlisting><command>/sbin/shorewall version -a</command> </programlisting>
@ -2104,7 +2105,7 @@ We have an error talking to the kernel
internal LAP IP address as the source address?</term>
<listitem>
<para><emphasis role="bold">Answer</emphasis>: Yes.</para>
<para><emphasis role="bold">Answer:</emphasis> Yes.</para>
</listitem>
</varlistentry>
@ -2113,7 +2114,7 @@ We have an error talking to the kernel
fragments?</term>
<listitem>
<para><emphasis role="bold">Answer</emphasis>: This is the
<para><emphasis role="bold">Answer:</emphasis> This is the
responsibility of the IP stack, not the Netfilter-based firewall
since fragment reassembly occurs before the stateful packet filter
ever touches each packet.</para>
@ -2125,7 +2126,7 @@ We have an error talking to the kernel
broadcast address as the source address?</term>
<listitem>
<para><emphasis role="bold">Answer</emphasis>: Shorewall can be
<para><emphasis role="bold">Answer:</emphasis> Shorewall can be
configured to do that using the <ulink
url="blacklisting_support.htm">blacklisting</ulink> facility.
Shorewall versions 2.0.0 and later filter these packets under the
@ -2139,7 +2140,7 @@ We have an error talking to the kernel
source and destination address?</term>
<listitem>
<para><emphasis role="bold">Answer</emphasis>: Yes, if the <ulink
<para><emphasis role="bold">Answer:</emphasis> Yes, if the <ulink
url="manpages/shorewall-interfaces.html">routefilter interface
option</ulink> is selected.</para>
</listitem>
@ -2149,7 +2150,7 @@ We have an error talking to the kernel
<term>DOS: - SYN Dos - ICMP Dos - Per-host Dos protection</term>
<listitem>
<para><emphasis role="bold">Answer</emphasis>: Shorewall has
<para><emphasis role="bold">Answer:</emphasis> Shorewall has
facilities for limiting SYN and ICMP packets. Netfilter as
included in standard Linux kernels doesn't support per-remote-host
limiting except by explicit rule that specifies the host IP
@ -2162,7 +2163,7 @@ We have an error talking to the kernel
<section id="faq65">
<title>(FAQ 65) How do I accomplish failover with Shorewall?</title>
<para><emphasis role="bold">Answer</emphasis>: <ulink
<para><emphasis role="bold">Answer:</emphasis> <ulink
url="http://linuxman.wikispaces.com/Clustering+Shorewall">This article
by Paul Gear</ulink> should help you get started.</para>
</section>
@ -2182,8 +2183,8 @@ We have an error talking to the kernel
modem in/out but still block all other rfc1918 addresses?</para>
<para><emphasis role="bold">Answer:</emphasis> Add the following to
<ulink
url="manpages/shorewall-rfc1918.html">/etc/shorewall/rfc1918</ulink>
<filename><ulink
url="manpages/shorewall-rfc1918.html">/etc/shorewall/rfc1918</ulink></filename>
(Note: If you are running Shorewall 2.0.0 or later, you may need to
first copy <filename>/usr/share/shorewall/rfc1918</filename> to
<filename>/etc/shorewall/rfc1918</filename>):</para>
@ -2197,9 +2198,10 @@ We have an error talking to the kernel
<note>
<para>If you add a second IP address to your external firewall
interface to correspond to the modem address, you must also make an
entry in /etc/shorewall/rfc1918 for that address. For example, if you
configure the address 192.168.100.2 on your firewall, then you would
add two entries to /etc/shorewall/rfc1918:</para>
entry in <filename>/etc/shorewall/rfc1918</filename> for that address.
For example, if you configure the address 192.168.100.2 on your
firewall, then you would add two entries to
<filename>/etc/shorewall/rfc1918</filename>:</para>
<programlisting>#SUBNET TARGET
192.168.100.1 RETURN
@ -2211,7 +2213,7 @@ We have an error talking to the kernel
DHCP server has an RFC 1918 address. If I enable RFC 1918 filtering on
my external interface, my DHCP client cannot renew its lease.</title>
<para><emphasis role="bold">Answer</emphasis>: The solution is the
<para><emphasis role="bold">Answer:</emphasis> The solution is the
same as <xref linkend="faq14" /> above. Simply substitute the IP
address of your ISPs DHCP server.</para>
</section>
@ -2226,7 +2228,7 @@ We have an error talking to the kernel
<programlisting>Mar 1 18:20:07 Mail kernel: Shorewall:OUTPUT:REJECT:IN= OUT=eth0 SRC=192.168.1.2 DST=192.168.1.1 LEN=60
TOS=0x00 PREC=0x00 TTL=64 ID=26774 DF PROTO=TCP SPT=32797 DPT=80 WINDOW=5840 RES=0x00 SYN URGP=0 </programlisting>
<para><emphasis role="bold">Answer</emphasis>: The fact that the
<para><emphasis role="bold">Answer:</emphasis> The fact that the
message is being logged from the OUTPUT chain means that the
destination IP address is not in any defined zone (see <link
linkend="faq17">FAQ 17</link>). You need to:</para>
@ -2299,7 +2301,7 @@ eth0 eth1 # eth1 = interface to local netwo
<section id="faq53">
<title>(FAQ 53) What is Shorewall Lite?</title>
<para><emphasis role="bold">Answer</emphasis>: Shorewall Lite is a
<para><emphasis role="bold">Answer:</emphasis> Shorewall Lite is a
companion product to Shorewall and is designed to allow you to maintain
all Shorewall configuration information on a single system within your
network. See the <ulink url="CompiledPrograms.html#Lite">Compiled
@ -2310,7 +2312,7 @@ eth0 eth1 # eth1 = interface to local netwo
<title>(FAQ 54) If I want to use Shorewall Lite, do I also need to
install Shorewall on the same system?</title>
<para><emphasis role="bold">Answer</emphasis>: No. In fact, we recommend
<para><emphasis role="bold">Answer:</emphasis> No. In fact, we recommend
that you do <emphasis role="bold">NOT</emphasis> install Shorewall on
systems where you wish to use Shorewall Lite. You must have Shorewall
installed on at least one system within your network in order to use
@ -2321,7 +2323,7 @@ eth0 eth1 # eth1 = interface to local netwo
<title>(FAQ 55) How do I decide which product to use - Shorewall or
Shorewall Lite?</title>
<para><emphasis role="bold">Answer</emphasis>: If you plan to have only
<para><emphasis role="bold">Answer:</emphasis> If you plan to have only
a single firewall system, then Shorewall is the logical choice. I also
think that Shorewall is the appropriate choice for laptop systems that
may need to have their firewall configuration changed while on the road.
@ -2336,7 +2338,7 @@ eth0 eth1 # eth1 = interface to local netwo
<title>(FAQ 60) What are the compatibility restrictions between
Shorewall and Shorewall Lite</title>
<para><emphasis role="bold">Answer</emphasis>: Beginning with version
<para><emphasis role="bold">Answer:</emphasis> Beginning with version
3.2.3, there are no compatibility constraints between Shorewall and
Shorewall-lite.</para>
</section>
@ -2348,7 +2350,7 @@ eth0 eth1 # eth1 = interface to local netwo
<section id="faq70">
<title>(FAQ 70) What is Shorewall-Perl?</title>
<para><emphasis role="bold">Answer</emphasis>: Shorewall-perl is a
<para><emphasis role="bold">Answer:</emphasis> Shorewall-perl is a
re-implementation of the Shorewall configuration compiler written in
Perl.</para>
</section>
@ -2356,7 +2358,7 @@ eth0 eth1 # eth1 = interface to local netwo
<section id="faq71">
<title>(FAQ 71) What are the advantages of using Shorewall-perl?</title>
<para><emphasis role="bold">Answer</emphasis>:</para>
<para><emphasis role="bold">Answer:</emphasis></para>
<itemizedlist>
<listitem>
@ -2395,7 +2397,7 @@ eth0 eth1 # eth1 = interface to local netwo
<title>(FAQ 72) Can I switch to using Shorewall-perl without changing my
Shorewall configuration?</title>
<para><emphasis role="bold">Answer</emphasis>: Maybe yes, maybe no. See
<para><emphasis role="bold">Answer:</emphasis> Maybe yes, maybe no. See
the <ulink url="Shorewall-perl.html">Shorewall Perl article</ulink> for
a list of the incompatibilities between Shorewall-shell and
Shorewall-perl.</para>
@ -2434,17 +2436,17 @@ rmmod nf_conntrack_sip</programlisting>Then change the DONT_LOAD specification
<title>(FAQ 20) I have just set up a server. Do I have to change
Shorewall to allow access to my server from the Internet?</title>
<para><emphasis role="bold">Answer</emphasis>: Yes. Consult the <ulink
<para><emphasis role="bold">Answer:</emphasis> Yes. Consult the <ulink
url="shorewall_quickstart_guide.htm">QuickStart guide</ulink> that you
used during your initial setup for information about how to set up rules
for your server.</para>
</section>
<section id="faq24">
<title>(FAQ 24) How can I allow connections to let's say the ssh port
<title>(FAQ 24) How can I allow connections to, let's say, the ssh port
only from specific IP Addresses on the Internet?</title>
<para><emphasis role="bold">Answer</emphasis>: In the SOURCE column of
<para><emphasis role="bold">Answer:</emphasis> In the SOURCE column of
the rule, follow <quote>net</quote> by a colon and a list of the
host/subnet addresses as a comma-separated list.</para>
@ -2462,7 +2464,7 @@ rmmod nf_conntrack_sip</programlisting>Then change the DONT_LOAD specification
behind the firewall, I get <quote>operation not permitted</quote>. How
can I use nmap with Shorewall?"</title>
<para><emphasis role="bold">Answer</emphasis>: Temporarily remove and
<para><emphasis role="bold">Answer:</emphasis> Temporarily remove and
rejNotSyn, dropNotSyn and dropInvalid rules from
<filename>/etc/shorewall/rules</filename> and restart Shorewall.</para>
</section>
@ -2471,7 +2473,7 @@ rmmod nf_conntrack_sip</programlisting>Then change the DONT_LOAD specification
<title>(FAQ 27) I'm compiling a new kernel for my firewall. What should
I look out for?</title>
<para><emphasis role="bold">Answer</emphasis>: First take a look at the
<para><emphasis role="bold">Answer:</emphasis> First take a look at the
<ulink url="kernel.htm">Shorewall kernel configuration page</ulink>. You
probably also want to be sure that you have selected the <quote>
<emphasis role="bold">NAT of local connections (READ HELP)</emphasis>
@ -2510,7 +2512,7 @@ iptables: Invalid argument
<section id="faq28">
<title>(FAQ 28) How do I use Shorewall as a Bridging Firewall?</title>
<para><emphasis role="bold">Answer</emphasis>: Shorewall Bridging
<para><emphasis role="bold">Answer:</emphasis> Shorewall Bridging
Firewall support is available — <ulink
url="bridge-Shorewall-perl.html">check here for details</ulink>.</para>
</section>
@ -2576,7 +2578,7 @@ REJECT fw net:216.239.39.99 all</programlisting>Given that
<title>(FAQ 42) How can I tell which features my kernel and iptables
support?</title>
<para><emphasis role="bold">Answer</emphasis>: Use the
<para><emphasis role="bold">Answer:</emphasis> Use the
<command>shorewall[-lite] show capabilities</command> command at a root
prompt.</para>