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Shorewall-docs/standalone.xml
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@ -15,12 +15,10 @@
</author> </author>
</authorgroup> </authorgroup>
<pubdate>2003-11-15</pubdate> <pubdate>2004-01-06</pubdate>
<copyright> <copyright>
<year>2002</year> <year>2002-2004</year>
<year>2003</year>
<holder>Thomas M. Eastep</holder> <holder>Thomas M. Eastep</holder>
</copyright> </copyright>
@ -111,9 +109,10 @@
<section> <section>
<title>PPTP/ADSL</title> <title>PPTP/ADSL</title>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> If you <para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
have an ADSL Modem and you use PPTP to communicate with a server in that
modem, you must make the <ulink url="PPTP.htm#PPTP_ADSL">changes <para>If you have an ADSL Modem and you use PPTP to communicate with a
server in that modem, you must make the <ulink url="PPTP.htm#PPTP_ADSL">changes
recommended here</ulink> <emphasis role="underline">in addition to those recommended here</ulink> <emphasis role="underline">in addition to those
described in the steps below</emphasis>. ADSL with PPTP is most commonly described in the steps below</emphasis>. ADSL with PPTP is most commonly
found in Europe, notably in Austria.</para> found in Europe, notably in Austria.</para>
@ -122,11 +121,13 @@
<section> <section>
<title>Shorewall Concepts</title> <title>Shorewall Concepts</title>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> The <para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
configuration files for Shorewall are contained in the directory
/etc/shorewall -- for simple setups, you only need to deal with a few of <para>The configuration files for Shorewall are contained in the directory
these as described in this guide. After you have <ulink url="Install.htm">installed <filename class="directory">/etc/shorewall</filename> -- for simple
Shorewall</ulink>, <emphasis role="bold">download the <ulink setups, you only need to deal with a few of these as described in this
guide. After you have <ulink url="Install.htm">installed Shorewall</ulink>,
<emphasis role="bold">download the <ulink
url="http://www1.shorewall.net/pub/shorewall/Samples/">one-interface url="http://www1.shorewall.net/pub/shorewall/Samples/">one-interface
sample</ulink>, un-tar it (tar -zxvf one-interface.tgz) and and copy the sample</ulink>, un-tar it (tar -zxvf one-interface.tgz) and and copy the
files to /etc/shorewall (they will replace files with the same names that files to /etc/shorewall (they will replace files with the same names that
@ -160,7 +161,7 @@
</tgroup> </tgroup>
</informaltable> </informaltable>
<para>Shorewall zones are defined in <ulink url="Documentation.htm#Zones">/etc/shorewall/zones</ulink>.</para> <para>Shorewall zones are defined in <ulink url="Documentation.htm#Zones"><filename>/etc/shorewall/zones</filename></ulink>.</para>
<para>Shorewall also recognizes the firewall system as its own zone - by <para>Shorewall also recognizes the firewall system as its own zone - by
default, the firewall itself is known as <emphasis role="bold">fw</emphasis>.</para> default, the firewall itself is known as <emphasis role="bold">fw</emphasis>.</para>
@ -171,84 +172,33 @@
<itemizedlist> <itemizedlist>
<listitem> <listitem>
<para>You express your default policy for connections from one zone to <para>You express your default policy for connections from one zone to
another zone in the <ulink url="Documentation.htm#Policy">/etc/shorewall/policy</ulink> another zone in the <ulink url="Documentation.htm#Policy"><filename>/etc/shorewall/policy</filename></ulink>
file.</para> file.</para>
</listitem> </listitem>
<listitem> <listitem>
<para>You define exceptions to those default policies in the <ulink <para>You define exceptions to those default policies in the <ulink
url="Documentation.htm#Rules">/etc/shorewall/rules</ulink> file.</para> url="Documentation.htm#Rules"><filename>/etc/shorewall/rules</filename></ulink>
file.</para>
</listitem> </listitem>
</itemizedlist> </itemizedlist>
<para>For each connection request entering the firewall, the request is <para>For each connection request entering the firewall, the request is
first checked against the /etc/shorewall/rules file. If no rule in that first checked against the <filename><filename>/etc/shorewall/rules</filename></filename>
file matches the connection request then the first policy in file. If no rule in that file matches the connection request then the
/etc/shorewall/policy that matches the request is applied. If that policy first policy in <filename>/etc/shorewall/policy</filename> that matches
is REJECT or DROP the request is first checked against the rules in the request is applied. If that policy is REJECT or DROP the request is
/etc/shorewall/common if that file exists; otherwise the rules in first checked against the rules in /etc/shorewall/common if that file
/etc/shorewall/common.def are checked.</para> exists; otherwise the rules in <filename>/etc/shorewall/common.def</filename>
are checked.</para>
<para>The /etc/shorewall/policy file included with the one-interface <para>The <filename>/etc/shorewall/policy</filename> file included with
sample has the following policies:</para> the one-interface sample has the following policies:</para>
<table> <programlisting>#SOURCE ZONE DESTINATION ZONE POLICY LOG LEVEL LIMIT:BURST
<title>one-interface sample /etc/shorewall/policy</title> fw net ACCEPT
net all DROP info
<tgroup cols="5"> all all REJECT info</programlisting>
<thead>
<row>
<entry align="center">SOURCE ZONE</entry>
<entry align="center">DESTINATION ZONE</entry>
<entry align="center">POLICY</entry>
<entry align="center">LOG LEVEL</entry>
<entry align="center">LIMIT:BURST</entry>
</row>
</thead>
<tbody>
<row>
<entry>fw</entry>
<entry>net</entry>
<entry>ACCEPT</entry>
<entry></entry>
<entry></entry>
</row>
<row>
<entry>net</entry>
<entry>all</entry>
<entry>DROP</entry>
<entry>info</entry>
<entry></entry>
</row>
<row>
<entry>all</entry>
<entry>all</entry>
<entry>REJECT</entry>
<entry>info</entry>
<entry></entry>
</row>
</tbody>
</tgroup>
</table>
<para>The above policy will:</para> <para>The above policy will:</para>
@ -268,8 +218,8 @@
</listitem> </listitem>
</orderedlist> </orderedlist>
<para>At this point, edit your /etc/shorewall/policy and make any changes <para>At this point, edit your <filename>/etc/shorewall/policy</filename>
that you wish.</para> and make any changes that you wish.</para>
</section> </section>
<section> <section>
@ -287,12 +237,14 @@
<emphasis role="bold">ppp0</emphasis>. If you connect using ISDN, your <emphasis role="bold">ppp0</emphasis>. If you connect using ISDN, your
external interface will be <emphasis role="bold">ippp0</emphasis>.</para> external interface will be <emphasis role="bold">ippp0</emphasis>.</para>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> The <para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
Shorewall one-interface sample configuration assumes that the external
interface is <emphasis role="bold">eth0</emphasis>. If your configuration <para>The Shorewall one-interface sample configuration assumes that the
is different, you will have to modify the sample /etc/shorewall/interfaces external interface is <emphasis role="bold">eth0</emphasis>. If your
file accordingly. While you are there, you may wish to review the list of configuration is different, you will have to modify the sample
options that are specified for the interface. Some hints:</para> /etc/shorewall/interfaces file accordingly. While you are there, you may
wish to review the list of options that are specified for the interface.
Some hints:</para>
<tip> <tip>
<para>If your external interface is <emphasis role="bold">ppp0</emphasis> <para>If your external interface is <emphasis role="bold">ppp0</emphasis>
@ -309,9 +261,9 @@
<tip> <tip>
<para>If you specify <emphasis>norfc1918</emphasis> for your external <para>If you specify <emphasis>norfc1918</emphasis> for your external
interface, you will want to check the <ulink url="errata.htm">Shorewall interface, you will want to check the <ulink url="errata.htm">Shorewall
Errata</ulink> periodically for updates to the /etc/shorewall/rfc1918 Errata</ulink> periodically for updates to the <filename>/etc/shorewall/rfc1918
file. Alternatively, you can <ulink url="myfiles.htm#RFC1918">strip down file</filename>. Alternatively, you can <ulink url="myfiles.htm#RFC1918">strip
your /etc/shorewall/rfc1918 files as I do</ulink>.</para> down your <filename>/etc/shorewall/rfc1918</filename> file as I do</ulink>.</para>
</tip> </tip>
</section> </section>
@ -332,70 +284,31 @@
Translation</emphasis> to rewrite packet headers when forwarding to/from Translation</emphasis> to rewrite packet headers when forwarding to/from
the internet.</para> the internet.</para>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> Before <para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
starting Shorewall, you should look at the IP address of your external
interface and if it is one of the above ranges, you should remove the <para>Before starting Shorewall, you should look at the IP address of your
<quote>norfc1918</quote> option from the entry in external interface and if it is one of the above ranges, you should remove
/etc/shorewall/interfaces.</para> the <quote>norfc1918</quote> option from the entry in
<filename>/etc/shorewall/interfaces</filename>.</para>
</section> </section>
<section> <section>
<title>Enabling other Connections</title> <title>Enabling other Connections</title>
<para>If you wish to enable connections from the internet to your <para>If you wish to enable connections from the internet to your
firewall, the general format is:</para> firewall, the general format of a rule in <filename>/etc/shorewall/rules</filename>
is:</para>
<table> <programlisting>#ACTION SOURCE DESTINATION PROTO DEST PORT(S)
<title>/etc/shorewall/rules</title> ACCEPT net fw <emphasis>&#60;protocol&#62;</emphasis> <emphasis>&#60;port&#62;</emphasis></programlisting>
<tgroup cols="7">
<thead>
<row>
<entry align="center">ACTION</entry>
<entry align="center">SOURCE</entry>
<entry align="center">DESTINATION</entry>
<entry align="center">PROTOCOL</entry>
<entry align="center">PORT</entry>
<entry align="center">SOURCE PORT</entry>
<entry align="center">ORIGINAL ADDRESS</entry>
</row>
</thead>
<tbody>
<row>
<entry>ACCEPT</entry>
<entry>net</entry>
<entry>fw</entry>
<entry>&#60;<emphasis>protocol</emphasis>&#62;</entry>
<entry>&#60;<emphasis>port</emphasis>&#62;</entry>
<entry></entry>
<entry></entry>
</row>
</tbody>
</tgroup>
</table>
<example> <example>
<title>You want to run a Web Server and a POP3 Server on your firewall <title>You want to run a Web Server and a POP3 Server on your firewall
system:</title> system:</title>
<para><table><title>/etc/shorewall/rules</title><tgroup cols="7"><thead><row><entry <para><programlisting>#ACTION SOURCE DESTINATION PROTO DEST PORT(S)
align="center">ACTION</entry><entry align="center">SOURCE</entry><entry ACCEPT net fw tcp 80
align="center">DESTINATION</entry><entry align="center">PROTOCOL</entry><entry ACCEPT net fw tcp 110</programlisting></para>
align="center">PORT</entry><entry align="center">SOURCE PORT</entry><entry
align="center">ORIGINAL ADDRESS</entry></row></thead><tbody><row><entry>ACCEPT</entry><entry>net</entry><entry>fw</entry><entry>tcp</entry><entry>80</entry><entry></entry><entry></entry></row><row><entry>ACCEPT</entry><entry>net</entry><entry>fw</entry><entry>tcp</entry><entry>110</entry><entry></entry><entry></entry></row></tbody></tgroup></table></para>
</example> </example>
<para>If you don&#39;t know what port and protocol a particular <para>If you don&#39;t know what port and protocol a particular
@ -406,87 +319,52 @@
it uses clear text (even for login!). If you want shell access to your it uses clear text (even for login!). If you want shell access to your
firewall from the internet, use SSH:</para> firewall from the internet, use SSH:</para>
<table> <programlisting>#ACTION SOURCE DESTINATION PROTO DEST PORT(S)
<title>/etc/shorewall/rules</title> ACCEPT net fw tcp 22</programlisting>
<tgroup cols="7">
<thead>
<row>
<entry align="center">ACTION</entry>
<entry align="center">SOURCE</entry>
<entry align="center">DESTINATION</entry>
<entry align="center">PROTOCOL</entry>
<entry align="center">PORT</entry>
<entry align="center">SOURCE PORT</entry>
<entry align="center">ORIGINAL ADDRESS</entry>
</row>
</thead>
<tbody>
<row>
<entry>ACCEPT</entry>
<entry>net</entry>
<entry>fw</entry>
<entry>tcp</entry>
<entry>22</entry>
<entry></entry>
<entry></entry>
</row>
</tbody>
</tgroup>
</table>
</important> </important>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> At this <para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
point, edit /etc/shorewall/rules to add other connections as desired.</para>
<para>At this point, edit /etc/shorewall/rules to add other connections as
desired.</para>
</section> </section>
<section> <section>
<title>Starting and Stopping Your Firewall</title> <title>Starting and Stopping Your Firewall</title>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> The <para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<ulink url="Install.htm">installation procedure</ulink> configures your
system to start Shorewall at system boot but beginning with Shorewall <para>The <ulink url="Install.htm">installation procedure</ulink>
version 1.3.9 startup is disabled so that your system won&#39;t try to configures your system to start Shorewall at system boot but beginning
start Shorewall before configuration is complete. Once you have completed with Shorewall version 1.3.9 startup is disabled so that your system
configuration of your firewall, you can enable Shorewall startup by won&#39;t try to start Shorewall before configuration is complete. Once
removing the file /etc/shorewall/startup_disabled.</para> you have completed configuration of your firewall, you can enable
Shorewall startup by removing the file <filename>/etc/shorewall/startup_disabled</filename>.</para>
<important> <important>
<para><emphasis role="bold">Users of the .deb package must edit <para><emphasis role="bold">Users of the .deb package must edit
/etc/default/shorewall and set <quote>startup=1</quote>.</emphasis></para> <filename>/etc/default/shorewall</filename> and set <quote>startup=1</quote>.</emphasis></para>
</important> </important>
<para>The firewall is started using the <quote>shorewall start</quote> <para>The firewall is started using the <quote><command>shorewall start</command></quote>
command and stopped using <quote>shorewall stop</quote>. When the firewall command and stopped using <quote><command>shorewall stop</command></quote>.
is stopped, routing is enabled on those hosts that have an entry in <ulink When the firewall is stopped, routing is enabled on those hosts that have
url="Documentation.htm#Routestopped">/etc/shorewall/routestopped</ulink>. an entry in <filename><ulink url="Documentation.htm#Routestopped">/etc/shorewall/routestopped</ulink></filename>.
A running firewall may be restarted using the <quote>shorewall restart</quote> A running firewall may be restarted using the <quote><command>shorewall
command. If you want to totally remove any trace of Shorewall from your restart</command></quote> command. If you want to totally remove any trace
Netfilter configuration, use <quote>shorewall clear</quote>.</para> of Shorewall from your Netfilter configuration, use <quote><command>shorewall
clear</command></quote>.</para>
<warning> <warning>
<para>If you are connected to your firewall from the internet, do not <para>If you are connected to your firewall from the internet, do not
issue a <quote>shorewall stop</quote> command unless you have added an issue a <quote><command>shorewall stop</command></quote> command unless
entry for the IP address that you are connected from to <ulink you have added an entry for the IP address that you are connected from
url="Documentation.htm#Routestopped">/etc/shorewall/routestopped</ulink>. to <ulink url="Documentation.htm#Routestopped"><filename>/etc/shorewall/routestopped</filename></ulink>.
Also, I don&#39;t recommend using <quote>shorewall restart</quote>; it Also, I don&#39;t recommend using <quote><command>shorewall restart</command></quote>;
is better to create an <emphasis><ulink it is better to create an <emphasis><ulink
url="configuration_file_basics.htm#Configs">alternate configuration</ulink></emphasis> url="configuration_file_basics.htm#Configs">alternate configuration</ulink></emphasis>
and test it using the <ulink url="starting_and_stopping_shorewall.htm"><quote>shorewall and test it using the <ulink url="starting_and_stopping_shorewall.htm"><quote><command>shorewall
try</quote> command</ulink>.</para> try</command></quote> command</ulink>.</para>
</warning> </warning>
</section> </section>
@ -502,8 +380,9 @@
<appendix> <appendix>
<title>Revision History</title> <title>Revision History</title>
<para><revhistory><revision><revnumber>1.2</revnumber><date>2003-12-30</date><authorinitials>TE</authorinitials><revremark>Add <para><revhistory><revision><revnumber>1.5</revnumber><date>2003-01-05</date><authorinitials>TE</authorinitials><revremark>Standards
tip about /etc/shorewall/rfc1918 updates.</revremark></revision><revision><revnumber>1.1</revnumber><date>2003-11-15</date><authorinitials>TE</authorinitials><revremark>Initial Changes</revremark></revision><revision><revnumber>1.4</revnumber><date>2003-12-30</date><authorinitials>TE</authorinitials><revremark>Add
tip about /etc/shorewall/rfc1918 updates.</revremark></revision><revision><revnumber>1.3</revnumber><date>2003-11-15</date><authorinitials>TE</authorinitials><revremark>Initial
Docbook Conversion</revremark></revision></revhistory></para> Docbook Conversion</revremark></revision></revhistory></para>
</appendix> </appendix>
</article> </article>

217
Shorewall-docs/two-interface.xml
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@ -12,7 +12,7 @@
<surname>Eastep</surname> <surname>Eastep</surname>
</author> </author>
<pubdate>2003-12-31</pubdate> <pubdate>2003-01-06</pubdate>
<copyright> <copyright>
<year>2002</year> <year>2002</year>
@ -106,13 +106,11 @@
installed by the presence of an <command>ip</command> program on your installed by the presence of an <command>ip</command> program on your
firewall system. As <systemitem class="username">root</systemitem>, you firewall system. As <systemitem class="username">root</systemitem>, you
can use the <command>which</command> command to check for this program: can use the <command>which</command> command to check for this program:
<programlisting> <programlisting>[root@gateway root]# <command>which ip</command>
[root@gateway root]# which ip
/sbin/ip /sbin/ip
[root@gateway root]# [root@gateway root]#</programlisting> I recommend that you first read through
</programlisting> I recommend that you first read through the guide to the guide to familiarize yourself with what&#39;s involved then go back
familiarize yourself with what&#39;s involved then go back through it through it again making your configuration changes.</para>
again making your configuration changes.</para>
</section> </section>
<section> <section>
@ -195,32 +193,16 @@
<para>The <filename class="directory">/etc/shorewall/</filename><filename>policy</filename> <para>The <filename class="directory">/etc/shorewall/</filename><filename>policy</filename>
file included with the two-interface sample has the following policies: file included with the two-interface sample has the following policies:
<informaltable frame="all" label="policy file" pgwide="0"><tgroup <programlisting>#SOURCE DEST POLICY LOG LEVEL LIMIT:BURST
align="left" cols="5"><thead valign="middle"><row valign="middle"><entry loc net ACCEPT
align="left">Source Zone</entry><entry align="left">Destination Zone</entry><entry net all DROP info
align="left">Policy</entry><entry align="left">Log Level</entry><entry all all REJECT info</programlisting> In the two-interface
align="left">Limit:Burst</entry></row></thead><tbody valign="middle"><row sample, the line below is included but commented out. If you want your
valign="middle"><entry align="left"><varname>loc</varname></entry><entry firewall system to have full access to servers on the internet, uncomment
align="left"><varname>net</varname></entry><entry align="left"><varname>ACCEPT</varname></entry><entry that line. <programlisting>#SOURCE DEST POLICY LOG LEVEL LIMIT:BURST
align="left"></entry><entry align="left"></entry></row><row fw net ACCEPT</programlisting> The above policy will:
valign="middle"><entry align="left"><varname>net</varname></entry><entry <itemizedlist><listitem><para>Allow all connection requests from your
align="left"><varname>all</varname></entry><entry align="left"><varname>DROP</varname></entry><entry local network to the internet</para></listitem><listitem><para>Drop
align="left"><varname>info</varname></entry><entry align="left"></entry></row><row
valign="middle"><entry align="left"><varname>all</varname></entry><entry
align="left"><varname>all</varname></entry><entry align="left"><varname>REJECT</varname></entry><entry
align="left"><varname>info</varname></entry><entry align="left"></entry></row></tbody></tgroup></informaltable>
In the two-interface sample, the line below is included but commented out.
If you want your firewall system to have full access to servers on the
internet, uncomment that line. <informaltable frame="all"
label="policy file" pgwide="0"><tgroup align="left" cols="5"><thead
valign="middle"><row valign="middle"><entry align="left">Source Zone</entry><entry
align="left">Destination Zone</entry><entry align="left">Policy</entry><entry
align="left">Log Level</entry><entry align="left">Limit:Burst</entry></row></thead><tbody
valign="middle"><row valign="middle"><entry align="left"><varname>fw</varname></entry><entry
align="left"><varname>net</varname></entry><entry align="left"><varname>ACCEPT</varname></entry><entry
align="left"></entry><entry align="left"></entry></row></tbody></tgroup></informaltable>
The above policy will: <itemizedlist><listitem><para>Allow all connection
requests from your local network to the internet</para></listitem><listitem><para>Drop
(ignore) all connection requests from the internet to your firewall or (ignore) all connection requests from the internet to your firewall or
local network</para></listitem><listitem><para>Optionally accept all local network</para></listitem><listitem><para>Optionally accept all
connection requests from the firewall to the internet (if you uncomment connection requests from the firewall to the internet (if you uncomment
@ -310,11 +292,10 @@
network (the Internal Interface on your firewall plus your other network (the Internal Interface on your firewall plus your other
computers). <emphasis role="bold">RFC 1918</emphasis> reserves several computers). <emphasis role="bold">RFC 1918</emphasis> reserves several
<emphasis>Private</emphasis> <acronym>IP</acronym> address ranges for this <emphasis>Private</emphasis> <acronym>IP</acronym> address ranges for this
purpose: <programlisting> purpose: <programlisting>10.0.0.0 - 10.255.255.255
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255 172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255 192.168.0.0 - 192.168.255.255</programlisting> <inlinegraphic
</programlisting> <inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para> fileref="images/BD21298_.gif" format="GIF" /></para>
<para>Before starting Shorewall, you should look at the IP address of your <para>Before starting Shorewall, you should look at the IP address of your
external interface and if it is one of the above ranges, you should remove external interface and if it is one of the above ranges, you should remove
@ -460,38 +441,18 @@
<para>The general form of a simple port forwarding rule in <filename <para>The general form of a simple port forwarding rule in <filename
class="directory">/etc/shorewall/</filename><filename>rules</filename> is: class="directory">/etc/shorewall/</filename><filename>rules</filename> is:
<informaltable frame="all" label="rules" pgwide="0"><tgroup align="left" <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
cols="7"><thead valign="middle"><row valign="middle"><entry align="left">ACTION</entry><entry DNAT net loc:<emphasis>&#60;server local ip address&#62;</emphasis>[:<emphasis>&#60;server port&#62;</emphasis>] <emphasis>&#60;protocol&#62;</emphasis> <emphasis>&#60;port&#62;</emphasis></programlisting>
align="left">SOURCE</entry><entry align="left">DEST</entry><entry
align="left">PROTO</entry><entry align="left">DEST PORT(S)</entry><entry
align="left">CLIENT PORT(s)</entry><entry align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>DNAT</varname></entry><entry align="left"><varname>net</varname></entry><entry
align="left"><varname>loc:&#60;server local ip address&#62; [:&#60;server
port&#62;]</varname></entry><entry align="left"><varname>&#60;protocol&#62;</varname></entry><entry
align="left"><varname>&#60;port&#62;</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable>
<example label="1"><title>Web Server</title><para>You run a Web Server on <example label="1"><title>Web Server</title><para>You run a Web Server on
computer 2 and you want to forward incoming <acronym>TCP</acronym> port 80 computer 2 and you want to forward incoming <acronym>TCP</acronym> port 80
to that system: <informaltable frame="all" label="rules" pgwide="0"><tgroup to that system: <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
align="left" cols="7"><thead valign="middle"><row valign="middle"><entry DNAT net loc:10.10.10.2 tcp 80</programlisting></para></example>
align="left">ACTION</entry><entry align="left">SOURCE</entry><entry
align="left">DEST</entry><entry align="left">PROTO</entry><entry
align="left">DEST PORT(S)</entry><entry align="left">CLIENT PORT(S)</entry><entry
align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>DNAT</varname></entry><entry align="left"><varname>net</varname></entry><entry
align="left"><varname>loc:10.10.10.2</varname></entry><entry align="left"><varname>tcp</varname></entry><entry
align="left"><varname>80</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable></para></example>
<example label="2"><title>FTP Server</title><para>You run an <example label="2"><title>FTP Server</title><para>You run an
<acronym>FTP</acronym> Server on computer 1 so you want to forward <acronym>FTP</acronym> Server on computer 1 so you want to forward
incoming <acronym>TCP</acronym> port 21 to that system: <informaltable incoming <acronym>TCP</acronym> port 21 to that system:
frame="all" label="rules" pgwide="0"><tgroup align="left" cols="7"><thead <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
valign="middle"><row valign="middle"><entry align="left">ACTION</entry><entry DNAT net loc:10.10.10.1 tcp 21</programlisting> For
align="left">SOURCE</entry><entry align="left">DEST</entry><entry <acronym>FTP</acronym>, you will also need to have <acronym>FTP</acronym>
align="left">PROTO</entry><entry align="left">DEST PORT(S)</entry><entry
align="left">CLIENT PORT(S)</entry><entry align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>DNAT</varname></entry><entry align="left"><varname>net</varname></entry><entry
align="left"><varname>loc:10.10.10.1</varname></entry><entry align="left"><varname>tcp</varname></entry><entry
align="left"><varname>21</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable>
For <acronym>FTP</acronym>, you will also need to have <acronym>FTP</acronym>
connection tracking and <acronym>NAT</acronym> support in your kernel. For connection tracking and <acronym>NAT</acronym> support in your kernel. For
vendor-supplied kernels, this means that the <filename class="libraryfile">ip_conntrack_ftp</filename> vendor-supplied kernels, this means that the <filename class="libraryfile">ip_conntrack_ftp</filename>
and <filename class="libraryfile">ip_nat_ftp</filename> modules must be and <filename class="libraryfile">ip_nat_ftp</filename> modules must be
@ -508,15 +469,8 @@
url="FAQ.htm#faq2">Shorewall FAQ #2</ulink>.</para></listitem><listitem><para>Many url="FAQ.htm#faq2">Shorewall FAQ #2</ulink>.</para></listitem><listitem><para>Many
<acronym>ISP</acronym>s block incoming connection requests to port 80. If <acronym>ISP</acronym>s block incoming connection requests to port 80. If
you have problems connecting to your web server, try the following rule you have problems connecting to your web server, try the following rule
and try connecting to port 5000.</para></listitem></itemizedlist><informaltable and try connecting to port 5000.</para></listitem></itemizedlist><programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
frame="all" label="rules" pgwide="0"><tgroup align="left" cols="7"><thead DNAT net loc:10.10.10.2:80 tcp 5000</programlisting>
valign="middle"><row valign="middle"><entry align="left">ACTION</entry><entry
align="left">SOURCE</entry><entry align="left">DEST</entry><entry
align="left">PROTO</entry><entry align="left">DEST PORT(S)</entry><entry
align="left">CLIENT PORT(S)</entry><entry align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>DNAT</varname></entry><entry align="left"><varname>net</varname></entry><entry
align="left"><varname>loc:10.10.10.2:80</varname></entry><entry
align="left"><varname>tcp</varname></entry><entry align="left"><varname>5000</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable>
<inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para> <inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<para>At this point, modify <filename class="directory">/etc/shorewall/</filename><filename>rules</filename> <para>At this point, modify <filename class="directory">/etc/shorewall/</filename><filename>rules</filename>
@ -556,111 +510,48 @@
<acronym>UDP</acronym> and <acronym>TCP</acronym>) from the local network <acronym>UDP</acronym> and <acronym>TCP</acronym>) from the local network
to the firewall; you do that by adding the following rules in <filename to the firewall; you do that by adding the following rules in <filename
class="directory">/etc/shorewall/</filename><filename>rules</filename>. class="directory">/etc/shorewall/</filename><filename>rules</filename>.
<informaltable frame="all" label="rules" pgwide="0"><tgroup align="left" <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
cols="7"><thead valign="middle"><row valign="middle"><entry align="left">ACTION</entry><entry ACCEPT loc fw tcp 53
align="left">SOURCE</entry><entry align="left">DEST</entry><entry ACCEPT loc fw udp 53</programlisting></para></listitem></itemizedlist></para>
align="left">PROTO</entry><entry align="left">DEST PORT(S)</entry><entry
align="left">CLIENT PORT(S)</entry><entry align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>loc</varname></entry><entry
align="left"><varname>fw</varname></entry><entry align="left"><varname>tcp</varname></entry><entry
align="left"><varname>53</varname></entry><entry></entry><entry></entry></row><row><entry
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>loc</varname></entry><entry
align="left"><varname>fw</varname></entry><entry align="left"><varname>udp</varname></entry><entry
align="left"><varname>53</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable></para></listitem></itemizedlist></para>
</section> </section>
<section> <section>
<title>Other Connections</title> <title>Other Connections</title>
<para>The two-interface sample includes the following rules: <para>The two-interface sample includes the following rules:
<informaltable frame="all" label="rules" pgwide="0"><tgroup align="left" <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
cols="7"><thead valign="middle"><row valign="middle"><entry align="left">ACTION</entry><entry ACCEPT fw net tcp 53
align="left">SOURCE</entry><entry align="left">DEST</entry><entry ACCEPT fw net udp 53</programlisting>Those
align="left">PROTO</entry><entry align="left">DEST PORT(S)</entry><entry rules allow <acronym>DNS</acronym> access from your firewall and may be
align="left">CLIENT PORT(S)</entry><entry align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry removed if you uncommented the line in <filename class="directory">/etc/shorewall/</filename><filename>policy</filename>
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>fw</varname></entry><entry
align="left"><varname>net</varname></entry><entry align="left"><varname>tcp</varname></entry><entry
align="left"><varname>53</varname></entry><entry></entry><entry></entry></row><row><entry
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>fw</varname></entry><entry
align="left"><varname>net</varname></entry><entry align="left"><varname>udp</varname></entry><entry
align="left"><varname>53</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable>
Those rules allow <acronym>DNS</acronym> access from your firewall and may
be removed if you uncommented the line in <filename class="directory">/etc/shorewall/</filename><filename>policy</filename>
allowing all connections from the firewall to the internet.</para> allowing all connections from the firewall to the internet.</para>
<para>The sample also includes: <informaltable frame="all" label="rules" <para>The sample also includes: <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
pgwide="0"><tgroup align="left" cols="7"><thead valign="middle"><row ACCEPT loc fw tcp 22</programlisting> That
valign="middle"><entry align="left">ACTION</entry><entry align="left">SOURCE</entry><entry rule allows you to run an <acronym>SSH</acronym> server on your firewall
align="left">DEST</entry><entry align="left">PROTO</entry><entry and connect to that server from your local systems.</para>
align="left">DEST PORT(S)</entry><entry align="left">CLIENT PORT(S)</entry><entry
align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>loc</varname></entry><entry
align="left"><varname>fw</varname></entry><entry align="left"><varname>tcp</varname></entry><entry
align="left"><varname>22</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable>
That rule allows you to run an <acronym>SSH</acronym> server on your
firewall and connect to that server from your local systems.</para>
<para>If you wish to enable other connections between your firewall and <para>If you wish to enable other connections between your firewall and
other systems, the general format is: <informaltable frame="all" other systems, the general format is: <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
label="rules" pgwide="0"><tgroup align="left" cols="7"><thead ACCEPT fw <emphasis>&#60;destination zone&#62; &#60;protocol&#62; &#60;port&#62;</emphasis></programlisting>
valign="middle"><row valign="middle"><entry align="left">ACTION</entry><entry
align="left">SOURCE</entry><entry align="left">DEST</entry><entry
align="left">PROTO</entry><entry align="left">DEST PORT(S)</entry><entry
align="left">CLIENT PORT(S)</entry><entry align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>&#60;source
zone&#62;</varname></entry><entry align="left"><varname>&#60;destination
zone&#62;</varname></entry><entry align="left"><varname>&#60;protocol&#62;</varname></entry><entry
align="left"><varname>&#60;port&#62;</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable>
<example><title>Web Server on Firewall</title><para>You want to run a Web <example><title>Web Server on Firewall</title><para>You want to run a Web
Server on your firewall system: <informaltable frame="all" label="rules" Server on your firewall system: <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
pgwide="0"><tgroup align="left" cols="7"><colspec colname="c1" /><colspec ACCEPT net fw tcp 80
colname="c2" /><colspec colname="c3" /><colspec colname="c4" /><colspec ACCEPT loc fw tcp 80</programlisting> Those
colname="c5" /><colspec colname="c6" /><colspec colname="c7" /><thead two rules would of course be in addition to the rules listed above under
valign="middle"><row valign="middle"><entry align="left">ACTION</entry><entry <quote><link linkend="cachingdns">You can configure a Caching Name Server
align="left">SOURCE</entry><entry align="left">DEST</entry><entry on your firewall</link></quote>.</para></example> If you don&#39;t know
align="left">PROTO</entry><entry align="left">DEST PORT(S)</entry><entry what port and protocol a particular application uses, look <ulink
align="left">CLIENT PORT(S)</entry><entry align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>net</varname></entry><entry
align="left"><varname>fw</varname></entry><entry align="left"><varname>tcp</varname></entry><entry
align="left"><varname>80</varname></entry><entry nameend="c7" namest="c6">#Allow
web access from the Internet</entry></row><row><entry align="left"><varname>ACCEPT</varname></entry><entry
align="left"><varname>loc</varname></entry><entry align="left"><varname>fw</varname></entry><entry
align="left"><varname>tcp</varname></entry><entry align="left"><varname>80</varname></entry><entry
nameend="c7" namest="c6">#Allow web access from the local network</entry></row></tbody></tgroup></informaltable>
Those two rules would of course be in addition to the rules listed above
under <quote><link linkend="cachingdns">You can configure a Caching Name
Server on your firewall</link></quote>.</para></example> If you don&#39;t
know what port and protocol a particular application uses, look <ulink
url="ports.htm">here</ulink>. <important><para>I don&#39;t recommend url="ports.htm">here</ulink>. <important><para>I don&#39;t recommend
enabling <command>telnet</command> to/from the internet because it uses enabling <command>telnet</command> to/from the internet because it uses
clear text (even for login!). If you want shell access to your firewall clear text (even for login!). If you want shell access to your firewall
from the internet, use <acronym>SSH</acronym>:</para></important><informaltable from the internet, use <acronym>SSH</acronym>:</para><programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
frame="all" label="rules" pgwide="0"><tgroup align="left" cols="7"><thead ACCEPT net fw tcp 22</programlisting></important>
valign="middle"><row valign="middle"><entry align="left">ACTION</entry><entry
align="left">SOURCE</entry><entry align="left">DEST</entry><entry
align="left">PROTO</entry><entry align="left">DEST PORT(S)</entry><entry
align="left">CLIENT PORT(S)</entry><entry align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>net</varname></entry><entry
align="left"><varname>fw</varname></entry><entry align="left"><varname>tcp</varname></entry><entry
align="left"><varname>22</varname></entry><entry></entry><entry></entry></row></tbody></tgroup></informaltable>
<inlinegraphic fileref="images/leaflogo.gif" format="GIF" />Bering users <inlinegraphic fileref="images/leaflogo.gif" format="GIF" />Bering users
will want to add the following two rules to be compatible with will want to add the following two rules to be compatible with
Jacques&#39;s Shorewall configuration. <informaltable frame="all" Jacques&#39;s Shorewall configuration.<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
label="rules" pgwide="0"><tgroup align="left" cols="7"><colspec ACCEPT loc fw udp 53 #Allow DNS Cache to work
colname="c1" /><colspec colname="c2" /><colspec colname="c3" /><colspec ACCEPT loc fw tcp 80 #Allow Weblet to work</programlisting>
colname="c4" /><colspec colname="c5" /><colspec colname="c6" /><colspec
colname="c7" /><thead valign="middle"><row valign="middle"><entry
align="left">ACTION</entry><entry align="left">SOURCE</entry><entry
align="left">DEST</entry><entry align="left">PROTO</entry><entry
align="left">DEST PORT(S)</entry><entry align="left">CLIENT PORT(S)</entry><entry
align="left">ORIGINAL DEST</entry></row></thead><tbody><row><entry
align="left"><varname>ACCEPT</varname></entry><entry align="left"><varname>loc</varname></entry><entry
align="left"><varname>fw</varname></entry><entry align="left"><varname>udp</varname></entry><entry
align="left"><varname>53</varname></entry><entry nameend="c7" namest="c6">#Allow
DNS Cache to work</entry></row><row><entry align="left"><varname>ACCEPT</varname></entry><entry
align="left"><varname>loc</varname></entry><entry align="left"><varname>fw</varname></entry><entry
align="left"><varname>tcp</varname></entry><entry align="left"><varname>80</varname></entry><entry
nameend="c7" namest="c6">#Allow weblet to work</entry></row></tbody></tgroup></informaltable>
<inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para> <inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<para>Now edit your <filename class="directory">/etc/shorewall/</filename><filename>rules</filename> <para>Now edit your <filename class="directory">/etc/shorewall/</filename><filename>rules</filename>