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299
Shorewall-docs/standalone.xml
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@ -15,12 +15,10 @@
</author>
</authorgroup>
<pubdate>2003-11-15</pubdate>
<pubdate>2004-01-06</pubdate>
<copyright>
<year>2002</year>
<year>2003</year>
<year>2002-2004</year>
<holder>Thomas M. Eastep</holder>
</copyright>
@ -111,9 +109,10 @@
<section>
<title>PPTP/ADSL</title>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> 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
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<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
described in the steps below</emphasis>. ADSL with PPTP is most commonly
found in Europe, notably in Austria.</para>
@ -122,11 +121,13 @@
<section>
<title>Shorewall Concepts</title>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> The
configuration files for Shorewall are contained in the directory
/etc/shorewall -- for simple 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
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<para>The configuration files for Shorewall are contained in the directory
<filename class="directory">/etc/shorewall</filename> -- for simple
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
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
@ -160,7 +161,7 @@
</tgroup>
</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
default, the firewall itself is known as <emphasis role="bold">fw</emphasis>.</para>
@ -171,84 +172,33 @@
<itemizedlist>
<listitem>
<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>
</listitem>
<listitem>
<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>
</itemizedlist>
<para>For each connection request entering the firewall, the request is
first checked against the /etc/shorewall/rules file. If no rule in that
file matches the connection request then the first policy in
/etc/shorewall/policy that matches the request is applied. If that policy
is REJECT or DROP the request is first checked against the rules in
/etc/shorewall/common if that file exists; otherwise the rules in
/etc/shorewall/common.def are checked.</para>
first checked against the <filename><filename>/etc/shorewall/rules</filename></filename>
file. If no rule in that file matches the connection request then the
first policy in <filename>/etc/shorewall/policy</filename> that matches
the request is applied. If that policy is REJECT or DROP the request is
first checked against the rules in /etc/shorewall/common if that file
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
sample has the following policies:</para>
<para>The <filename>/etc/shorewall/policy</filename> file included with
the one-interface sample has the following policies:</para>
<table>
<title>one-interface sample /etc/shorewall/policy</title>
<tgroup cols="5">
<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>
<programlisting>#SOURCE ZONE DESTINATION ZONE POLICY LOG LEVEL LIMIT:BURST
fw net ACCEPT
net all DROP info
all all REJECT info</programlisting>
<para>The above policy will:</para>
@ -268,8 +218,8 @@
</listitem>
</orderedlist>
<para>At this point, edit your /etc/shorewall/policy and make any changes
that you wish.</para>
<para>At this point, edit your <filename>/etc/shorewall/policy</filename>
and make any changes that you wish.</para>
</section>
<section>
@ -287,12 +237,14 @@
<emphasis role="bold">ppp0</emphasis>. If you connect using ISDN, your
external interface will be <emphasis role="bold">ippp0</emphasis>.</para>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> The
Shorewall one-interface sample configuration assumes that the external
interface is <emphasis role="bold">eth0</emphasis>. If your configuration
is different, you will have to modify the sample /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>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<para>The Shorewall one-interface sample configuration assumes that the
external interface is <emphasis role="bold">eth0</emphasis>. If your
configuration is different, you will have to modify the sample
/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>
<para>If your external interface is <emphasis role="bold">ppp0</emphasis>
@ -309,9 +261,9 @@
<tip>
<para>If you specify <emphasis>norfc1918</emphasis> for your external
interface, you will want to check the <ulink url="errata.htm">Shorewall
Errata</ulink> periodically for updates to the /etc/shorewall/rfc1918
file. Alternatively, you can <ulink url="myfiles.htm#RFC1918">strip down
your /etc/shorewall/rfc1918 files as I do</ulink>.</para>
Errata</ulink> periodically for updates to the <filename>/etc/shorewall/rfc1918
file</filename>. Alternatively, you can <ulink url="myfiles.htm#RFC1918">strip
down your <filename>/etc/shorewall/rfc1918</filename> file as I do</ulink>.</para>
</tip>
</section>
@ -332,70 +284,31 @@
Translation</emphasis> to rewrite packet headers when forwarding to/from
the internet.</para>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> 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 the
<quote>norfc1918</quote> option from the entry in
/etc/shorewall/interfaces.</para>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<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
the <quote>norfc1918</quote> option from the entry in
<filename>/etc/shorewall/interfaces</filename>.</para>
</section>
<section>
<title>Enabling other Connections</title>
<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>
<title>/etc/shorewall/rules</title>
<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>
<programlisting>#ACTION SOURCE DESTINATION PROTO DEST PORT(S)
ACCEPT net fw <emphasis>&#60;protocol&#62;</emphasis> <emphasis>&#60;port&#62;</emphasis></programlisting>
<example>
<title>You want to run a Web Server and a POP3 Server on your firewall
system:</title>
<para><table><title>/etc/shorewall/rules</title><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>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>
<para><programlisting>#ACTION SOURCE DESTINATION PROTO DEST PORT(S)
ACCEPT net fw tcp 80
ACCEPT net fw tcp 110</programlisting></para>
</example>
<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
firewall from the internet, use SSH:</para>
<table>
<title>/etc/shorewall/rules</title>
<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>
<programlisting>#ACTION SOURCE DESTINATION PROTO DEST PORT(S)
ACCEPT net fw tcp 22</programlisting>
</important>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> At this
point, edit /etc/shorewall/rules to add other connections as desired.</para>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<para>At this point, edit /etc/shorewall/rules to add other connections as
desired.</para>
</section>
<section>
<title>Starting and Stopping Your Firewall</title>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /> The
<ulink url="Install.htm">installation procedure</ulink> configures your
system to start Shorewall at system boot but beginning with Shorewall
version 1.3.9 startup is disabled so that your system won&#39;t try to
start Shorewall before configuration is complete. Once you have completed
configuration of your firewall, you can enable Shorewall startup by
removing the file /etc/shorewall/startup_disabled.</para>
<para><inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<para>The <ulink url="Install.htm">installation procedure</ulink>
configures your system to start Shorewall at system boot but beginning
with Shorewall version 1.3.9 startup is disabled so that your system
won&#39;t try to start Shorewall before configuration is complete. Once
you have completed configuration of your firewall, you can enable
Shorewall startup by removing the file <filename>/etc/shorewall/startup_disabled</filename>.</para>
<important>
<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>
<para>The firewall is started using the <quote>shorewall start</quote>
command and stopped using <quote>shorewall stop</quote>. When the firewall
is stopped, routing is enabled on those hosts that have an entry in <ulink
url="Documentation.htm#Routestopped">/etc/shorewall/routestopped</ulink>.
A running firewall may be restarted using the <quote>shorewall restart</quote>
command. If you want to totally remove any trace of Shorewall from your
Netfilter configuration, use <quote>shorewall clear</quote>.</para>
<para>The firewall is started using the <quote><command>shorewall start</command></quote>
command and stopped using <quote><command>shorewall stop</command></quote>.
When the firewall is stopped, routing is enabled on those hosts that have
an entry in <filename><ulink url="Documentation.htm#Routestopped">/etc/shorewall/routestopped</ulink></filename>.
A running firewall may be restarted using the <quote><command>shorewall
restart</command></quote> command. If you want to totally remove any trace
of Shorewall from your Netfilter configuration, use <quote><command>shorewall
clear</command></quote>.</para>
<warning>
<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
entry for the IP address that you are connected from to <ulink
url="Documentation.htm#Routestopped">/etc/shorewall/routestopped</ulink>.
Also, I don&#39;t recommend using <quote>shorewall restart</quote>; it
is better to create an <emphasis><ulink
issue a <quote><command>shorewall stop</command></quote> command unless
you have added an entry for the IP address that you are connected from
to <ulink url="Documentation.htm#Routestopped"><filename>/etc/shorewall/routestopped</filename></ulink>.
Also, I don&#39;t recommend using <quote><command>shorewall restart</command></quote>;
it is better to create an <emphasis><ulink
url="configuration_file_basics.htm#Configs">alternate configuration</ulink></emphasis>
and test it using the <ulink url="starting_and_stopping_shorewall.htm"><quote>shorewall
try</quote> command</ulink>.</para>
and test it using the <ulink url="starting_and_stopping_shorewall.htm"><quote><command>shorewall
try</command></quote> command</ulink>.</para>
</warning>
</section>
@ -502,8 +380,9 @@
<appendix>
<title>Revision History</title>
<para><revhistory><revision><revnumber>1.2</revnumber><date>2003-12-30</date><authorinitials>TE</authorinitials><revremark>Add
tip about /etc/shorewall/rfc1918 updates.</revremark></revision><revision><revnumber>1.1</revnumber><date>2003-11-15</date><authorinitials>TE</authorinitials><revremark>Initial
<para><revhistory><revision><revnumber>1.5</revnumber><date>2003-01-05</date><authorinitials>TE</authorinitials><revremark>Standards
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>
</appendix>
</article>

217
Shorewall-docs/two-interface.xml
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@ -12,7 +12,7 @@
<surname>Eastep</surname>
</author>
<pubdate>2003-12-31</pubdate>
<pubdate>2003-01-06</pubdate>
<copyright>
<year>2002</year>
@ -106,13 +106,11 @@
installed by the presence of an <command>ip</command> program on your
firewall system. As <systemitem class="username">root</systemitem>, you
can use the <command>which</command> command to check for this program:
<programlisting>
[root@gateway root]# which ip
<programlisting>[root@gateway root]# <command>which ip</command>
/sbin/ip
[root@gateway root]#
</programlisting> I recommend that you first read through the guide to
familiarize yourself with what&#39;s involved then go back through it
again making your configuration changes.</para>
[root@gateway root]#</programlisting> I recommend that you first read through
the guide to familiarize yourself with what&#39;s involved then go back
through it again making your configuration changes.</para>
</section>
<section>
@ -195,32 +193,16 @@
<para>The <filename class="directory">/etc/shorewall/</filename><filename>policy</filename>
file included with the two-interface sample has the following policies:
<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>loc</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><row
valign="middle"><entry align="left"><varname>net</varname></entry><entry
align="left"><varname>all</varname></entry><entry align="left"><varname>DROP</varname></entry><entry
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
<programlisting>#SOURCE DEST POLICY LOG LEVEL LIMIT:BURST
loc net ACCEPT
net all DROP info
all all REJECT info</programlisting> 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. <programlisting>#SOURCE DEST POLICY LOG LEVEL LIMIT:BURST
fw net ACCEPT</programlisting> 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
local network</para></listitem><listitem><para>Optionally accept all
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
computers). <emphasis role="bold">RFC 1918</emphasis> reserves several
<emphasis>Private</emphasis> <acronym>IP</acronym> address ranges for this
purpose: <programlisting>
10.0.0.0 - 10.255.255.255
purpose: <programlisting>10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
</programlisting> <inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
192.168.0.0 - 192.168.255.255</programlisting> <inlinegraphic
fileref="images/BD21298_.gif" format="GIF" /></para>
<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
@ -460,38 +441,18 @@
<para>The general form of a simple port forwarding rule in <filename
class="directory">/etc/shorewall/</filename><filename>rules</filename> is:
<informaltable frame="all" label="rules" pgwide="0"><tgroup align="left"
cols="7"><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>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>
<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
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>
<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
to that system: <informaltable frame="all" label="rules" pgwide="0"><tgroup
align="left" cols="7"><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>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>
to that system: <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
DNAT net loc:10.10.10.2 tcp 80</programlisting></para></example>
<example label="2"><title>FTP Server</title><para>You run an
<acronym>FTP</acronym> Server on computer 1 so you want to forward
incoming <acronym>TCP</acronym> port 21 to that system: <informaltable
frame="all" label="rules" pgwide="0"><tgroup align="left" cols="7"><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>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>
incoming <acronym>TCP</acronym> port 21 to that system:
<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
DNAT net loc:10.10.10.1 tcp 21</programlisting> For
<acronym>FTP</acronym>, you will also need to have <acronym>FTP</acronym>
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>
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
<acronym>ISP</acronym>s block incoming connection requests to port 80. If
you have problems connecting to your web server, try the following rule
and try connecting to port 5000.</para></listitem></itemizedlist><informaltable
frame="all" label="rules" pgwide="0"><tgroup align="left" cols="7"><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>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>
and try connecting to port 5000.</para></listitem></itemizedlist><programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
DNAT net loc:10.10.10.2:80 tcp 5000</programlisting>
<inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<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
to the firewall; you do that by adding the following rules in <filename
class="directory">/etc/shorewall/</filename><filename>rules</filename>.
<informaltable frame="all" label="rules" pgwide="0"><tgroup align="left"
cols="7"><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>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>
<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
ACCEPT loc fw tcp 53
ACCEPT loc fw udp 53</programlisting></para></listitem></itemizedlist></para>
</section>
<section>
<title>Other Connections</title>
<para>The two-interface sample includes the following rules:
<informaltable frame="all" label="rules" pgwide="0"><tgroup align="left"
cols="7"><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>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>
<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
ACCEPT fw net tcp 53
ACCEPT fw net udp 53</programlisting>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>
<para>The sample also includes: <informaltable frame="all" label="rules"
pgwide="0"><tgroup align="left" cols="7"><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>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>The sample also includes: <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
ACCEPT loc fw tcp 22</programlisting> 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
other systems, the general format is: <informaltable frame="all"
label="rules" pgwide="0"><tgroup align="left" cols="7"><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>&#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>
other systems, the general format is: <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
ACCEPT fw <emphasis>&#60;destination zone&#62; &#60;protocol&#62; &#60;port&#62;</emphasis></programlisting>
<example><title>Web Server on Firewall</title><para>You want to run a Web
Server on your firewall system: <informaltable frame="all" label="rules"
pgwide="0"><tgroup align="left" cols="7"><colspec colname="c1" /><colspec
colname="c2" /><colspec colname="c3" /><colspec 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>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
Server on your firewall system: <programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
ACCEPT net fw tcp 80
ACCEPT loc fw tcp 80</programlisting> 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
enabling <command>telnet</command> to/from the internet because it uses
clear text (even for login!). If you want shell access to your firewall
from the internet, use <acronym>SSH</acronym>:</para></important><informaltable
frame="all" label="rules" pgwide="0"><tgroup align="left" cols="7"><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>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>
from the internet, use <acronym>SSH</acronym>:</para><programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
ACCEPT net fw tcp 22</programlisting></important>
<inlinegraphic fileref="images/leaflogo.gif" format="GIF" />Bering users
will want to add the following two rules to be compatible with
Jacques&#39;s Shorewall configuration. <informaltable frame="all"
label="rules" pgwide="0"><tgroup align="left" cols="7"><colspec
colname="c1" /><colspec colname="c2" /><colspec colname="c3" /><colspec
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>
Jacques&#39;s Shorewall configuration.<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
ACCEPT loc fw udp 53 #Allow DNS Cache to work
ACCEPT loc fw tcp 80 #Allow Weblet to work</programlisting>
<inlinegraphic fileref="images/BD21298_.gif" format="GIF" /></para>
<para>Now edit your <filename class="directory">/etc/shorewall/</filename><filename>rules</filename>