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<body class="article toc2 toc-right">
<div id="header">
<h1>Iptables with shorewall!</h1>
<div class="details">
<span id="author" class="author">Apostolos rootApostolos@swarmlab.io</span><br>
</div>
<div id="toc" class="toc2">
<div id="toctitle">Table of Contents</div>
<ul class="sectlevel1">
<li><a href="#cheat-Docker">1. Install swarmlab-sec (Home PC)</a></li>
<li><a href="#_shorewall">2. shorewall</a>
<ul class="sectlevel2">
<li><a href="#_installation">2.1. Installation</a></li>
</ul>
</li>
<li><a href="#_basic_two_interface_firewall">3. Basic Two-Interface Firewall</a></li>
<li><a href="#_shorewall_concepts">4. Shorewall Concepts</a>
<ul class="sectlevel2">
<li><a href="#_zones_shorewall_zone_declaration_file">4.1. zones — Shorewall zone declaration file</a></li>
<li><a href="#_interfaces_shorewall_interfaces_file">4.2. interfaces — Shorewall interfaces file</a></li>
<li><a href="#_policy_shorewall_policy_file">4.3. policy — Shorewall policy file</a></li>
<li><a href="#_rules_shorewall_rules_file">4.4. rules — Shorewall rules file</a></li>
<li><a href="#_compile_then_execute">4.5. Compile then Execute</a></li>
</ul>
</li>
<li><a href="#_three_interface_firewall">5. Three-Interface Firewall</a>
<ul class="sectlevel2">
<li><a href="#_zones">5.1. zones</a></li>
<li><a href="#_interfaces">5.2. interfaces</a></li>
<li><a href="#_policy">5.3. policy</a></li>
<li><a href="#_rules">5.4. rules</a></li>
<li><a href="#_masq_shorewall_masqueradesnat_definition_file">5.5. masq - Shorewall Masquerade/SNAT definition file</a></li>
<li><a href="#_snat_shorewall_snatmasquerade_definition_file">5.6. snat — Shorewall SNAT/Masquerade definition file</a></li>
<li><a href="#_compile_and_execute">5.7. Compile and Execute</a></li>
</ul>
</li>
</ul>
</div>
</div>
<div id="content">
<div id="preamble">
<div class="sectionbody">
<div class="paragraph">
<p><br></p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="cheat-Docker">1. Install swarmlab-sec (Home PC)</h2>
<div class="sectionbody">
<div class="paragraph">
<p>HowTo: See <a href="http://docs.swarmlab.io/lab/sec/sec.adoc.html" class="bare">http://docs.swarmlab.io/lab/sec/sec.adoc.html</a></p>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
<div class="title">NOTE</div>
<div class="paragraph">
<p>Assuming you&#8217;re already logged in</p>
</div>
</td>
</tr>
</table>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_shorewall">2. shorewall</h2>
<div class="sectionbody">
<div class="paragraph">
<p><strong>Shorewall</strong> is an open source firewall tool for Linux that builds upon the Netfilter (iptables/ipchains) system built into the Linux kernel, making it easier to manage more complex configuration schemes by providing a higher level of abstraction for describing rules using text files.</p>
</div>
<div class="paragraph">
<p><a href="https://en.wikipedia.org/wiki/Shorewall">More: wikipedia</a></p>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
<div class="title">NOTE</div>
<div class="paragraph">
<p>Our docker instances have only one nic</p>
</div>
<div class="paragraph">
<p>to add more nic&#8217;s:</p>
</div>
<div class="listingblock">
<div class="title">create netowrk frist</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">docker network create --driver=bridge --subnet=192.168.0.0/16 net1
docker network create --driver=bridge --subnet=192.168.0.0/16 net2
docker network create --driver=bridge --subnet=192.168.0.0/16 net3</code></pre>
</div>
</div>
<div class="paragraph">
<p>then connect network to container</p>
</div>
<div class="listingblock">
<div class="title">connect network created to container</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">docker network connect net1 master
docker network connect net1 worker1
docker network connect net2 master
docker network connect net2 worker2</code></pre>
</div>
</div>
<div class="paragraph">
<p>now let&#8217;s look at the following image</p>
</div>
</td>
</tr>
</table>
</div>
<div class="sect2">
<h3 id="_installation">2.1. Installation</h3>
<div class="paragraph">
<p>Shorewall is already installed on swarmlab-sec.</p>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_basic_two_interface_firewall">3. Basic Two-Interface Firewall</h2>
<div class="sectionbody">
<div class="imageblock">
<div class="content">
<img src="data:image/png;base64,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
</div>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
<div class="title">connect to master first</div>
<div class="paragraph">
<p>Assuming you&#8217;re already logged in master!</p>
</div>
<div class="paragraph">
<p>master is now our Firewall/Router</p>
</div>
<div class="paragraph">
<p>swarmlab-sec login</p>
</div>
</td>
</tr>
</table>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_shorewall_concepts">4. Shorewall Concepts</h2>
<div class="sectionbody">
<div class="paragraph">
<p>The configuration files for Shorewall are contained in the directory /etc/shorewall</p>
</div>
<div class="sect2">
<h3 id="_zones_shorewall_zone_declaration_file">4.1. zones — Shorewall zone declaration file</h3>
<div class="paragraph">
<p>The /etc/shorewall/zones file declares your network zones. You specify the hosts in each zone through entries in /etc/shorewall/interfaces</p>
</div>
<div class="listingblock">
<div class="title">/etc/shorewall/zones</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#ZONE TYPE OPTIONS IN_OPTIONS OUT_OPTIONS
fw firewall
net ipv4
loc ipv4</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_interfaces_shorewall_interfaces_file">4.2. interfaces — Shorewall interfaces file</h3>
<div class="paragraph">
<p>The interfaces file serves to define the firewall&#8217;s network interfaces to Shorewall.</p>
</div>
<div class="listingblock">
<div class="title">/etc/shorewall/interfaces</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#ZONE INTERFACE BROADCAST OPTIONS
net eth0 dhcp,routefilter
loc eth1 detect</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_policy_shorewall_policy_file">4.3. policy — Shorewall policy file</h3>
<div class="paragraph">
<p>This file defines the high-level policy for connections between zone</p>
</div>
<div class="listingblock">
<div class="title">/etc/shorewall/policy</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#SOURCE DEST POLICY LOGLEVEL LIMIT
loc net ACCEPT
net all DROP info
all all REJECT info</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_rules_shorewall_rules_file">4.4. rules — Shorewall rules file</h3>
<div class="paragraph">
<p>Entries in this file govern connection establishment by defining exceptions to the policies</p>
</div>
<div class="listingblock">
<div class="title">/etc/shorewall/rules</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#ACTION SOURCE DEST PROTO DPORT
ACCEPT $FW net udp 53
ACCEPT net $FW udp 53
ACCEPT $FW net tcp 80
ACCEPT net $FW tcp 80</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_compile_then_execute">4.5. Compile then Execute</h3>
<div class="paragraph">
<p>Shorewall uses a "compile" then "execute" approach. The Shorewall configuration compiler reads the configuration files and generates a shell script. Errors in the compilation step cause the script to be discarded and the command to be aborted. If the compilation step doesn&#8217;t find any errors then the shell script is executed.</p>
</div>
<div class="listingblock">
<div class="title">/sbin/shorewall</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">/sbin/shorewall start
/sbin/shorewall stop
/sbin/shorewall clear</code></pre>
</div>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
<div class="title">NOTE</div>
<div class="paragraph">
<p>The 'compiled' scripts are placed by default in the directory /var/lib/shorewall and are named to correspond to the command being executed. For example, the command /sbin/shorewall start will generate a script named /var/lib/shorewall/.start and, if the compilation is error free, that script will then be executed. If the script executes successfully, it then copies itself to /var/lib/shorewall/firewall. When an /sbin/shorewall stop or /sbin/shorewall clear command is subsequently executed, /var/lib/shorewall/firewall is run to perform the requested operation.</p>
</div>
<div class="paragraph">
<p>The AUTOMAKE option in /etc/shorewall/shorewall.conf may be set to automatically generate a new script when one of the configuration files is changed. When no file has changed since the last compilation, the /sbin/shorewall start, /sbin/shorewall reload and /sbin/shorewall restart commands will simply execute the current /var/lib/shorewall/firewall script.</p>
</div>
</td>
</tr>
</table>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_three_interface_firewall">5. Three-Interface Firewall</h2>
<div class="sectionbody">
<div class="imageblock">
<div class="content">
<img src="data:image/png;base64,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
</div>
</div>
<div class="sect2">
<h3 id="_zones">5.1. zones</h3>
<div class="listingblock">
<div class="title">/etc/shorewall/zones</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#ZONE TYPE OPTIONS IN_OPTIONS OUT_OPTIONS
fw firewall
net ipv4
loc ipv4
dmz ipv4 #new line</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_interfaces">5.2. interfaces</h3>
<div class="listingblock">
<div class="title">/etc/shorewall/interfaces</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#ZONE INTERFACE BROADCAST OPTIONS
net eth0 dhcp,routefilter
loc eth1 detect
dmz eth2 detect #new line</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_policy">5.3. policy</h3>
<div class="listingblock">
<div class="title">/etc/shorewall/policy</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#SOURCE DEST POLICY LOGLEVEL LIMIT
loc net ACCEPT
dmz net DROP #new line
net all DROP info
all all REJECT info</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_rules">5.4. rules</h3>
<div class="listingblock">
<div class="title">/etc/shorewall/rules</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#ACTION SOURCE DEST PROTO DPORT
ACCEPT $FW net udp 53
ACCEPT net $FW udp 53
ACCEPT $FW net tcp 80
ACCEPT net $FW tcp 80
#New lines
ACCEPT $FW dmz udp 53
ACCEPT dmz $FW udp 53
ACCEPT $FW dmz tcp 80
ACCEPT dmz $FW tcp 80
ACCEPT loc dmz tcp 80 # Add your rules for the zones you have defined.
ACCEPT dmz loc tcp 80 #
ACCEPT loc net tcp 80 # This here is an example
ACCEPT net loc tcp 80 # for communication
ACCEPT dmz net tcp 80 # over port 80
ACCEPT net dmz tcp 80 # aka the web</code></pre>
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</div>
<div class="sect2">
<h3 id="_masq_shorewall_masqueradesnat_definition_file">5.5. masq - Shorewall Masquerade/SNAT definition file</h3>
<div class="paragraph">
<p>/etc/shorewall/masq - directs the firewall where to use many-to-one (dynamic) Network Address Translation (a.k.a. Masquerading) and Source Network Address Translation (SNAT).</p>
</div>
<div class="listingblock">
<div class="title">/etc/shorewall/masq</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#INTERFACE SOURCE ADDRESS PROTO DPORT
eth0 eth1
eth0 eth2</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_snat_shorewall_snatmasquerade_definition_file">5.6. snat — Shorewall SNAT/Masquerade definition file</h3>
<div class="paragraph">
<p>This file is used to define dynamic NAT (Masquerading) and to define Source NAT (SNAT). It superseded shorewall-masq(5) in Shorewall 5.0.14.</p>
</div>
<div class="listingblock">
<div class="title">/etc/shorewall/masq</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">#ACTION SOURCE DEST
MASQUERADE 192.168.0.0/24 eth0
MASQUERADE 192.168.1.0/24 eth0</code></pre>
</div>
</div>
<div class="ulist">
<ul>
<li>
<p>You have a simple masquerading setup where eth0 connects to internet and eth1 connects to your local network with subnet 192.168.0.0/24.</p>
</li>
<li>
<p>You add a router to your local network to connect subnet 192.168.1.0/24 which you also want to masquerade. You then add a second entry for eth0 to this file</p>
</li>
</ul>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
<div class="paragraph">
<p>Beginning with that release, the Shorewall compiler will automatically convert existing masq files to the equivalent snat file, and rename the masq file to masq.bak.</p>
</div>
</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="_compile_and_execute">5.7. Compile and Execute</h3>
<div class="listingblock">
<div class="title">/sbin/shorewall</div>
<div class="content">
<pre class="highlight"><code class="language-bash" data-lang="bash">/sbin/shorewall start
/sbin/shorewall stop
/sbin/shorewall clear</code></pre>
</div>
</div>
<div class="paragraph">
<p><br>
<br>
</p>
</div>
<hr>
</div>
</div>
</div>
</div>
<div id="footer">
<div id="footer-text">
Last updated 2020-07-09 15:06:14 UTC
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