shorewall_code/Shorewall-docs/starting_and_stopping_shorewall.htm
2003-07-07 14:18:52 +00:00

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<title>Starting and Stopping Shorewall</title>
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<h1 align="center"><font color="#ffffff">Starting/Stopping and Monitoring
the Firewall</font></h1>
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<p> If you have a permanent internet connection such as DSL or Cable,
I recommend that you start the firewall automatically at boot.
Once you have installed "firewall" in your init.d directory, simply
type "chkconfig --add firewall". This will start the firewall
in run levels 2-5 and stop it in run levels 1 and 6. If you want to
configure your firewall differently from this default, you can use
the "--level" option in chkconfig (see "man chkconfig") or using your
favorite graphical run-level editor.</p>
<p><strong><u> <font color="#000099"> Important Notes:</font></u></strong><br>
</p>
<ol>
<li>Shorewall startup is disabled by default. Once you have
configured your firewall, you can enable startup by removing the file
/etc/shorewall/startup_disabled. Note: Users of the .deb package must
edit /etc/default/shorewall and set 'startup=1'.<br>
</li>
<li>If you use dialup, you may want to start the firewall
in your /etc/ppp/ip-up.local script. I recommend just placing "shorewall
restart" in that script.</li>
</ol>
<p> </p>
<p> You can manually start and stop Shoreline Firewall using the "shorewall"
shell program: </p>
<ul>
<li>shorewall start - starts the firewall</li>
<li>shorewall stop - stops the firewall</li>
<li>shorewall restart - stops the firewall (if it's
running) and then starts it again</li>
<li>shorewall reset - reset the packet and byte counters
in the firewall</li>
<li>shorewall clear - remove all rules and chains installed
by Shoreline Firewall</li>
<li>shorewall refresh - refresh the rules involving the
broadcast addresses of firewall interfaces, <a
href="blacklisting_support.htm">the black list</a>, <a
href="traffic_shaping.htm">traffic control rules</a> and <a
href="ECN.html">ECN control rules</a>.</li>
</ul>
If you include the keyword <i>debug</i> as the first argument, then
a shell trace of the command is produced as in:<br>
<pre> <font color="#009900"><b>shorewall debug start 2&gt; /tmp/trace</b></font><br></pre>
<p>The above command would trace the 'start' command and place the trace information
in the file /tmp/trace<br>
</p>
<p>The <a href="#StateDiagram">Shorewall State Diagram</a> is shown at the
bottom of this page.<br>
</p>
<p>The "shorewall" program may also be used to monitor the firewall.</p>
<ul>
<li>shorewall status - produce a verbose report about the
firewall (iptables -L -n -v)</li>
<li>shorewall show <i>chain</i> - produce a verbose report
about <i>chain </i>(iptables -L <i>chain</i> -n -v)</li>
<li>shorewall show nat - produce a verbose report about
the nat table (iptables -t nat -L -n -v)</li>
<li>shorewall show tos - produce a verbose report about
the mangle table (iptables -t mangle -L -n -v)</li>
<li>shorewall show log - display the last 20 packet log
entries.</li>
<li>shorewall show connections - displays the IP connections
currently being tracked by the firewall.</li>
<li>shorewall show
tc - displays
information about the traffic control/shaping configuration.</li>
<li>shorewall monitor [ delay ] - Continuously display the
firewall status, last 20 log entries and nat. When the log
entry display changes, an audible alarm is sounded.</li>
<li>shorewall hits - Produces several reports about the
Shorewall packet log messages in the current /var/log/messages
file.</li>
<li>shorewall version - Displays the installed version
number.</li>
<li>shorewall check - Performs a <u>cursory</u> validation of the
zones, interfaces, hosts, rules and policy files.<br>
<br>
<font size="4" color="#ff6666"><b>The "check" command is totally unsuppored
and does not parse and validate the generated iptables commands.
Even though the "check" command completes successfully, the configuration
may fail to start. Problem reports that complain about errors that the 'check'
command does not detect will not be accepted.<br>
<br>
See the recommended way to make configuration changes described below.</b></font><br>
<br>
</li>
<li>shorewall try<i> configuration-directory</i> [<i> timeout</i>
] - Restart shorewall using the specified configuration and if
an error occurs or if the<i> timeout </i> option is given and the
new configuration has been up for that many seconds then shorewall
is restarted using the standard configuration.</li>
<li>shorewall deny, shorewall reject, shorewall accept and
shorewall save implement <a href="blacklisting_support.htm">dynamic
blacklisting</a>.</li>
<li>shorewall logwatch (added in version 1.3.2) - Monitors
the <a href="#Conf">LOGFILE </a>and produces an audible alarm when
new Shorewall messages are logged.</li>
</ul>
Beginning with Shorewall 1.4.6, /sbin/shorewall supports a couple of commands
for dealing with IP addresses and IP address ranges:<br>
<ul>
<li>shorewall ipcalc [ <i>address mask </i>| <i>address/vlsm</i> ] - displays
the network address, broadcast address, network in CIDR notation and netmask
corresponding to the input[s].</li>
<li>shorewall iprange <i>address1-address2</i> - Decomposes the specified
range of IP addresses into the equivalent list of network/host addresses.
<br>
</li>
</ul>
Finally, the "shorewall" program may be used to dynamically alter the
contents of a zone.<br>
<ul>
<li>shorewall add <i>interface</i>[:<i>host]</i> <i>zone </i>-
Adds the specified interface (and host if included) to the specified zone.</li>
<li>shorewall delete <i>interface</i>[:<i>host]</i> <i>zone
</i>- Deletes the specified interface (and host if included) from
the specified zone.</li>
</ul>
<blockquote>Examples:<br>
<blockquote><font color="#009900"><b>shorewall add ipsec0:192.0.2.24 vpn1</b></font>
-- adds the address 192.0.2.24 from interface ipsec0 to the zone vpn1<br>
<font color="#009900"><b> shorewall delete ipsec0:192.0.2.24
vpn1</b></font> -- deletes the address 192.0.2.24 from interface ipsec0
from zone vpn1<br>
</blockquote>
</blockquote>
<p> The <b>shorewall start</b>, <b>shorewall restart, shorewall check, </b>and
<b>shorewall try </b>commands allow you to specify which <a
href="configuration_file_basics.htm#Configs"> Shorewall configuration</a>
to use:</p>
<blockquote>
<p> shorewall [ -c <i>configuration-directory</i> ] {start|restart|check}<br>
shorewall try <i>configuration-directory</i></p>
</blockquote>
<p> If a <i>configuration-directory</i> is specified, each time that Shorewall
is going to use a file in /etc/shorewall it will first look in the
<i>configuration-directory</i> . If the file is present in the <i>configuration-directory</i>,
that file will be used; otherwise, the file in /etc/shorewall will be
used.</p>
<p> When changing the configuration of a production firewall, I recommend
the following:</p>
<ul>
<li><font color="#009900"><b>mkdir /etc/test</b></font></li>
<li><font color="#009900"><b>cd /etc/test</b></font></li>
<li>&lt;copy any files that you need to change
from /etc/shorewall to . and change them here&gt;</li>
<li><font color="#009900"><b>shorewall -c . check</b></font></li>
<li>&lt;correct any errors found by check and check again&gt;</li>
<li><font
color="#009900"><b>/sbin/shorewall try .</b></font></li>
</ul>
<p> If the configuration starts but doesn't work, just "shorewall restart"
to restore the old configuration. If the new configuration fails to
start, the "try" command will automatically start the old one for you.</p>
<p> When the new configuration works then just </p>
<ul>
<li><font color="#009900"><b>cp * /etc/shorewall</b></font></li>
<li><font color="#009900"><b>cd</b></font></li>
<li><font color="#009900"><b>rm -rf /etc/test</b></font></li>
</ul>
<p><a name="StateDiagram"></a>The Shorewall State Diargram is depicted below.<br>
</p>
<div align="center"><img src="images/State_Diagram.png"
alt="(State Diagram)" width="747" height="714" align="middle">
<br>
</div>
<p><EFBFBD> <br>
</p>
You will note that the commands that result in state transitions
use the word "firewall" rather than "shorewall". That is because the actual
transitions are done by /usr/lib/shorewall/firewall (/usr/share/shorewall/firewall
on Debian); /sbin/shorewall runs 'firewall" according to the following
table:<br>
<br>
<table cellpadding="2" cellspacing="2" border="1">
<tbody>
<tr>
<td valign="top">shorewall start<br>
</td>
<td valign="top">firewall start<br>
</td>
</tr>
<tr>
<td valign="top">shorewall stop<br>
</td>
<td valign="top">firewall stop<br>
</td>
</tr>
<tr>
<td valign="top">shorewall restart<br>
</td>
<td valign="top">firewall restart<br>
</td>
</tr>
<tr>
<td valign="top">shorewall add<br>
</td>
<td valign="top">firewall add<br>
</td>
</tr>
<tr>
<td valign="top">shorewall delete<br>
</td>
<td valign="top">firewall delete<br>
</td>
</tr>
<tr>
<td valign="top">shorewall refresh<br>
</td>
<td valign="top">firewall refresh<br>
</td>
</tr>
<tr>
<td valign="top">shorewall try<br>
</td>
<td valign="top">firewall -c &lt;new configuration&gt; restart<br>
If unsuccessful then firewall start (standard configuration)<br>
If timeout then firewall restart (standard configuration)<br>
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<br>
<p><font size="2"> Updated 7/6/2003 - <a href="support.htm">Tom Eastep</a>
</font></p>
<p><font face="Trebuchet MS"><a href="copyright.htm"><font size="2">Copyright</font>
<20> <font size="2">2001, 2002, 2003 Thomas M. Eastep.</font></a></font><br>
</p>
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