forked from extern/shorewall_code
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git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@800 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
320 lines
13 KiB
HTML
320 lines
13 KiB
HTML
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<html>
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<meta http-equiv="Content-Language" content="en-us">
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<meta name="GENERATOR" content="Microsoft FrontPage 5.0">
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content="text/html; charset=windows-1252">
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<title>Starting and Stopping Shorewall</title>
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</head>
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<body>
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<div style="text-align: center;">
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<h1>Starting/Stopping and Monitoring the Firewall<br>
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</h1>
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</div>
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<p><br>
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If you have a permanent internet connection such as DSL or Cable, I
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recommend that you start the firewall automatically at boot. Once you
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have installed "firewall" in your init.d directory, simply type
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"chkconfig --add firewall". This will start the firewall in run levels
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2-5 and stop it in run levels 1 and 6. If you want to configure your
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firewall differently from this default, you can
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use the "--level" option in chkconfig (see "man chkconfig") or using
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your favorite graphical run-level editor.</p>
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<p><strong><u> <font color="#000099"> Important Notes:</font></u></strong><br>
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</p>
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<ol>
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<li>Shorewall startup is disabled by default. Once you have
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configured your firewall, you can enable startup by removing the
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file /etc/shorewall/startup_disabled. Note: Users of the .deb package
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must edit /etc/default/shorewall and set 'startup=1'.<br>
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</li>
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<li>If you use dialup, you may want to start the firewall in your
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/etc/ppp/ip-up.local script. I recommend just placing "shorewall
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restart" in that script.</li>
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</ol>
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<p> </p>
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<p> You can manually start and stop Shoreline Firewall using the
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"shorewall" shell program. Please refer to the <a
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href="starting_and_stopping_shorewall.htm#StateDiagram">Shorewall
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State Diagram</a> is shown at the bottom of this page. </p>
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<ul>
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<li>shorewall start - starts the firewall</li>
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<li>shorewall stop - stops the firewall; the only traffic permitted
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through the firewall is from systems listed in
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/etc/shorewall/routestopped
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(Beginning with version 1.4.7, if ADMINISABSENTMINDED=Yes in
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/etc/shorewall/shorewall.conf
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then in addition, all existing connections are permitted and any new
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connections
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originating from the firewall itself are allowed).</li>
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<li>shorewall restart - stops the firewall (if it's running) and then
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starts it again</li>
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<li>shorewall reset - reset the packet and byte counters in the
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firewall</li>
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<li>shorewall clear - remove all rules and chains installed by
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Shoreline Firewall. The firewall is "wide open"</li>
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<li>shorewall refresh - refresh the rules involving
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the broadcast addresses of firewall interfaces, <a
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href="blacklisting_support.htm">the black list</a>, <a
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href="traffic_shaping.htm">traffic control rules</a> and <a
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href="ECN.html">ECN control rules</a>.</li>
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</ul>
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If you include the keyword <i>debug</i> as the first argument, then a
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shell trace of the command is produced as in:<br>
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<pre> <font color="#009900"><b>shorewall debug start 2> /tmp/trace</b></font><br></pre>
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<p>The above command would trace the 'start' command and place the
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trace information
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in the file /tmp/trace<br>
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</p>
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<p>Beginning with version 1.4.7, shorewall can give detailed help about
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each of its commands:<br>
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</p>
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<ul>
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<li>shorewall help [ <i>command</i> | host | address ]<br>
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</li>
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</ul>
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<p>The "shorewall" program may also be used to monitor the firewall.</p>
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<ul>
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<li>shorewall status - produce a verbose report about the firewall
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(iptables -L -n -v)</li>
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<li>shorewall show <i>chain</i>1 [ <span style="font-style: italic;">chain2
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... </span>] - produce a verbose
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report about the listed <i>chains </i>(iptables -L <i>chain</i>
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-n -v) <span style="font-weight: bold;">Note: </span>You may only
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list one chain in the <span style="font-weight: bold;">show</span>
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command when running Shorewall version 1.4.6 and earlier. Version
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1.4.7 and later allow you to list multiple chains in one command.<br>
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</li>
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<li>shorewall show nat - produce a verbose report about the nat table
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(iptables -t nat -L -n -v)</li>
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<li>shorewall show tos - produce a verbose report about the mangle
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table (iptables -t mangle -L -n -v)</li>
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<li>shorewall show log - display the last 20 packet
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log entries.</li>
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<li>shorewall show connections - displays the IP connections
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currently being tracked by the firewall.</li>
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<li>shorewall show tc - displays information about the traffic
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control/shaping configuration.</li>
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<li>shorewall monitor [ delay ] - Continuously display the firewall
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status, last 20 log entries and nat. When the log entry display
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changes, an audible alarm is sounded.</li>
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<li>shorewall hits - Produces several reports about
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the Shorewall packet log messages in the current /var/log/messages file.</li>
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<li>shorewall version - Displays the installed version number.</li>
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<li>shorewall check - Performs a <u>cursory</u> validation of the
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zones, interfaces, hosts, rules and policy files.<br>
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<br>
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<font size="4" color="#ff6666"><b>The "check" command is totally
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unsuppored and does not parse and validate the generated iptables
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commands. Even though the "check" command completes successfully,
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the configuration may fail to start. Problem reports that complain
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about
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errors that the 'check' command does not detect will not be accepted.<br>
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<br>
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See the recommended way to make configuration changes described below.</b></font><br>
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<br>
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</li>
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<li>shorewall try<i> configuration-directory</i> [<i> timeout</i> ] -
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Restart shorewall using the specified configuration and if an error
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occurs or if the<i> timeout </i> option is given
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and the new configuration has been up for that many seconds then
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shorewall is restarted using the standard configuration.</li>
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<li>shorewall logwatch (added in version 1.3.2) - Monitors the <a
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href="#Conf">LOGFILE </a>and produces an audible alarm when new
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Shorewall messages are logged.</li>
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</ul>
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Beginning with Shorewall 1.4.6, /sbin/shorewall supports a couple of
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commands for dealing with IP addresses and IP address ranges:<br>
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<ul>
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<li>shorewall ipcalc [ <i>address mask </i>| <i>address/vlsm</i> ]
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- displays the network address, broadcast address, network in CIDR
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notation and netmask corresponding to the input[s].</li>
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<li>shorewall iprange <i>address1-address2</i> - Decomposes the
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specified range of IP addresses into the equivalent list of
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network/host addresses. <br>
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</li>
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</ul>
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There is a set of commands dealing with <a
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href="blacklisting_support.htm">dynamic blacklisting</a>:<br>
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<ul>
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<li>shorewall drop <i><ip address list> </i>- causes packets
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from the listed IP addresses to be silently dropped by the firewall.</li>
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<li>shorewall reject <i><ip address list> </i>- causes
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packets from the listed IP addresses to be rejected by the firewall.</li>
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<li>shorewall allow <i><ip address list> </i>- re-enables
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receipt of packets from hosts previously blacklisted by a <i>drop</i>
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or <i>reject</i> command.</li>
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<li>shorewall save - save the dynamic blacklisting configuration so
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that it will be automatically restored the next time that the firewall
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is restarted.</li>
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<li>show dynamic - displays the dynamic blacklisting chain.<br>
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</li>
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</ul>
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Finally, the "shorewall" program may be used to dynamically alter the
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contents of a zone.<br>
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<ul>
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<li>shorewall add <i>interface</i>[:<i>host]</i> <i>zone </i>-
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Adds the specified interface (and host if included) to the specified
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zone.</li>
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<li>shorewall delete <i>interface</i>[:<i>host]</i> <i>zone </i>-
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Deletes the specified interface (and host if included) from the
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specified zone.</li>
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</ul>
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<blockquote>Examples:<br>
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<blockquote><font color="#009900"><b>shorewall add ipsec0:192.0.2.24
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vpn1</b></font> -- adds the address 192.0.2.24 from interface ipsec0 to
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the zone vpn1<br>
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<font color="#009900"><b> shorewall delete ipsec0:192.0.2.24 vpn1</b></font>
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-- deletes the address 192.0.2.24 from interface ipsec0 from zone vpn1<br>
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</blockquote>
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</blockquote>
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<p> The <b>shorewall start</b>, <b>shorewall restart, shorewall
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check, </b>and <b>shorewall try </b>commands allow you to specify
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which <a href="configuration_file_basics.htm#Configs"> Shorewall
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configuration</a> to use:</p>
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<blockquote>
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<p> shorewall [ -c <i>configuration-directory</i> ]
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{start|restart|check}<br>
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shorewall try <i>configuration-directory</i></p>
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</blockquote>
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<p> If a <i>configuration-directory</i> is specified, each time that
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Shorewall is going to use a file in /etc/shorewall it will first look
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in the <i>configuration-directory</i> . If the file is present in the <i>configuration-directory</i>,
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that file will be used; otherwise, the file in /etc/shorewall will be
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used.</p>
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<p> When changing the configuration of a production firewall, I
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recommend the following:</p>
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<ul>
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<li><font color="#009900"><b>mkdir /etc/test</b></font></li>
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<li><font color="#009900"><b>cd /etc/test</b></font></li>
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<li><copy any files that you need to change from /etc/shorewall to
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. and change them here></li>
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<li><font color="#009900"><b>shorewall -c . check</b></font></li>
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<li><correct any errors found by check and check again></li>
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<li><font color="#009900"><b>/sbin/shorewall try .</b></font></li>
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</ul>
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<p> If the configuration starts but doesn't work, just "shorewall
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restart" to restore the old configuration. If the new configuration
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fails to start, the "try" command will automatically start the old one
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for you.</p>
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<p> When the new configuration works then just </p>
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<ul>
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<li><font color="#009900"><b>cp * /etc/shorewall</b></font></li>
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<li><font color="#009900"><b>cd</b></font></li>
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<li><font color="#009900"><b>rm -rf /etc/test</b></font></li>
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</ul>
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<p><a name="StateDiagram"></a>The Shorewall State Diargram is depicted
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below.<br>
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</p>
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<div align="center"><img src="images/State_Diagram.png"
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alt="(State Diagram)" width="747" height="714" align="middle"> <br>
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</div>
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<p> <br>
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</p>
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You will note that the commands that result in state transitions use
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the word "firewall" rather than "shorewall". That is because the actual
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transitions are done by /usr/share/shorewall/firewall; /sbin/shorewall
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runs 'firewall" according to the following table:<br>
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<br>
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<table cellpadding="2" cellspacing="2" border="1">
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<tbody>
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<tr>
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<td valign="top"><u><b>/sbin/shorewall Command</b><br>
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</u></td>
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<td valign="top"><u><b>Resulting /usr/share/shorewall/firewall
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Command</b><br>
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</u></td>
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<td valign="top"><u><b>Effect if the Command Succeeds</b><br>
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</u></td>
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</tr>
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<tr>
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<td valign="top">shorewall start<br>
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</td>
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<td valign="top">firewall start<br>
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</td>
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<td valign="top">The system filters packets based on your current
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Shorewall Configuration<br>
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</td>
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</tr>
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<tr>
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<td valign="top">shorewall stop<br>
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</td>
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<td valign="top">firewall stop<br>
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</td>
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<td valign="top">Only traffic to/from hosts listed in
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/etc/shorewall/hosts is passed to/from/through the firewall. For
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Shorewall versions beginning
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with 1.4.7, if ADMINISABSENTMINDED=Yes in /etc/shorewall/shorewall.conf
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then
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in addition, all existing connections are retained and all connection
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requests
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from the firewall are accepted.<br>
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</td>
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</tr>
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<tr>
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<td valign="top">shorewall restart<br>
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</td>
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<td valign="top">firewall restart<br>
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</td>
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<td valign="top">Logically equivalent to "firewall stop;firewall
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start"<br>
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</td>
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</tr>
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<tr>
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<td valign="top">shorewall add<br>
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</td>
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<td valign="top">firewall add<br>
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</td>
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<td valign="top">Adds a host or subnet to a dynamic zone<br>
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</td>
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</tr>
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<tr>
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<td valign="top">shorewall delete<br>
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</td>
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<td valign="top">firewall delete<br>
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</td>
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<td valign="top">Deletes a host or subnet from a dynamic zone<br>
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</td>
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</tr>
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<tr>
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<td valign="top">shorewall refresh<br>
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</td>
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<td valign="top">firewall refresh<br>
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</td>
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<td valign="top">Reloads rules dealing with static blacklisting,
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traffic control and ECN.<br>
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</td>
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</tr>
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<tr>
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<td valign="top">shorewall clear<br>
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</td>
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<td valign="top">firewall clear<br>
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</td>
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<td valign="top">Removes all Shorewall rules, chains, addresses,
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routes and ARP entries.<br>
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</td>
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</tr>
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<tr>
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<td valign="top">shorewall try<br>
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</td>
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<td valign="top">firewall -c <new configuration> restart<br>
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If unsuccessful then firewall start (standard configuration)<br>
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If timeout then firewall restart (standard configuration)<br>
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</td>
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<td valign="top"><br>
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</td>
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</tr>
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</tbody>
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</table>
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<br>
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<p><font size="2"> Updated 8/25/2003 - <a href="support.htm">Tom Eastep</a>
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</font></p>
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<p><font face="Trebuchet MS"><a href="copyright.htm"><font size="2">Copyright</font>
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<EFBFBD> <font size="2">2001, 2002, 2003 Thomas M. Eastep.</font></a></font><br>
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</p>
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<br>
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</body>
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</html>
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