shorewall_code/Shorewall-docs2/myfiles.xml

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  <!--$Id$-->

  <articleinfo>
    <title>About My Network</title>

    <authorgroup>
      <author>
        <firstname>Tom</firstname>

        <surname>Eastep</surname>
      </author>
    </authorgroup>

    <pubdate>2004-10-02</pubdate>

    <copyright>
      <year>2001-2004</year>

      <holder>Thomas M. Eastep</holder>
    </copyright>

    <legalnotice>
      <para>Permission is granted to copy, distribute and/or modify this
      document under the terms of the GNU Free Documentation License, Version
      1.2 or any later version published by the Free Software Foundation; with
      no Invariant Sections, with no Front-Cover, and with no Back-Cover
      Texts. A copy of the license is included in the section entitled
      <quote><ulink url="GnuCopyright.htm">GNU Free Documentation
      License</ulink></quote>.</para>
    </legalnotice>
  </articleinfo>

  <section>
    <title>My Current Network</title>

    <caution>
      <para>I use a combination of One-to-one NAT and Proxy ARP, neither of
      which are relevant to a simple configuration with a single public IP
      address. If you have just a single public IP address, most of what you
      see here won't apply to your setup so beware of copying parts of this
      configuration and expecting them to work for you. What you copy may or
      may not work for you.</para>
    </caution>

    <caution>
      <para>The configuration shown here corresponds to Shorewall version
      2.1.7. My configuration uses features not available in earlier Shorewall
      releases.</para>
    </caution>

    <para>I have DSL service and have 5 static IP addresses
    (206.124.146.176-180). My DSL <quote>modem</quote> (Westell 2200) is
    connected to eth0 and has IP address 192.168.1.1 (factory default). The
    modem is configured in <quote>bridge</quote> mode so PPPoE is not
    involved. I have a local network connected to eth2 (subnet 192.168.1.0/24)
    and a DMZ connected to eth1 (206.124.146.176/32). Note that I configure
    the same IP address on both <filename class="devicefile">eth0</filename>
    and <filename class="devicefile">eth1</filename>.</para>

    <para>In this configuration:</para>

    <itemizedlist>
      <listitem>
        <para>I use one-to-one NAT for Ursa (my personal system that run SuSE
        9.1) - Internal address 192.168.1.5 and external address
        206.124.146.178.</para>
      </listitem>

      <listitem>
        <para>I use one-to-one NAT for EastepLaptop (My work system -- Windows
        XP SP1). Internal address 192.168.1.7 and external address
        206.124.146.180.</para>
      </listitem>

      <listitem>
        <para>I use SNAT through 206.124.146.179 for&nbsp;my Wife's Windows XP
        system <quote>Tarry</quote>, and our&nbsp; dual-booting (SuSE
        9.1/Windows XP) laptop <quote>Tipper</quote> which connects through
        the Wireless Access Point (wap) via a Wireless Bridge (wet).<note>
            <para>While the distance between the WAP and where I usually use
            the laptop isn't very far (50 feet or so), using a WAC11 (CardBus
            wireless card) has proved very unsatisfactory (lots of lost
            connections). By replacing the WAC11 with the WET11 wireless
            bridge, I have virtually eliminated these problems (Being an old
            radio tinkerer (K7JPV), I was also able to eliminate the
            disconnects by hanging a piece of aluminum foil on the family room
            wall. Needless to say, my wife Tarry rejected that as a permanent
            solution :-).</para>
          </note></para>
      </listitem>
    </itemizedlist>

    <itemizedlist>
      <listitem>
        <para>I have Ursa (193.168.1.5/206.124.146.178) configured as a 2-port
        bridge.</para>
      </listitem>

      <listitem>
        <para>Squid runs on the firewall and is configured as a transparent
        proxy.</para>
      </listitem>
    </itemizedlist>

    <para>The firewall runs on a 384MB K-6/II with SuSE 9.1.</para>

    <para>Ursa runs Samba for file sharing with the Windows systems..</para>

    <para>The wireless network connects to Ursa's eth0 via a LinkSys
    WAP11.&nbsp; In additional to using the rather weak WEP 40-bit encryption
    (64-bit with the 24-bit preamble), I use <ulink
    url="MAC_Validation.html">MAC verification</ulink>. This is still a weak
    combination and if I lived near a wireless <quote>hot spot</quote>, I
    would probably add IPSEC or something similar to my WiFi-&gt;local
    connections.</para>

    <para>The single system in the DMZ (address 206.124.146.177) runs postfix,
    Courier IMAP (imaps and pop3), DNS, a Web server (Apache) and an FTP
    server (Pure-ftpd) under Fedora Core 2. The system also runs fetchmail to
    fetch our email from our old and current ISPs. That server is managed
    through Proxy ARP.</para>

    <para>The firewall system itself runs a DHCP server that serves the local
    network.</para>

    <para>All administration and publishing is done using ssh/scp. I have a
    desktop environment installed on the firewall but I am not usually logged
    in to it. X applications tunnel through SSH to Ursa. The server also has a
    desktop environment installed and that desktop environment is available
    via XDMCP from the local zone. For the most part though, X tunneled
    through SSH is used for server administration and the server runs at run
    level 3 (multi-user console mode on Fedora).</para>

    <para>I run an SNMP server on my firewall to serve <ulink
    url="http://www.ee.ethz.ch/~oetiker/webtools/mrtg/">MRTG</ulink> running
    in the DMZ.</para>

    <para>The ethernet interface in the Server is configured with IP address
    206.124.146.177, netmask 255.255.255.0. The server's default gateway is
    206.124.146.254 (Router at my ISP. This is the same default gateway used
    by the firewall itself). On the firewall, an entry in my
    /etc/network/interfaces file (see below) adds a host route to
    206.124.146.177 through eth1 when that interface is brought up.</para>

    <para>Tarry (192.168.1.4) runs a PPTP server for Road Warrior access from
    my work laptop and the Firewall is configured with IPSEC for tunnel mode
    access from our second home in <ulink
    url="http://www.omakchamber.com/">Omak, Washington</ulink>.</para>

    <para><graphic align="center" fileref="images/network.png" /></para>
  </section>

  <section>
    <title>Firewall Configuration</title>

    <section>
      <title>Shorewall.conf</title>

      <blockquote>
        <programlisting>LOGFILE=/var/log/messages
LOGFORMAT="Shorewall:%s:%s "
LOGRATE=
LOGBURST=
LOGUNCLEAN=$LOG
BLACKLIST_LOGLEVEL=
LOGNEWNOTSYN=$LOG
MACLIST_LOG_LEVEL=$LOG
TCP_FLAGS_LOG_LEVEL=$LOG
RFC1918_LOG_LEVEL=$LOG
SMURF_LOG_LEVEL=
PATH=/usr/local/sbin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin
SHOREWALL_SHELL=/bin/ash
SUBSYSLOCK=
STATEDIR=/var/state/shorewall
MODULESDIR=
CONFIG_PATH=/etc/shorewall:/etc/shorewall/actiondir:/usr/share/shorewall
RESTOREFILE=standard
FW=fw
IP_FORWARDING=On
ADD_IP_ALIASES=Yes
ADD_SNAT_ALIASES=Yes
TC_ENABLED=Yes
CLEAR_TC=Yes
MARK_IN_FORWARD_CHAIN=No
CLAMPMSS=Yes
ROUTE_FILTER=No
DETECT_DNAT_IPADDRS=Yes
MUTEX_TIMEOUT=60
NEWNOTSYN=Yes
BLACKLISTNEWONLY=Yes
DYNAMIC_ZONES=No
DISABLE_IPV6=Yes
PKTTYPE=No
BLACKLIST_DISPOSITION=DROP
MACLIST_DISPOSITION=REJECT
TCP_FLAGS_DISPOSITION=DROP
</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Params File (Edited)</title>

      <blockquote>
        <para><programlisting>MIRRORS=&lt;list of shorewall mirror ip addresses&gt;
NTPSERVERS=&lt;list of the NTP servers I sync with&gt;
TEXAS=&lt;ip address of gateway in Plano&gt;
OMAK=&lt;ip address of tipper while we are at our second home&gt;
LOG=info
EXT_IF=eth1
INT_IF=eth0
DMZ_IF=eth2</programlisting></para>
      </blockquote>
    </section>

    <section>
      <title>Zones File</title>

      <blockquote>
        <programlisting>#ZONE   DISPLAY         COMMENTS
omak    Omak            Our Laptop at our second home
net     Internet        Internet
dmz     DMZ             Demilitarized zone
loc     Local           Local networks
tx      Texas           Peer Network in Dallas
#LAST LINE - ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE
</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Interfaces File</title>

      <blockquote>
        <para>This is set up so that I can start the firewall before bringing
        up my Ethernet interfaces.</para>

        <programlisting>#ZONE   INTERFACE BROADCAST       OPTIONS
net     $EXT_IF   206.124.146.255 dhcp,norfc1918,routefilter,blacklist,tcpflags,nosmurfs
loc     $INT_IF   192.168.1.255   dhcp
dmz     $DMZ_IF   -
-       texas     -
#LAST LINE - ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Hosts File</title>

      <blockquote>
        <programlisting>#ZONE           HOST(S)                 OPTIONS
tx              texas:192.168.8.0/22
omak            $EXT_IF:$OMAK
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Ipsec File</title>

      <blockquote>
        <programlisting>#ZONE   IPSEC   OPTIONS                 IN                      OUT
#       ONLY                            OPTIONS                 OPTIONS
omak    yes     mode=tunnel
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE
</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Routestopped File</title>

      <blockquote>
        <programlisting>#INTERFACE      HOST(S)
$DMZ_IF         206.124.146.177
$INT_IF         -
$EXT_IF         $OMAK
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Blacklist File (Partial)</title>

      <blockquote>
        <programlisting>#ADDRESS/SUBNET         PROTOCOL        PORT
0.0.0.0/0               udp             1434
0.0.0.0/0               tcp             1433
0.0.0.0/0               tcp             3127
0.0.0.0/0               tcp             8081
0.0.0.0/0               tcp             57
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>RFC1918 File</title>

      <blockquote>
        <para>Because my DSL modem has an RFC 1918 address (192.168.1.1) and
        is connected to eth0, I need to make an exception for that address in
        my rfc1918 file. I copied /usr/share/shorewall/rfc1918 to
        /etc/shorewall/rfc1918 and changed it as follows:</para>

        <programlisting>#SUBNET			TARGET
<emphasis role="bold">192.168.1.1		RETURN</emphasis>
172.16.0.0/12		logdrop		# RFC 1918
192.168.0.0/16		logdrop		# RFC 1918
10.0.0.0/8		logdrop		# RFC 1918
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE
</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Policy File</title>

      <blockquote>
        <programlisting>#SOURCE         DESTINATION     POLICY          LOG LEVEL       BURST:LIMIT
fw              fw              ACCEPT
loc             net             ACCEPT
fw              sec             ACCEPT
omak            fw              ACCEPT
fw              omak            ACCEPT
omak            loc             ACCEPT
loc             omak            ACCEPT
omak            net             NONE
net             omak            NONE
omak            dmz             NONE
dmz             omak            NONE
omak            tx              NONE
tx              omak            NONE
$FW             loc             ACCEPT          #Firewall to Local
$FW             tx              ACCEPT
loc             tx              ACCEPT
loc             fw              REJECT          $LOG
dmz             tx              ACCEPT
net             all             DROP            $LOG            10/sec:40
all             all             REJECT          $LOG
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Masq File</title>

      <blockquote>
        <para>Although most of our internal systems use one-to-one NAT, my
        wife's system (192.168.1.4) uses IP Masquerading (actually SNAT) as
        does our laptop (192.168.3.8) and visitors with laptops.</para>

        <para>The first entry allows access to the DSL modem and uses features
        introduced in Shorewall 2.1.1. The leading plus sign ("+_") causes the
        rule to be placed before rules generated by the /etc/shorewall/nat
        file below. The double colons ("::") causes the entry to be exempt
        from ADD_SNAT_ALIASES=Yes in my shorewall.conf file above.</para>

        <programlisting>#INTERFACE              SUBNET          ADDRESS
+$EXT_IF::192.168.1.1      0.0.0.0/0       192.168.1.254
$EXT_IF:2                  eth2            206.124.146.179
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS LINE -- DO NOT REMOVE
</programlisting>
      </blockquote>
    </section>

    <section>
      <title>NAT File</title>

      <blockquote>
        <programlisting>#EXTERNAL       INTERFACE       INTERNAL        ALL INTERFACES          LOCAL
206.124.146.178 eth0:0          192.168.1.5     No                      No
206.124.146.180 eth0:1          192.168.1.7     No                      No
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS LINE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section id="ProxyARP">
      <title>Proxy ARP File</title>

      <blockquote>
        <para>I configure the host route to 206.124.146.177 on <filename
        class="devicefile">eth1</filename> using the Yast2 Network Interface
        tool; the <quote>Gateway</quote> is specified as 0.0.0.0 which
        indicates that the host is directly attached to the LAN on that
        interface.</para>

        <programlisting>#ADDRESS                INTERFACE       EXTERNAL        HAVEROUTE          PERSISTENT
206.124.146.177         eth1            eth0            Yes
192.168.1.1             eth0            eth2            yes # Allow access to DSL modem from the local zone
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Tunnels File (Shell variables TEXAS and OMAK set in
      /etc/shorewall/params)</title>

      <blockquote>
        <programlisting>#TYPE                   ZONE    GATEWAY         GATEWAY ZONE    PORT
gre                     net     $TEXAS
ipsec:noah              net     $OMAK           omak
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section id="Actions">
      <title>Actions File</title>

      <blockquote>
        <programlisting>#ACTION
Mirrors             #Accept traffic from the Shorewall Mirror sites
#LAST LINE - ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>action.Mirrors File</title>

      <blockquote>
        <para>The $MIRRORS variable expands to a list of approximately 10 IP
        addresses. So moving these checks into a separate chain reduces the
        number of rules that most net-&gt;dmz traffic needs to
        traverse.</para>

        <programlisting>#TARGET  SOURCE         DEST            PROTO   DEST    SOURCE     ORIGINAL     RATE
#                                               PORT    PORT(S)    DEST         LIMIT
ACCEPT   $MIRRORS                      
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>/etc/shorewall/action.Drop</title>

      <blockquote>
        <para>This is my common action for the DROP policy. It is like the
        standard <emphasis role="bold">Drop</emphasis> action except that it
        allows <quote>Ping</quote>.</para>

        <programlisting>#TARGET  SOURCE     DEST          PROTO   DEST      SOURCE      RATE         USER/
#                                         PORT(S)   PORT(S)     LIMIT        GROUP
RejectAuth
AllowPing
dropBcast
DropSMB
DropUPnP
dropNotSyn
DropDNSrep</programlisting>
      </blockquote>
    </section>

    <section>
      <title>/etc/shorewall/action.Reject</title>

      <blockquote>
        <para>This is my common action for the REJECT policy. It is like the
        standard <emphasis role="bold">Reject</emphasis> action except that it
        allows <quote>Ping</quote> and contains one rule that guards against
        log flooding by broken software running in my local zone.</para>

        <programlisting>#TARGET  SOURCE     DEST          PROTO   DEST      SOURCE      RATE         USER/
#                                         PORT(S)   PORT(S)     LIMIT        GROUP
RejectAuth
AllowPing
dropBcast
RejectSMB
DropUPnP
dropNotSyn
DropDNSrep
DROP      loc:eth2:!192.168.1.0/24       #So that my braindead Windows[tm] XP system doesn't flood my log
                                         #with NTP requests with a source address in 16.0.0.0/8 (address of
                                         #its PPTP tunnel to HP).</programlisting>
      </blockquote>
    </section>

    <section>
      <title>Rules File (The shell variables are set in
      /etc/shorewall/params)</title>

      <blockquote>
        <programlisting>###############################################################################################################################################################################
#RESULT         CLIENT(S)                       SERVER(S)               PROTO   PORT(S)                                 CLIENT          ORIGINAL        RATE    USER
#                                                                                                                       PORT(S)         DEST:SNAT               SET
###############################################################################################################################################################################
# Local Network to Internet - Reject attempts by Trojans to call home, direct SMTP and MS Message Service
#
RejectSMTP      loc                             net                     tcp     25
REJECT:$LOG     loc                             net                     tcp     6667,25
REJECT:$LOG     loc                             net                     udp     1025:1031
#
# Stop NETBIOS crap since our policy is ACCEPT
#
REJECT          loc                             net                     tcp     137,445
REJECT          loc                             net                     udp     137:139
#
DROP            loc:!192.168.1.0/24             net
#
# SQUID
#
REDIRECT        loc                             3128                    tcp     80
###############################################################################################################################################################################
# Local Network to Firewall
#
DROP            loc:!192.168.1.0/24             fw
ACCEPT          loc                             fw                      tcp     ssh,time
ACCEPT          loc                             fw                      udp     161,ntp
###############################################################################################################################################################################
# Local Network to DMZ
#
DROP            loc:!192.168.1.0/24             dmz
ACCEPT          loc                             dmz                     udp     domain,xdmcp
ACCEPT          loc                             dmz                     tcp     www,smtp,smtps,domain,ssh,imap,https,imaps,cvspserver,ftp,10027,pop3    -
###############################################################################################################################################################################
# Internet to ALL -- drop NewNotSyn packets
#
dropNotSyn      net             fw              tcp
dropNotSyn      net             loc             tcp
dropNotSyn      net             dmz             tcp

#
# Drop ping to firewall and local
#

DropPing        net             fw
DropPing        net             loc
###############################################################################################################################################################################
# Internet to DMZ
#
DNAT-           net                             dmz:206.124.146.177     tcp     smtp                                    -               206.124.146.179,206.124.146.1
78
ACCEPT          net                             dmz                     tcp     smtp,smtps,www,ftp,imaps,domain,https,cvspserver        -
ACCEPT          net                             dmz                     udp     domain
ACCEPT          net                             dmz                     udp     33434:33436
Mirrors         net                             dmz                     tcp     rsync
ACCEPT          net:$OMAK                       dmz                     tcp     22      #SSH from Omak
AllowPing       net                             dmz
###############################################################################################################################################################################
#
# Net to Local
#
# When I'm "on the road", the following two rules allow me VPN access back home.
#
DNAT            net                             loc:192.168.1.4         tcp     1723    -
DNAT            net:!$TEXAS                     loc:192.168.1.4         gre     -
ACCEPT          net                             loc:192.168.1.5         tcp     22
#
# ICQ
#
ACCEPT          net                             loc:192.168.1.5         tcp     4000:4100
DNAT            net                             loc:192.168.1.8         tcp     4000:4100                               -               206.124.146.179
#
# Real Audio
#
ACCEPT          net                             loc:192.168.1.5         udp     6970:7170
#
# Overnet
#
#ACCEPT         net                             loc:192.168.1.5         tcp     4662
#ACCEPT         net                             loc:192.168.1.5         udp     12112
#
# Silently Handle common probes
#
REJECT          net                             loc                     tcp     www,ftp,https
###############################################################################################################################################################################
# DMZ to Internet
#
ACCEPT          dmz                             net                     tcp     smtp,domain,www,81,https,whois,echo,2702,21,2703,ssh,8080
ACCEPT          dmz                             net                     udp     domain
REJECT:$LOG     dmz                             net                     udp     1025:1031
ACCEPT          dmz                             net:$POPSERVERS         tcp     pop3
#
# Something is wrong with the FTP connection tracking code or there is some client out there
# that is sending a PORT command which that code doesn't understand. Either way,
# the following works around the problem.
#
ACCEPT:$LOG     dmz                             net                     tcp     1024:                                   20
###############################################################################################################################################################################
# DMZ to Firewall -- ntp &amp; snmp, Silently reject Auth
#
ACCEPT          dmz                             fw                      udp     ntp                                     ntp
ACCEPT          dmz                             fw                      tcp     161,ssh
ACCEPT          dmz                             fw                      udp     161
REJECT          dmz                             fw                      tcp     auth
###############################################################################################################################################################################
# DMZ to Local Network
#
ACCEPT          dmz                             loc                     tcp     smtp,6001:6010
ACCEPT          dmz:206.124.146.177             loc:192.168.1.5         tcp     111
ACCEPT          dmz:206.124.146.177             loc:192.168.1.5         udp
###############################################################################################################################################################################
# Internet to Firewall
#
REJECT          net                             fw                      tcp     www,ftp,https
ACCEPT          net                             dmz                     udp     33434:33435
ACCEPT          net:$OMAK                       fw                      udp     ntp
ACCEPT          net:$OMAK                       fw                      tcp     22      #SSH from Omak
###############################################################################################################################################################################
# Firewall to Internet
#
ACCEPT          fw                              net:$NTPSERVERS         udp     ntp                                     ntp
#ACCEPT         fw                              net:$POPSERVERS         tcp     pop3
ACCEPT          fw                              net                     udp     domain
ACCEPT          fw                              net                     tcp     domain,www,https,ssh,1723,whois,1863,ftp,2702,2703,7
ACCEPT          fw                              net                     udp     33435:33535
ACCEPT          fw                              net                     icmp
REJECT:$LOG     fw                              net                     udp     1025:1031
DROP            fw                              net                     udp     ntp
###############################################################################################################################################################################
# Firewall to DMZ
#
ACCEPT          fw                              dmz                     tcp     www,ftp,ssh,smtp
ACCEPT          fw                              dmz                     udp     domain
REJECT          fw                              dmz                     udp     137:139
###############################################################################################################################################################################
ACCEPT          tx                              loc:192.168.1.5         all
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE
</programlisting>
      </blockquote>
    </section>
  </section>

  <section>
    <title>Bridge (Ursa) Configuration</title>

    <para>As mentioned above, Ursa acts as a bridge. It's view of the network
    is diagrammed in the following figure.</para>

    <graphic fileref="images/network1.png" />

    <para>I've included the files that I used to configure that system -- some
    of them are SuSE-specific.</para>

    <para>The configuration on Wookie can be modified to test various bridging
    features -- otherwise, it serves to isolate the Wireless network from the
    rest of our systems.</para>

    <section>
      <title>shorewall.conf</title>

      <blockquote>
        <para>Only the changes from the defaults are shown.</para>

        <programlisting>BRIDGING=Yes</programlisting>
      </blockquote>
    </section>

    <section>
      <title>zones</title>

      <blockquote>
        <para>Because <emphasis role="bold">loc</emphasis> is a sub-zone of
        <emphasis role="bold">net</emphasis>, <emphasis
        role="bold">loc</emphasis> must be defined first.</para>

        <programlisting>#ZONE   DISPLAY         COMMENTS
loc     Local           Local networks
net     Internet        The Big Bad Internet
WiFi    Wireless        Wireless Network
#LAST LINE - ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE
</programlisting>
      </blockquote>
    </section>

    <section>
      <title>policy</title>

      <blockquote>
        <programlisting>#SOURCE         DEST            POLICY          LOG             LIMIT:BURST
loc             fw              ACCEPT
loc             net             NONE
loc             WiFi            ACCEPT
net             fw              ACCEPT
net             WiFi            ACCEPT
net             loc             NONE
WiFi            net             ACCEPT
fw              all             ACCEPT
#
# THE FOLLOWING POLICY MUST BE LAST
#
all             all             REJECT          info
#LAST LINE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>interfaces</title>

      <blockquote>
        <programlisting>#ZONE    INTERFACE      BROADCAST       OPTIONS
-        br0            192.168.1.255   dhcp
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>hosts</title>

      <blockquote>
        <programlisting>#ZONE           HOST(S)                         OPTIONS
loc             br0:eth1:192.168.1.0/24
net             br0:eth1
WiFi            br0:eth0                        maclist
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS LINE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>rules</title>

      <blockquote>
        <programlisting>#ACTION    SOURCE          DEST            PROTO   DEST    SOURCE  ORIGINAL
#                                          PORT            PORT(S) DEST
ACCEPT          WiFi            loc                     udp     137:139
ACCEPT          WiFi            loc                     tcp     22,80,137,139,445,631,901,3389
ACCEPT          WiFi            loc                     udp     1024:                                   137
ACCEPT          WiFi            loc                     udp     177,123
ACCEPT          WiFi            loc:192.168.1.4         tcp     1723
ACCEPT          WiFi            loc:192.168.1.4         47
ACCEPT          WiFi            loc                     tcp     5900:5909

ACCEPT          WiFi            fw                      tcp     ssh,80,111,137,139,445,9100:9104
ACCEPT          WiFi            fw                      udp
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>routestopped</title>

      <blockquote>
        <programlisting>#INTERFACE      HOST(S)         OPTIONS
br0             0.0.0.0/0       routeback
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>maclist</title>

      <blockquote>
        <programlisting>#INTERFACE              MAC                     IP ADDRESSES (Optional)
br0:eth0                00:A0:1C:DB:0C:A0       192.168.1.7     #Work Laptop
br0:eth0                00:04:59:0e:85:b9                       #WAP11
br0:eth0                00:06:D5:45:33:3c                       #WET11
br0:eth0                00:0b:c1:53:cc:97       192.168.1.8     #TIPPER
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS LINE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>/etc/init.d/bridge</title>

      <blockquote>
        <para>This file is SuSE-specific and creates the bridge device
        <filename class="devicefile">br0</filename>. A script for other
        distributions would be similar (see the <ulink
        url="bridge.html">Shorewall Bridge documentation</ulink> for
        examples).</para>

        <programlisting>#!/bin/sh
################################################################################
#   Script to create a bridge
#
#     This program is under GPL [http://www.gnu.org/copyleft/gpl.htm]
#
#     (c) 2004 - Tom Eastep (teastep@shorewall.net)
#
#   Modify the following variables to match your configuration
#
#### BEGIN INIT INFO
# Provides:       bridge
# Required-Start: coldplug
# Required-Stop:
# Default-Start:  2 3 5
# Default-Stop:   0 1 6
# Description:    starts and stops a bridge
### END INIT INFO
#
# chkconfig: 2345 05 89
# description: Layer 2 Bridge
#
################################################################################

PATH=$PATH:/sbin:/usr/sbin:/usr/local/sbin

INTERFACES="eth0 eth1"
BRIDGE="br0"

do_stop() {
    echo "Stopping Bridge $BRIDGE"
    brctl delbr $BRIDGE
    for interface in $INTERFACES; do
        ip link set $interface down
    done
}

do_start() {

      echo "Starting Bridge $BRIDGE"
      for interface in $INTERFACES; do
          ip link set $interface up
      done

      brctl addbr $BRIDGE

      for interface in $INTERFACES; do
          brctl addif $BRIDGE $interface
      done
}

case "$1" in
  start)
      do_start
    ;;
  stop)
      do_stop
    ;;
  restart)
      do_stop
      sleep 1
      do_start
    ;;
  *)
    echo "Usage: $0 {start|stop|restart}"
    exit 1
esac
exit 0</programlisting>
      </blockquote>
    </section>

    <section>
      <title>/etc/sysconfig/network/ifcfg-br0</title>

      <blockquote>
        <para>This file is SuSE-specific</para>

        <programlisting>BOOTPROTO='dhcp'
REMOTE_IPADDR=''
STARTMODE='onboot'
UNIQUE='3hqH.MjuOqWfSZ+C'
WIRELESS='no'
MTU=''</programlisting>
      </blockquote>
    </section>

    <section>
      <title>/etc/sysconfig/network/routes</title>

      <blockquote>
        <para>This file is SuSE-specific</para>

        <programlisting>192.168.1.0/24 dev br0  proto kernel  scope link  src 192.168.1.5
127.0.0.0/8 dev lo  scope link
default via 192.168.1.254 dev br0</programlisting>
      </blockquote>
    </section>
  </section>
</article>