shorewall_code/Shorewall-docs2/myfiles.xml

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<article>
  <!--$Id$-->

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

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

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

    <pubdate>2004-08-05</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
      2.1.1. 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). 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
        dual-boots Mandrake 10.0 (Official) and Windows XP) - 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 SuSE 9.0 Linux
        system <quote>Wookie</quote>, my Wife's Windows XP system
        <quote>Tarry</quote>, and our&nbsp; dual-booting (Windows XP/SuSE 9.1)
        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 (25 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 Wookie (193.168.1.3) configured as a 3-port bridge. Squid
        runs on this system and is configured as a transparent proxy.</para>
      </listitem>
    </itemizedlist>

    <para>The firewall runs on a 256MB PII/233 with Debian Sarge
    (Testing).</para>

    <para>Wookie and Ursa run Samba and Wookie acts as a WINS server.</para>

    <para>The wireless network connects to Wookie's eth2 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.</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
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=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:/usr/local/sbin
SHOREWALL_SHELL=/bin/ash
SUBSYSLOCK=               #I run Debian which doesn't use service locks
STATEDIR=/var/state/shorewall
MODULESDIR=
FW=fw
IP_FORWARDING=On
ADD_IP_ALIASES=Yes
ADD_SNAT_ALIASES=Yes
TC_ENABLED=Yes
CLEAR_TC=No
MARK_IN_FORWARD_CHAIN=No
CLAMPMSS=Yes
ROUTE_FILTER=No
DETECT_DNAT_IPADDRS=Yes
MUTEX_TIMEOUT=60
NEWNOTSYN=Yes
BLACKLISTNEWONLY=Yes
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;
LOG=info</programlisting></para>
      </blockquote>
    </section>

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

      <blockquote>
        <programlisting>#ZONE   DISPLAY         COMMENTS
net     Internet        Internet
dmz     DMZ             Demilitarized zone
loc     Local           Local networks
tx      Texas           Peer Network in Plano
#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   INERFACE        BROADCAST       OPTIONS
net     eth0            206.124.146.255 dhcp,norfc1918,routefilter,blacklist,tcpflags,nosmurfs
loc     eth2            192.168.1.255   dhcp
dmz     eth1            -
-       texas           192.168.9.255
#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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; texas:192.168.8.0/22
#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

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

      <blockquote>
        <programlisting>#INTERFACE      HOST(S)
eth1            206.124.146.177
eth2            -
#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                                    # For testing fw-&gt;fw rules
loc             net             ACCEPT                                    # Allow all net traffic from local net
$FW             loc             ACCEPT                                    # Allow local access from the firewall
$FW             tx              ACCEPT                                    # Allow firewall access to texas
loc             tx              ACCEPT                                    # Allow local net access to texas
loc             fw              REJECT          $LOG                      # Reject loc-&gt;fw and log
net             all             DROP            $LOG            10/sec:40 # Rate limit and
                                                                          # DROP net-&gt;all
all             all             REJECT          $LOG                      # Reject and log the rest
#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 do
        my SuSE system (192.168.1.3), 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
+eth0::192.168.1.1      0.0.0.0/0       192.168.1.254
eth0:2                  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>
        <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 variable TEXAS set in
      /etc/shorewall/params)</title>

      <blockquote>
        <programlisting>#TYPE                   ZONE    GATEWAY         GATEWAY ZONE    PORT
gre                     net     $TEXAS
#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

#QUEUE		loc				net			udp
#QUEUE		loc				fw			udp
#QUEUE		loc				net			tcp
###############################################################################################################################################################################
# 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
###############################################################################################################################################################################
# Internet to DMZ 
#
DNAT-		net				dmz:206.124.146.177	tcp	smtp					-		206.124.146.179,206.124.146.178	
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:$LOG	net				dmz			tcp	32768:61000				20
###############################################################################################################################################################################
#
# Net to Local
#
# When I'm "on the road", the following two rules allow me VPN access back home.
#
DNAT		net				loc:192.168.1.4		tcp	1723	-
DNAT		net:!4.3.113.178		loc:192.168.1.4		gre	-
ACCEPT		net				loc:192.168.1.5		tcp	22
#
# ICQ
#
ACCEPT		net				loc:192.168.1.5		tcp	4000:4100
#
# Real Audio
#
ACCEPT		net 				loc:192.168.1.5		udp	6970:7170
#
# Overnet
#
#ACCEPT		net				loc:192.168.1.5		tcp	4662
#ACCEPT		net				loc:192.168.1.5		udp	12112
#
# Silently Handle common probes
#
REJECT		net				loc			tcp	www,ftp,https
###############################################################################################################################################################################
# DMZ to Internet
#
ACCEPT		dmz				net			tcp	smtp,domain,www,81,https,whois,echo,2702,21,2703,ssh,8080
ACCEPT		dmz				net			udp	domain
REJECT:$LOG     dmz                             net                     udp     1025:1031
ACCEPT		dmz				net:$POPSERVERS		tcp	pop3
#ACCEPT		dmz				net:206.191.151.2	tcp	pop3
#ACCEPT		dmz				net:66.216.26.115	tcp	pop3
#
# Something is wrong with the FTP connection tracking code or there is some client out there
# that is sending a PORT command which that code doesn't understand. Either way,
# the following works around the problem.
#
ACCEPT:$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:192.168.1.3		tcp	111
ACCEPT		dmz:206.124.146.177		loc:192.168.1.3		udp
###############################################################################################################################################################################
# Internet to Firewall
#
REJECT		net				fw			tcp	www,ftp,https
ACCEPT		net				dmz			udp	33434:33435
###############################################################################################################################################################################
# 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
###############################################################################################################################################################################
# Ping
#
ACCEPT		all				all			icmp	8
###############################################################################################################################################################################
ACCEPT		tx				loc:192.168.1.5		all
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE
</programlisting>
      </blockquote>
    </section>

    <section id="Interfaces">
      <title>/etc/network/interfaces</title>

      <blockquote>
        <para>This file is Debian specific. My additional entries(which is
        displayed in <emphasis role="bold">bold type</emphasis>) add a route
        to my DSL modem when eth0 is brought up and a route to my DMZ server
        when eth1 is brought up. It allows me to enter <quote>Yes</quote> in
        the HAVEROUTE column of <link linkend="ProxyARP">my Proxy ARP
        file</link>.</para>

        <programlisting>...
auto auto eth0
iface eth0 inet static
	address 206.124.146.176
	netmask 255.255.255.0
	network 206.124.146.0
	broadcast 206.124.146.255
	gateway 206.124.146.254
	<emphasis role="bold">up ip route add 192.168.1.1 dev eth0</emphasis>

eth1
iface eth1 inet static
        address 206.124.146.176
        netmask 255.255.255.255
        broadcast 0.0.0.0
        <emphasis role="bold">up ip route add 206.124.146.177 dev eth1
</emphasis>...</programlisting>
      </blockquote>
    </section>
  </section>

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

    <para>As mentioned above, Wookie 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>
        <programlisting>#ZONE   DISPLAY         COMMENTS
net     Net             Internet
loc     Local           Local networks
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
fw              fw              ACCEPT
loc             net             ACCEPT
net             loc             ACCEPT
net             fw              ACCEPT
loc             fw              ACCEPT
loc             WiFi            ACCEPT
fw              WiFi            ACCEPT
fw              net             ACCEPT
fw              loc             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
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>hosts</title>

      <blockquote>
        <programlisting>#ZONE           HOST(S)                         OPTIONS
net             br0:eth1
loc             br0:eth0
WiFi            br0:eth2                        maclist
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS LINE -- DO NOT REMOVE</programlisting>
      </blockquote>
    </section>

    <section>
      <title>rules</title>

      <blockquote>
        <para>The first rule allows a transparent WWW proxy (Squid) to run on
        my bridge/firewall. Squid listens on port 3128.</para>

        <para>The remaining rules protect the local systems and bridge from
        the WiFi network. Note that we don't restrict WiFi→net traffic since
        the only directly-accessible system in the net zone is the firewall
        (Wookie and the Firewall are connected by a cross-over cable).</para>

        <programlisting>#ACTION    SOURCE          DEST            PROTO   DEST    SOURCE  ORIGINAL
#                                          PORT            PORT(S) DEST
REDIRECT   loc             3128            tcp     www     -       !192.168.1.0/24

ACCEPT     WiFi            loc             udp     137:139
ACCEPT     WiFi            loc             tcp     22,80,137,139,445,901,3389
ACCEPT     WiFi            loc             udp     1024:                                   137
ACCEPT     WiFi            loc             udp     177

ACCEPT     loc             WiFi            udp     137:139
ACCEPT     loc             WiFi            tcp     137,139,445
ACCEPT     loc             WiFi            udp     1024:                                   137
ACCEPT     loc             WiFi            tcp     6000:6010

ACCEPT     WiFi            fw              tcp     ssh,137,139,445
ACCEPT     WiFi            fw              udp     137:139,445
ACCEPT     WiFi            fw              udp     1024:                                   137
ACCEPT     WiFi            fw              udp     ntp

#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:eth2                00:A0:1C:DB:0C:A0       192.168.1.7     #Work Laptop
br0:eth2                00:04:59:0e:85:b9                       #WAP11
br0:eth2                00:06:D5:45:33:3c                       #WET11
br0:eth2                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
        disbributions would be similar.</para>

        <programlisting>#!/bin/sh
################################################################################
#   Script to create a bridge between eth0, eth1 and eth2
#
#     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
#
# chkconfig: 2345 05 89
# description: Layer 2 Bridge
#
################################################################################

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

do_stop() {
    echo "Stopping Bridge"
    brctl delbr br0
    ip link set eth0 down
    ip link set eth1 down
    ip link set eth2 down
}

do_start() {

      echo "Starting Bridge"
      ip link set eth0 up
      ip link set eth1 up
      ip link set eth2 up
      brctl addbr br0
      brctl addif br0 eth0
      brctl addif br0 eth1
      brctl addif br0 eth2
}

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='static'
BROADCAST='192.168.1.255'
IPADDR='192.168.1.3'
NETWORK='192.168.1.0'
NETMASK='255.255.255.0'
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 - 255.255.255.0 br0
default 192.168.1.254 - -</programlisting>
      </blockquote>
    </section>
  </section>
</article>