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<blockquote> </blockquote>
<h1 style="text-align: center;">About My Network<br>
</h1>
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<h1><font size="4"> <a href="http://www.opera.com"></a> <a
href="http://www.hp.com"> </a></font></h1>
<h1>My Current Network</h1>
<font size="4"> <a href="http://www.opera.com"></a><a
href="http://www.hp.com"> </a></font>
<h1> </h1>
<blockquote>
<p><big><font color="#ff0000"><b>Warning 1: </b></font><b><small>I</small></b></big><big><b><small>
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.</small></b></big><big><b><small>
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 in your configuration.<br>
</small></b></big></p>
<p><big><b><small><big><font color="#ff0000">Warning 2: </font><small>The
configuration shown here corresponds to Shorewall version 1.4.9. It may
use features not available in earlier Shorewall releases.</small></big></small></b></big><br>
</p>
<p> I have DSL service and have 5 static IP addresses
(206.124.146.176-180). My DSL "modem" (<a href="http://www.fujitsu.com">Fujitsu</a>
Speedport) is connected to eth0. I have a local network connected to
eth2 (subnet 192.168.1.0/24), a DMZ connected to eth1 (192.168.2.0/24)
and a Wireless network connected to eth3 (192.168.3.0/24).</p>
<p> I use:<br>
</p>
<ul>
<li>One-to-one NAT for Ursa (my XP System that dual-boots Mandrake
9.2) - Internal address
192.168.1.5 and external address 206.124.146.178.</li>
<li>One-to-one NAT for EastepLaptop (My work system). Internal
address
192.168.1.7 and external address 206.124.146.180.<br>
</li>
<li>SNAT through 206.124.146.179 for&nbsp; my Linux system
(Wookie), my Wife's system (Tarry), and our&nbsp;
laptop
(Tipper) which connects through the Wireless Access Point (wap) via
a Wireless Bridge (bridge). <b><br>
<br>
Note:</b> 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 :-).</li>
</ul>
<p> The firewall runs on a 256MB PII/233 with RH9.0.</p>
<p> Wookie and the Firewall both run Samba and the Firewall acts as a
WINS
server.<br>
</p>
<p>Wookie is in its own 'whitelist' zone called 'me' which is
embedded
in the local zone.</p>
<p>The wireless network connects to eth3 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 <a href="MAC_Validation.html">MAC
verification.</a> This is still a weak combination and if I lived near
a wireless "hot spot", I would probably add IPSEC or something similar
to my WiFi-&gt;local connections.<br>
</p>
<p> 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). The system also runs fetchmail to fetch our
email from our old and current ISPs. That server is managed through
Proxy ARP.</p>
<p> The firewall system itself runs a DHCP server that serves the
local network.</p>
<p> All administration and publishing is done using ssh/scp. I have X
installed on the firewall but no X server or desktop is installed. X
applications tunnel through SSH to XWin.exe running on Ursa. The server
does have 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 RedHat).</p>
<p> I run an SNMP server on my firewall to serve <a
href="http://www.ee.ethz.ch/%7Eoetiker/webtools/mrtg/"> MRTG</a>
running in the DMZ.</p>
<p align="center"> <img border="0" src="images/network.png"
width="764" height="846" alt="(My network layout)"> </p>
<p>&nbsp;</p>
<p>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, my /sbin/ifup-local
script (see below)
adds a host route to 206.124.146.177 through eth1 when that interface
is brought up.</p>
<p>Ursa (192.168.1.5 A.K.A. 206.124.146.178) runs a PPTP server for
Road
Warrior access.<br>
</p>
<p><font color="#ff0000" size="5"></font></p>
</blockquote>
<h3>Shorewall.conf</h3>
<blockquote>
<pre>LOGFILE=/var/log/messages<br>LOGRATE=<br>LOGBURST=<br>LOGUNCLEAN=$LOG<br>BLACKLIST_LOGLEVEL=<br>LOGNEWNOTSYN=<br>MACLIST_LOG_LEVEL=$LOG<br>TCP_FLAGS_LOG_LEVEL=$LOG<br>RFC1918_LOG_LEVEL=$LOG<br>PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:/usr/local/sbin<br>SHOREWALL_SHELL=/bin/ash<br>SUBSYSLOCK=/var/lock/subsys/shorewall<br>STATEDIR=/var/state/shorewall<br>MODULESDIR=<br>FW=fw<br>IP_FORWARDING=On<br>ADD_IP_ALIASES=Yes<br>ADD_SNAT_ALIASES=Yes<br>TC_ENABLED=Yes<br>CLEAR_TC=No<br>MARK_IN_FORWARD_CHAIN=No<br>CLAMPMSS=Yes<br>ROUTE_FILTER=No<br>NAT_BEFORE_RULES=No<br>DETECT_DNAT_IPADDRS=Yes<br>MUTEX_TIMEOUT=60<br>NEWNOTSYN=No<br>BLACKLIST_DISPOSITION=DROP<br>MACLIST_DISPOSITION=REJECT<br>TCP_FLAGS_DISPOSITION=DROP<br>SHARED_DIR=/usr/share/shorewall<br></pre>
</blockquote>
<h3>Params File (Edited):</h3>
<blockquote>
<pre>MIRRORS=<i>&lt;list of shorewall mirror ip addresses&gt;</i><br>NTPSERVERS=<i>&lt;list of the NTP servers I sync with&gt;</i>
TEXAS=<i>&lt;ip address of gateway in Dallas&gt;</i><br>LOG=info<br></pre>
</blockquote>
<h3>Zones File</h3>
<blockquote>
<pre>#ZONE DISPLAY COMMENTS<br>net Internet Internet<br>WiFi Wireless Wireless Network on eth3<br>me Wookie My Linux Workstation<br>dmz DMZ Demilitarized zone<br>loc Local Local networks<br>tx Texas Peer Network in Dallas<br>#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE<font
face="Courier" size="2"><br></font></pre>
</blockquote>
<h3>Interfaces File: </h3>
<blockquote>
<p> This is set up so that I can start the firewall before bringing
up
my Ethernet interfaces. </p>
</blockquote>
<blockquote>
<pre>#ZONE INERFACE BROADCAST OPTIONS<br>net eth0 206.124.146.255 dhcp,norfc1918,routefilter,blacklist,tcpflags<br>loc eth2 192.168.1.255 dhcp,newnotsyn<br>dmz eth1 192.168.2.255 newnotsyn<br>WiFi eth3 192.168.3.255 dhcp,maclist,newnotsyn<br>- texas 192.168.9.255<br>#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE<font
face="Courier" size="2"><br></font> </pre>
</blockquote>
<h3>Hosts File: </h3>
<blockquote>
<pre>#ZONE HOST(S) OPTIONS<br>me&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; eth2:192.168.1.3<br>tx&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; texas:192.168.8.0/22<br>#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE</pre>
</blockquote>
<h3>Routestopped File:</h3>
<blockquote>
<pre>#INTERFACQ HOST(S)<br>eth1 206.124.146.177<br>eth2 -<br>eth3 192.168.3.0/24<br>#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE<font
face="Courier" size="2"> </font></pre>
</blockquote>
<h3>Policy File:</h3>
<blockquote>
<pre>#SOURCE DESTINATION POLICY LOG LEVEL BURST:LIMIT<br>me loc NONE # 'me' and 'loc' are in the same network<br>me all ACCEPT # Allow my workstation unlimited access<br>tx me ACCEPT # Alow Texas access to my workstation<br>WiFi loc ACCEPT # Allow the wireless new access<br>all me CONTINUE # Use all-&gt;loc rules for my WS also<br>loc net ACCEPT # Allow all net traffic from local net<br>$FW loc ACCEPT # Allow local access from the firewall<br>$FW tx ACCEPT # Allow firewall access to texas<br>loc tx ACCEPT # Allow local net access to texas<br>loc fw REJECT $LOG # Reject loc-&gt;fw and log<br>WiFi net ACCEPT # Allow internet access from wirless<br>net all DROP $LOG 10/sec:40 # Rate limit and<br> # DROP net-&gt;dmz<br>all all REJECT $LOG # Reject and log the rest<br>#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE<br></pre>
</blockquote>
<h3>Masq File: </h3>
<blockquote>
<p> 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 my
personal system (192.168.1.3), our laptop (192.168.3.8) and
visitors with laptops.<br>
</p>
</blockquote>
<blockquote>
<pre>#INTERFACE SUBNET ADDRESS<br>eth0 eth2 206.124.146.179<br>eth0 eth3 206.124.146.179<br>#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS LINE -- DO NOT REMOVE<br></pre>
</blockquote>
<h3>NAT File: </h3>
<blockquote>
<pre>#EXTERNAL INTERFACE INTERNAL ALL INTERFACES LOCAL<br>206.124.146.178 eth0:0 192.168.1.5 No No<br>206.124.146.180 eth0:2 192.168.1.7 No No<br>#<br># The following entry allows the server to be accessed through an address in<br># the local network. This is convenient when I'm on the road and connected<br># to the PPTP server. By doing this, I don't need to set my client's default<br># gateway to route through the tunnel.<br>#<br>192.168.1.193 eth2:0 206.124.146.177 No No<br>#LAST LINE -- ADD YOUR ENTRIES ABOVE THIS LINE -- DO NOT REMOVE\</pre>
</blockquote>
<h3>Proxy ARP File:</h3>
<blockquote>
<pre>#ADDRESS INTERFACE EXTERNAL HAVEROUTE<br>206.124.146.177 eth1 eth0 Yes<br>#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE<font
face="Courier" size="2"> </font></pre>
</blockquote>
<h3>Tunnels File (Shell variable TEXAS set in /etc/shorewall/params):</h3>
<blockquote>
<pre>#TYPE ZONE GATEWAY GATEWAY ZONE PORT<br>gre net $TEXAS<br>#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE<br></pre>
</blockquote>
<h3></h3>
<h3>Actions File</h3>
<pre style="margin-left: 40px;">#ACTION<br>Mirrors #Action that accepts traffic from our mirrors<br>#LAST LINE - ADD YOUR ENTRIES ABOVE THIS ONE - DO NOT REMOVE<br></pre>
<h3>/etc/shorewall/action.Mirrors<br>
</h3>
<pre style="margin-left: 40px;">#TARGET SOURCE DEST PROTO DEST SOURCE ORIGINAL RATE<br># PORT PORT(S) DEST LIMIT<br>ACCEPT $MIRRORS <br>#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE<br></pre>
<h3>Rules File (The shell variables are set in /etc/shorewall/params):</h3>
<blockquote>
<pre>################################################################################################################################################################<br>#RESULT CLIENT(S) SERVER(S) PROTO PORT(S) CLIENT ORIGINAL DEST:SNAT<br>################################################################################################################################################################<br># Local Network to Internet - Reject attempts by Trojans to call home<br>#<br>REJECT:$LOG loc net tcp 6667<br>#<br># Stop NETBIOS crap since our policy is ACCEPT<br>#<br>REJECT loc net tcp 137,445<br>REJECT loc net udp 137:139<br>################################################################################################################################################################<br># Local Network to Firewall<br>#<br>DROP loc:!192.168.1.0/24 fw<br>ACCEPT loc fw tcp ssh,time,10000,swat,137,139,445<br>ACCEPT loc fw udp snmp,ntp,445<br>ACCEPT loc fw udp 137:139<br>ACCEPT loc fw udp 1024: 137<br>################################################################################################################################################################<br># Local Network to DMZ<br>#<br>ACCEPT loc dmz udp domain,xdmcp<br>ACCEPT loc dmz tcp www,smtp,domain,ssh,imap,https,imaps,cvspserver,ftp,10000,8080,pop3 -<br>################################################################################################################################################################<br># Me to DMZ (This compensates for the broken RH kernel running in the DMZ -- that kernel's REJECT target is broken and Evolution requires a REJECT from smtps).<br>#<br>REJECT me dmz tcp 465<br>################################################################################################################################################################<br># Internet to DMZ<br>#<br>ACCEPT net dmz tcp smtp,www,ftp,imaps,domain,cvspserver,https -<br>ACCEPT net dmz udp domain<br>Mirrors net dmz tcp rsync<br>ACCEPT:$LOG net dmz tcp 32768:61000 20<br>DROP net dmz tcp 1433<br>################################################################################################################################################################<br>#<br># Net to Local<br>#<br># When I'm "on the road", the following two rules allow me VPN access back home.<br>#<br>ACCEPT net loc:192.168.1.5 tcp 1723<br>ACCEPT net loc:192.168.1.5 gre<br>#<br># ICQ<br>#<br>ACCEPT net loc:192.168.1.5 tcp 4000:4100<br>#<br># Real Audio<br>#<br>ACCEPT net loc:192.168.1.5 udp 6970:7170<br>DNAT net loc:192.168.1.3 udp 6970:7170 - 206.124.146.179<br>################################################################################################################################################################<br># Net to me<br>#<br>ACCEPT net loc:192.168
</blockquote>
The next three files deal with redirecting html requests to Squid on
the DMZ server.<span style="font-weight: bold;"><br>
</span>
<h3><span style="font-weight: bold;">Tcrules file:<br>
</span></h3>
<pre style="margin-left: 40px;">#MARK SOURCE DEST PROTO PORT(S) CLIENT PORT(S)<br>#<br># In the PREROUTING chain, mark all HTML connection requests to external <br># servers with value 1<br>#<br>1:P eth2 !192.168.0.0/16 tcp 80<br>#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE<br></pre>
<h3><span style="font-weight: bold;">Init file:<br>
</span></h3>
<pre style="margin-left: 40px;">#<br># Add a second routing table with my server as the default gateway<br># Use this routing table with all packets marked with value 1<br># <br>if [ -z "`ip route list table 202 2&gt; /dev/null`" ] ; then<br> run_ip rule add fwmark 1 table www.out<br> run_ip route add default via 206.124.146.177 dev eth1 table www.out<br> run_ip route flush cache<br>fi<br></pre>
<h3><span style="font-weight: bold;">/etc/iproute2/rt_tables:</span></h3>
<pre style="margin-left: 40px;">#<br># reserved values<br>#<br>#255 local<br>#254 main<br>#253 default<br>#0 unspec<br> <br>#<br># local -- I added the entry below<br>#<br>202 www.out<br></pre>
<span style="font-weight: bold;"></span>
<h3><span style="font-weight: bold;">Tcstart file:<br>
</span></h3>
<span style="font-weight: bold;"><br>
</span>
<div style="margin-left: 40px;">My tcstart file is just the HTB version
of WonderShaper.<br>
</div>
<br>
<h3>Newnotsyn file (/etc/shorewall/newnotsyn):</h3>
<div style="margin-left: 40px;">I prefer to allow SYN, FIN and RST
packets unconditionally rather than just on 'newnotsyn' interfaces as
is the case with the standard Shorewall ruleset. This file deletes the
Shorewall-generated rules for these packets and creates my own.<br>
<pre>#!/bin/sh<br> <br>for interface in `find_interfaces_by_option newnotsyn`; do<br> run_iptables -D newnotsyn -i $interface -p tcp --tcp-flags ACK ACK -j ACCEPT<br> run_iptables -D newnotsyn -i $interface -p tcp --tcp-flags RST RST -j ACCEPT<br> run_iptables -D newnotsyn -i $interface -p tcp --tcp-flags FIN FIN -j ACCEPT<br>done<br> <br>run_iptables -A newnotsyn -p tcp --tcp-flags ACK ACK -j ACCEPT<br>run_iptables -A newnotsyn -p tcp --tcp-flags RST RST -j ACCEPT<br>run_iptables -A newnotsyn -p tcp --tcp-flags FIN FIN -j ACCEPT<br></pre>
</div>
<h3><span style="font-weight: bold;">/sbin/ifup-local</span></h3>
<div style="margin-left: 40px;"><span style="font-weight: bold;"></span>This
file is Redhat specific and adds a route to my DMZ server when eth1 is
brought up.<br>
It allows me to enter "Yes" in the HAVEROUTE column of my Proxy ARP
file.<br>
</div>
<pre style="margin-left: 40px;">#!/bin/sh<br><br>case $1 in<br> eth1)<br> ip route add 206.124.146.177 dev eth1<br> ;;<br>esac<br></pre>
<pre style="margin-left: 40px;"><span style="font-family: sans-serif;"></span></pre>
<p><font size="2">Last updated 12/06/2003 - <a href="support.htm">Tom
Eastep</a></font> </p>
<a href="copyright.htm"><font size="2">Copyright</font> <20> <font
size="2">2001, 2002, 2003 Thomas M. Eastep.</font></a><br>
<br>
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