mirror of
https://gitlab.com/shorewall/code.git
synced 2024-12-27 16:49:05 +01:00
9fd5780f36
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@1439 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
184 lines
7.0 KiB
XML
184 lines
7.0 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<article id="MAC_Validation">
|
|
<!--$Id$-->
|
|
|
|
<articleinfo>
|
|
<title>MAC Verification</title>
|
|
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Tom</firstname>
|
|
|
|
<surname>Eastep</surname>
|
|
</author>
|
|
</authorgroup>
|
|
|
|
<pubdate>2004-04-05</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>
|
|
|
|
<para>All traffic from an interface or from a subnet on an interface can be
|
|
verified to originate from a defined set of MAC addresses. Furthermore, each
|
|
MAC address may be optionally associated with one or more IP addresses.</para>
|
|
|
|
<important>
|
|
<para><emphasis role="bold">MAC addresses are only visible within an
|
|
ethernet segment so all MAC addresses used in verification must belong to
|
|
devices physically connected to one of the LANs to which your firewall is
|
|
connected.</emphasis></para>
|
|
</important>
|
|
|
|
<important>
|
|
<para><emphasis role="bold">Your kernel must include MAC match support
|
|
(CONFIG_IP_NF_MATCH_MAC - module name ipt_mac.o).</emphasis></para>
|
|
</important>
|
|
|
|
<section>
|
|
<title>Components</title>
|
|
|
|
<para>There are four components to this facility.</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>The <emphasis role="bold">maclist</emphasis> interface option in
|
|
<ulink url="Documentation.htm#Interfaces">/etc/shorewall/interfaces</ulink>.
|
|
When this option is specified, all traffic arriving on the interface
|
|
is subjet to MAC verification.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The <emphasis role="bold">maclist</emphasis> option in <ulink
|
|
url="Documentation.htm#Hosts">/etc/shorewall/hosts</ulink>. When this
|
|
option is specified for a subnet, all traffic from that subnet is
|
|
subject to MAC verification.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The /etc/shorewall/maclist file. This file is used to associate
|
|
MAC addresses with interfaces and to optionally associate IP addresses
|
|
with MAC addresses.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The <emphasis role="bold">MACLIST_DISPOSITION</emphasis> and
|
|
<emphasis role="bold">MACLIST_LOG_LEVEL</emphasis> variables in <ulink
|
|
url="Documentation.htm#Conf">/etc/shorewall/shorewall.conf</ulink>.
|
|
The MACLIST_DISPOSITION variable has the value DROP, REJECT or ACCEPT
|
|
and determines the disposition of connection requests that fail MAC
|
|
verification. The MACLIST_LOG_LEVEL variable gives the syslogd level
|
|
at which connection requests that fail verification are to be logged.
|
|
If set the the empty value (e.g., MACLIST_LOG_LEVEL="") then
|
|
failing connection requests are not logged.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
</section>
|
|
|
|
<section>
|
|
<title>/etc/shorewall/maclist</title>
|
|
|
|
<para>The columns in /etc/shorewall/maclist are:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>INTERFACE</term>
|
|
|
|
<listitem>
|
|
<para>The name of an ethernet interface on the Shorewall system.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>MAC</term>
|
|
|
|
<listitem>
|
|
<para>The MAC address of a device on the ethernet segment connected
|
|
by INTERFACE. It is not necessary to use the Shorewall MAC format in
|
|
this column although you may use that format if you so choose.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>IP Address</term>
|
|
|
|
<listitem>
|
|
<para>An optional comma-separated list of IP addresses for the
|
|
device whose MAC is listed in the MAC column.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</section>
|
|
|
|
<section>
|
|
<title>Examples</title>
|
|
|
|
<example>
|
|
<title>Here are my files (look <ulink url="myfiles.htm">here</ulink> for
|
|
details about my setup)</title>
|
|
|
|
<para>/etc/shorewall/shorewall.conf:</para>
|
|
|
|
<programlisting>MACLIST_DISPOSITION=REJECT
|
|
MACLIST_LOG_LEVEL=info</programlisting>
|
|
|
|
<para>/etc/shorewall/interfaces:</para>
|
|
|
|
<programlisting>#ZONE INTERFACE BROADCAST OPTIONS
|
|
net eth0 206.124.146.255 dhcp,norfc1918,routefilter,blacklist,tcpflags
|
|
loc eth2 192.168.1.255 dhcp
|
|
dmz eth1 192.168.2.255
|
|
WiFi eth3 192.168.3.255 dhcp,maclist
|
|
- texas 192.168.9.255</programlisting>
|
|
|
|
<para>/etc/shorewall/maclist:</para>
|
|
|
|
<programlisting>#INTERFACE MAC IP ADDRESSES (Optional)
|
|
eth3 00:A0:CC:A2:0C:A0 192.168.3.7 #Work Laptop
|
|
eth3 00:04:5a:fe:85:b9 192.168.3.250 #WAP11
|
|
eth3 00:06:25:56:33:3c 192.168.3.225,192.168.3.8 #WET11
|
|
eth3 00:0b:cd:C4:cc:97 192.168.3.8 #TIPPER</programlisting>
|
|
|
|
<para>As shown above, I use MAC Verification on my wireless zone.</para>
|
|
|
|
<para><note><para>While marketed as a wireless bridge, the WET11 behaves
|
|
like a wireless router with DHCP relay. When forwarding DHCP traffic, it
|
|
uses the MAC address of the host (TIPPER) but for other forwarded
|
|
traffic it uses it's own MAC address. Consequently, I list the IP
|
|
addresses of both devices in /etc/shorewall/maclist.</para></note></para>
|
|
</example>
|
|
|
|
<example>
|
|
<title>Router in Wireless Zone</title>
|
|
|
|
<para>Suppose now that I add a second wireless segment to my wireless
|
|
zone and gateway that segment via a router with MAC address
|
|
00:06:43:45:C6:15 and IP address 192.168.3.253. Hosts in the second
|
|
segment have IP addresses in the subnet 192.168.4.0/24. I would add the
|
|
following entry to my /etc/shorewall/maclist file:</para>
|
|
|
|
<programlisting>eth3 00:06:43:45:C6:15 192.168.3.253,192.168.4.0/24</programlisting>
|
|
|
|
<para>This entry accomodates traffic from the router itself
|
|
(192.168.3.253) and from the second wireless segment (192.168.4.0/24).
|
|
Remember that all traffic being sent to my firewall from the
|
|
192.168.4.0/24 segment will be forwarded by the router so that
|
|
traffic's MAC address will be that of the router (00:06:43:45:C6:15)
|
|
and not that of the host sending the traffic.</para>
|
|
</example>
|
|
</section>
|
|
</article> |