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Update the blacklisting article for 5.0

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Signed-off-by: Tom Eastep <teastep@shorewall.net>
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Tom Eastep 2016-02-17 15:48:10 -08:00
parent 6599425ce9
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1 changed files with 60 additions and 230 deletions
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docs/blacklisting_support.xml
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@ -85,14 +85,13 @@
url="manpages/shorewall-blrules.html">shorewall-blrules</ulink> (5)).
There you have access to the DROP, ACCEPT, REJECT and WHITELIST actions,
standard and custom macros as well as standard and custom actions. See
<ulink url="manpages/shorewall-rules.html">shorewall-rules</ulink> (5) for
details.</para>
<ulink url="manpages/shorewall-rules.html">shorewall-blrules</ulink> (5)
for details.</para>
<para>Example:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST
# PORTS(S)
SECTION BLACKLIST
<programlisting>#ACTION SOURCE DEST PROTO DPORT
WHITELIST net:70.90.191.126 all
DROP net all udp 1023:1033,1434,5948,23773
DROP all net udp 1023:1033
@ -107,147 +106,9 @@ DROP net:200.55.14.18 all
<para>Beginning with Shorewall 4.4.26, the <command>update</command>
command supports a <option>-b</option> option that causes your legacy
blacklisting configuration to use the blrules file.</para>
<note>
<para>If you prefer to keep your blacklisting rules in your rules file
(<ulink url="manpages/shorewall-rules.html">shorewall-rules</ulink>
(5)), you can place them in the BLACKLIST section of that file rather
than in blrules.</para>
</note>
</section>
<section>
<title>Legacy Blacklisting</title>
<para>Prior to 4.4.25, two forms of blacklisting were supported; static
and dynamic. The dynamic variety is still appropriate for
<firstterm>on-the-fly</firstterm> blacklisting; the static form is
deprecated.</para>
<important>
<para><emphasis role="bold">By default, only the source address is
checked against the blacklists</emphasis>. Blacklists only stop
blacklisted hosts from connecting to you — they do not stop you or your
users from connecting to blacklisted hosts .</para>
<variablelist>
<varlistentry>
<term>UPDATE</term>
<listitem>
<para>Beginning with Shorewall 4.4.12, you can also blacklist by
destination address. See <ulink
url="manpages/shorewall-blacklist.html">shorewall-blacklist</ulink>
(5) and <ulink url="manpages/shorewall.html">shorewall</ulink> (8)
for details.</para>
</listitem>
</varlistentry>
</variablelist>
</important>
<important>
<para><emphasis role="bold">Dynamic Shorewall blacklisting is not
appropriate for blacklisting 1,000s of different addresses. Static
Blacklisting can handle large blacklists but only if you use
ipsets</emphasis>. Without ipsets, the blacklists will take forever to
load, and will have a very negative effect on firewall
performance.</para>
</important>
<section id="Static">
<title>Static Blacklisting</title>
<para>Shorewall static blacklisting support has the following
configuration parameters:</para>
<itemizedlist>
<listitem>
<para>You specify whether you want packets from blacklisted hosts
dropped or rejected using the BLACKLIST_DISPOSITION setting in
<ulink
url="manpages/shorewall.conf.html"><filename>shorewall.conf</filename>(5).</ulink></para>
</listitem>
<listitem>
<para>You specify whether you want packets from blacklisted hosts
logged and at what syslog level using the BLACKLIST_LOGLEVEL setting
in <ulink
url="manpages/shorewall.conf.html"><filename>shorewall.conf</filename></ulink>(5).</para>
</listitem>
<listitem>
<para>You list the IP addresses/subnets that you wish to blacklist
in <ulink
url="manpages/shorewall-blacklist.html"><filename>shorewall-blacklist</filename></ulink>
(5). You may also specify PROTOCOL and Port numbers/Service names in
the blacklist file.</para>
</listitem>
<listitem>
<para>You specify the interfaces whose incoming packets you want
checked against the blacklist using the <quote>blacklist</quote>
option in <ulink
url="manpages/shorewall-interfaces.html"><filename>shorewall-interfaces</filename></ulink>(5)
(<ulink
url="manpages/shorewall-zones.html">shorewall-zones</ulink>(5) in
Shorewall 4.4.12 and later).</para>
</listitem>
</itemizedlist>
<para>Prior to Shorewall 4.4.20, only source-address static blacklisting
was supported.</para>
<para>Users with a large static black list may want to set the
DELAYBLACKLISTLOAD option in shorewall.conf (added in Shorewall version
2.2.0). When DELAYBLACKLISTLOAD=Yes, Shorewall will enable new
connections before loading the blacklist rules. While this may allow
connections from blacklisted hosts to slip by during construction of the
blacklist, it can substantially reduce the time that all new connections
are disabled during "shorewall [re]start".</para>
<para>Beginning with Shorewall 2.4.0, you can use <ulink
url="ipsets.html">ipsets</ulink> to define your static blacklist. Here's
an example:</para>
<programlisting>#ADDRESS/SUBNET PROTOCOL PORT
+Blacklistports[dst]
+Blacklistnets[src,dst]
+Blacklist[src,dst]
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE</programlisting>
<para>In this example, there is a portmap ipset
<emphasis>Blacklistports</emphasis> that blacklists all traffic with
destination ports included in the ipset. There are also
<emphasis>Blacklistnets</emphasis> (type <emphasis>nethash</emphasis>)
and <emphasis>Blacklist</emphasis> (type <emphasis>iphash</emphasis>)
ipsets that allow blacklisting networks and individual IP addresses.
Note that [src,dst] is specified so that individual entries in the sets
can be bound to other portmap ipsets to allow blacklisting
(<emphasis>source address</emphasis>, <emphasis>destination
port</emphasis>) combinations. For example:</para>
<programlisting>ipset -N SMTP portmap --from 1 --to 31
ipset -A SMTP 25
ipset -A Blacklist 206.124.146.177
ipset -B Blacklist 206.124.146.177 -b SMTP</programlisting>
<para>This will blacklist SMTP traffic from host 206.124.146.177.</para>
</section>
<section id="whitelisting">
<title>Static Whitelisting</title>
<para>Beginning with Shorewall 4.4.20, you can create
<firstterm>whitelist</firstterm> entries in the blacklist file.
Connections/packets matching a whitelist entry are not matched against
the entries in the blacklist file that follow. Whitelist entries are
created using the <emphasis role="bold">whitelist</emphasis> option
(OPTIONS column). See <ulink
url="manpages/shorewall-blacklist.html"><filename>shorewall-blacklist</filename></ulink>
(5).</para>
</section>
<section id="Dynamic">
<title>Dynamic Blacklisting</title>
<para>Beginning with Shorewall 4.4.7, dynamic blacklisting is enabled by
@ -255,8 +116,8 @@ ipset -B Blacklist 206.124.146.177 -b SMTP</programlisting>
Prior to that release, the feature is always enabled.</para>
<para>Once enabled, dynamic blacklisting doesn't use any configuration
parameters but is rather controlled using /sbin/shorewall[-lite]
commands. <emphasis role="bold">Note</emphasis> that <emphasis
parameters but is rather controlled using /sbin/shorewall[-lite] commands.
<emphasis role="bold">Note</emphasis> that <emphasis
role="bold">to</emphasis> and <emphasis role="bold">from</emphasis> may
only be specified when running <emphasis role="bold">Shorewall 4.4.12 or
later</emphasis>.</para>
@ -264,8 +125,8 @@ ipset -B Blacklist 206.124.146.177 -b SMTP</programlisting>
<itemizedlist>
<listitem>
<para>drop [to|from] <emphasis>&lt;ip address list&gt;</emphasis> -
causes packets from the listed IP addresses to be silently dropped
by the firewall.</para>
causes packets from the listed IP addresses to be silently dropped by
the firewall.</para>
</listitem>
<listitem>
@ -287,9 +148,10 @@ ipset -B Blacklist 206.124.146.177 -b SMTP</programlisting>
restarted.</para>
<para><emphasis role="bold">Update:</emphasis> Beginning with
Shorewall 4.4.10, the dynamic blacklist is automatically retained
over <command>stop/start</command> sequences and over
<command>restart</command>.</para>
Shorewall 4.4.10, the dynamic blacklist is automatically retained over
<command>stop/start</command> sequences and over
<command>restart</command> and <emphasis
role="bold">reload</emphasis>.</para>
</listitem>
<listitem>
@ -298,52 +160,20 @@ ipset -B Blacklist 206.124.146.177 -b SMTP</programlisting>
</listitem>
<listitem>
<para>logdrop [to|from] <emphasis>&lt;ip address list&gt;</emphasis>
- causes packets from the listed IP addresses to be dropped and
logged by the firewall. Logging will occur at the level specified by
the BLACKLIST_LOGLEVEL setting at the last [re]start (logging will
be at the 'info' level if no BLACKLIST_LOGLEVEL was given).</para>
<para>logdrop [to|from] <emphasis>&lt;ip address list&gt;</emphasis> -
causes packets from the listed IP addresses to be dropped and logged
by the firewall. Logging will occur at the level specified by the
BLACKLIST_LOGLEVEL setting at the last [re]start (logging will be at
the 'info' level if no BLACKLIST_LOGLEVEL was given).</para>
</listitem>
<listitem>
<para>logreject [to|from}<emphasis>&lt;ip address
list&gt;</emphasis> - causes packets from the listed IP addresses to
be rejected and logged by the firewall. Logging will occur at the
level specified by the BLACKLIST_LOGLEVEL setting at the last
[re]start (logging will be at the 'info' level if no
BLACKLIST_LOGLEVEL was given).</para>
<para>logreject [to|from}<emphasis>&lt;ip address list&gt;</emphasis>
- causes packets from the listed IP addresses to be rejected and
logged by the firewall. Logging will occur at the level specified by
the BLACKLIST_LOGLEVEL setting at the last [re]start (logging will be
at the 'info' level if no BLACKLIST_LOGLEVEL was given).</para>
</listitem>
</itemizedlist>
<para>Dynamic blacklisting is not dependent on the
<quote>blacklist</quote> option in
<filename>/etc/shorewall/interfaces</filename>.</para>
<example id="Ignore">
<title>Ignore packets from a pair of systems</title>
<programlisting> <command>shorewall[-lite] drop 192.0.2.124 192.0.2.125</command></programlisting>
<para>Drops packets from hosts 192.0.2.124 and 192.0.2.125</para>
</example>
<example id="Allow">
<title>Re-enable packets from a system</title>
<programlisting> <command>shorewall[-lite] allow 192.0.2.125</command></programlisting>
<para>Re-enables traffic from 192.0.2.125.</para>
</example>
<example>
<title>Displaying the Dynamic Blacklist</title>
<programlisting> <command>shorewall show dynamic</command></programlisting>
<para>Displays the 'dynamic' chain which contains rules for the
dynamic blacklist. The <firstterm>source</firstterm> column contains
the set of blacklisted addresses.</para>
</example>
</section>
</section>
</article>