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shorewall_code/manpages/shorewall-rules.xml
Tom Eastep 4e0225a4c3 Update Documentation for per-IP rate limiting fixes. 
Signed-off-by: Tom Eastep <teastep@shorewall.net>
2010-02-18 07:12:36 -08:00

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
<refentry>
<refmeta>
<refentrytitle>shorewall-rules</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>rules</refname>
<refpurpose>Shorewall rules file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>/etc/shorewall/rules</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>Entries in this file govern connection establishment by defining
exceptions to the policies layed out in <ulink
url="shorewall-policy.html">shorewall-policy</ulink>(5). By default,
subsequent requests and responses are automatically allowed using
connection tracking. For any particular (source,dest) pair of zones, the
rules are evaluated in the order in which they appear in this file and the
first terminating match is the one that determines the disposition of the
request. All rules are terminating except LOG and COUNT rules.</para>
<warning>
<para>If you masquerade or use SNAT from a local system to the internet,
you cannot use an ACCEPT rule to allow traffic from the internet to that
system. You <emphasis role="bold">must</emphasis> use a DNAT rule
instead.</para>
</warning>
<para>The rules file is divided into sections. Each section is introduced
by a "Section Header" which is a line beginning with SECTION and followed
by the section name.</para>
<para>Sections are as follows and must appear in the order listed:</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">ESTABLISHED</emphasis></term>
<listitem>
<para>Packets in the ESTABLISHED state are processed by rules in
this section.</para>
<para>The only ACTIONs allowed in this section are ACCEPT, DROP,
REJECT, LOG and QUEUE</para>
<para>There is an implicit ACCEPT rule inserted at the end of this
section.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">RELATED</emphasis></term>
<listitem>
<para>Packets in the RELATED state are processed by rules in this
section.</para>
<para>The only ACTIONs allowed in this section are ACCEPT, DROP,
REJECT, LOG and QUEUE</para>
<para>There is an implicit ACCEPT rule inserted at the end of this
section.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">NEW</emphasis></term>
<listitem>
<para>Packets in the NEW, INVALID and UNTRACKED states are processed
by rules in this section.</para>
</listitem>
</varlistentry>
</variablelist>
<note>
<para>If you are not familiar with Netfilter to the point where you are
comfortable with the differences between the various connection tracking
states, then it is suggested that you omit the <emphasis
role="bold">ESTABLISHED</emphasis> and <emphasis
role="bold">RELATED</emphasis> sections and place all of your rules in
the NEW section (That's after the line that reads SECTION NEW').</para>
</note>
<warning>
<para>If you specify FASTACCEPT=Yes in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5) then the <emphasis
role="bold">ESTABLISHED</emphasis> and <emphasis
role="bold">RELATED</emphasis> sections must be empty.</para>
</warning>
<para>You may omit any section that you don't need. If no Section Headers
appear in the file then all rules are assumed to be in the NEW
section.</para>
<para>When defining rules that rewrite the destination IP address and/or
port number (namely DNAT and REDIRECT rules), it is important to keep
straight which columns in the file specify the packet before rewriting and
which specify how the packet will look after rewriting.</para>
<itemizedlist>
<listitem>
<para>The DEST column specifies the final destination for the packet
after rewriting and can include the final IP address and/or port
number.</para>
</listitem>
<listitem>
<para>The remaining columns specify characteristics of the packet
before rewriting. In particular, the ORIGINAL DEST column gives the
original destination IP address of the packet and the DEST PORT(S)
column give the original destination port(s).</para>
</listitem>
</itemizedlist>
<para>The columns in the file are as follows.</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">ACTION</emphasis> - {<emphasis
role="bold">ACCEPT</emphasis>[<emphasis
role="bold"><option>+</option>|<option>!</option></emphasis>]|<emphasis
role="bold">NONAT</emphasis>|<emphasis
role="bold">DROP[<option>!</option>]</emphasis>|<emphasis
role="bold">REJECT</emphasis>[<option>!</option>]|<emphasis
role="bold">DNAT</emphasis>[<emphasis
role="bold">-</emphasis>]|<emphasis
role="bold">REDIRECT</emphasis>[<emphasis
role="bold">-</emphasis>]|<emphasis
role="bold">CONTINUE</emphasis>[<option>!</option>]|<emphasis
role="bold">LOG</emphasis>|<emphasis
role="bold">QUEUE</emphasis>[<option>!</option>]|<emphasis
role="bold">NFQUEUE[!]</emphasis>|COUNT[<emphasis
role="bold">(</emphasis><emphasis>queuenumber</emphasis><emphasis
role="bold">)</emphasis>]<emphasis
role="bold">|COMMENT</emphasis>|<emphasis>action</emphasis>|<emphasis>macro</emphasis>[<emphasis
role="bold">(</emphasis><emphasis>target</emphasis><emphasis
role="bold">)</emphasis>]}<emphasis
role="bold">[:</emphasis>{<emphasis>log-level</emphasis>|<emphasis
role="bold">none</emphasis>}[<emphasis role="bold"><emphasis
role="bold">!</emphasis></emphasis>][<emphasis
role="bold">:</emphasis><emphasis>tag</emphasis>]]</term>
<listitem>
<para>Specifies the action to be taken if the connection request
matches the rule. Must be one of the following.</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">ACCEPT</emphasis></term>
<listitem>
<para>Allow the connection request.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ACCEPT+</emphasis></term>
<listitem>
<para>like ACCEPT but also excludes the connection from any
subsequent matching <emphasis
role="bold">DNAT</emphasis>[<emphasis
role="bold">-</emphasis>] or <emphasis
role="bold">REDIRECT</emphasis>[<emphasis
role="bold">-</emphasis>] rules</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ACCEPT!</emphasis></term>
<listitem>
<para>like ACCEPT but exempts the rule from being suppressed
by OPTIMIZE=1 in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">NONAT</emphasis></term>
<listitem>
<para>Excludes the connection from any subsequent <emphasis
role="bold">DNAT</emphasis>[-] or <emphasis
role="bold">REDIRECT</emphasis>[-] rules but doesn't generate
a rule to accept the traffic.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DROP</emphasis></term>
<listitem>
<para>Ignore the request.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DROP!</emphasis></term>
<listitem>
<para>like DROP but exempts the rule from being suppressed by
OPTIMIZE=1 in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">REJECT</emphasis></term>
<listitem>
<para>disallow the request and return an icmp-unreachable or
an RST packet.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">REJECT!</emphasis></term>
<listitem>
<para>like REJECT but exempts the rule from being suppressed
by OPTIMIZE=1 in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DNAT</emphasis></term>
<listitem>
<para>Forward the request to another system (and optionally
another port).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DNAT-</emphasis></term>
<listitem>
<para>Advanced users only.</para>
<para>Like <emphasis role="bold">DNAT</emphasis> but only
generates the <emphasis role="bold">DNAT</emphasis> iptables
rule and not the companion <emphasis
role="bold">ACCEPT</emphasis> rule.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">REDIRECT</emphasis></term>
<listitem>
<para>Redirect the request to a server running on the
firewall.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">REDIRECT-</emphasis></term>
<listitem>
<para>Advanced users only.</para>
<para>Like <emphasis role="bold">REDIRECT</emphasis> but only
generates the <emphasis role="bold">REDIRECT</emphasis>
iptables rule and not the companion <emphasis
role="bold">ACCEPT</emphasis> rule.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">CONTINUE</emphasis></term>
<listitem>
<para>For experts only.</para>
<para>Do not process any of the following rules for this
(source zone,destination zone). If the source and/or
destination IP address falls into a zone defined later in
<ulink url="shorewall-zones.html">shorewall-zones</ulink>(5)
or in a parent zone of the source or destination zones, then
this connection request will be passed to the rules defined
for that (those) zone(s). See <ulink
url="shorewall-nesting.html">shorewall-nesting</ulink>(5) for
additional information.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">CONTINUE!</emphasis></term>
<listitem>
<para>like CONTINUE but exempts the rule from being suppressed
by OPTIMIZE=1 in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">LOG</emphasis></term>
<listitem>
<para>Simply log the packet and continue with the next
rule.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">QUEUE</emphasis></term>
<listitem>
<para>Queue the packet to a user-space application such as
ftwall (http://p2pwall.sf.net). The application may reinsert
the packet for further processing.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">QUEUE!</emphasis></term>
<listitem>
<para>like QUEUE but exempts the rule from being suppressed by
OPTIMIZE=1 in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>NFQUEUE</term>
<listitem>
<para>Queues the packet to a user-space application using the
nfnetlink_queue mechanism. If a
<replaceable>queuenumber</replaceable> is not specified, queue
zero (0) is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">NFQUEUE!</emphasis></term>
<listitem>
<para>like NFQUEUE but exempts the rule from being suppressed
by OPTIMIZE=1 in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>COUNT</term>
<listitem>
<para>Simply increment the rule's packet and byte count and
pass the packet to the next rule.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">COMMENT</emphasis></term>
<listitem>
<para>the rest of the line will be attached as a comment to
the Netfilter rule(s) generated by the following entries. The
comment will appear delimited by "/* ... */" in the output of
"shorewall show &lt;chain&gt;". To stop the comment from being
attached to further rules, simply include COMMENT on a line by
itself.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis>action</emphasis></term>
<listitem>
<para>The name of an <emphasis>action</emphasis> declared in
<ulink
url="shorewall-actions.html">shorewall-actions</ulink>(5) or
in /usr/share/shorewall/actions.std.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis>macro</emphasis></term>
<listitem>
<para>The name of a macro defined in a file named
macro.<emphasis>macro</emphasis>. If the macro accepts an
action parameter (Look at the macro source to see if it has
PARAM in the TARGET column) then the
<emphasis>macro</emphasis> name is followed by the
parenthesized <emphasis>target</emphasis> (<emphasis
role="bold">ACCEPT</emphasis>, <emphasis
role="bold">DROP</emphasis>, <emphasis
role="bold">REJECT</emphasis>, ...) to be substituted for the
parameter.</para>
<para>Example: FTP(ACCEPT).</para>
<para>The older syntax where the macro name and the target are
separated by a slash (e.g. FTP/ACCEPT) is still allowed but is
deprecated.</para>
<para>The <emphasis role="bold">ACTION</emphasis> may
optionally be followed by ":" and a syslog log level (e.g,
REJECT:info or DNAT:debug). This causes the packet to be
logged at the specified level. Note that if the <emphasis
role="bold">ACTION</emphasis> involves destination network
address translation (DNAT, REDIRECT, etc.) then the packet is
logged <emphasis role="bold">before</emphasis> the destination
address is rewritten.</para>
<para>If the <emphasis role="bold">ACTION</emphasis> names an
<emphasis>action</emphasis> declared in <ulink
url="shorewall-actions.html">shorewall-actions</ulink>(5) or
in /usr/share/shorewall/actions.std then:</para>
<itemizedlist>
<listitem>
<para>If the log level is followed by "!' then all rules
in the action are logged at the log level.</para>
</listitem>
<listitem>
<para>If the log level is not followed by "!" then only
those rules in the action that do not specify logging are
logged at the specified level.</para>
</listitem>
<listitem>
<para>The special log level <emphasis
role="bold">none!</emphasis> suppresses logging by the
action.</para>
</listitem>
</itemizedlist>
<para>You may also specify <emphasis
role="bold">ULOG</emphasis> or <emphasis
role="bold">NFLOG</emphasis> (must be in upper case) as a log
level.This will log to the ULOG or NFLOG target for routing to
a separate log through use of ulogd (<ulink
url="http://www.netfilter.org/projects/ulogd/index.html">http://www.netfilter.org/projects/ulogd/index.html</ulink>).</para>
<para>Actions specifying logging may be followed by a log tag
(a string of alphanumeric characters) which is appended to the
string generated by the LOGPREFIX (in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5)).</para>
<para>Example: ACCEPT:info:ftp would include 'ftp ' at the end
of the log prefix generated by the LOGPREFIX setting.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">SOURCE</emphasis> -
{<emphasis>zone</emphasis>|{<emphasis
role="bold">all</emphasis>|<emphasis
role="bold">any</emphasis>}[<emphasis
role="bold">+</emphasis>][<emphasis
role="bold">-</emphasis>]}<emphasis
role="bold">[:</emphasis><emphasis>interface</emphasis>][<emphasis
role="bold">:</emphasis>{<emphasis>address-or-range</emphasis>[,<emphasis>address-or-range</emphasis>]...[<emphasis>exclusion</emphasis>]|<emphasis>exclusion</emphasis>|<emphasis
role="bold">+</emphasis><emphasis>ipset</emphasis>}</term>
<listitem>
<para>Source hosts to which the rule applies. May be a zone declared
in /etc/shorewall/zones, <emphasis role="bold">$FW</emphasis> to
indicate the firewall itself, <emphasis role="bold">all</emphasis>,
<emphasis role="bold">all+</emphasis>, <emphasis
role="bold">all-</emphasis>, <emphasis role="bold">all+-</emphasis>
or <emphasis role="bold">none</emphasis>.</para>
<para>When <emphasis role="bold">none</emphasis> is used either in
the <emphasis role="bold">SOURCE</emphasis> or <emphasis
role="bold">DEST</emphasis> column, the rule is ignored.</para>
<para><emphasis role="bold">all</emphasis> means "All Zones",
including the firewall itself. <emphasis role="bold">all-</emphasis>
means "All Zones, except the firewall itself". When <emphasis
role="bold">all</emphasis>[<emphasis role="bold">-</emphasis>] is
used either in the <emphasis role="bold">SOURCE</emphasis> or
<emphasis role="bold">DEST</emphasis> column intra-zone traffic is
not affected. When <emphasis role="bold">all+</emphasis>[<emphasis
role="bold">-</emphasis>] is "used, intra-zone traffic is
affected.</para>
<para>Except when <emphasis role="bold">all</emphasis>[<emphasis
role="bold">+</emphasis>][<emphasis role="bold">-</emphasis>] is
specified, clients may be further restricted to a list of networks
and/or hosts by appending ":" and a comma-separated list of network
and/or host addresses. Hosts may be specified by IP or MAC address;
mac addresses must begin with "~" and must use "-" as a
separator.</para>
<para><emphasis role="bold">any</emphasis> is equivalent to
<emphasis role="bold">all</emphasis> when there are no nested zones.
When there are nested zones, <emphasis role="bold">any</emphasis>
only refers to top-level zones (those with no parent zones).</para>
<para>Hosts may also be specified as an IP address range using the
syntax
<emphasis>lowaddress</emphasis>-<emphasis>highaddress</emphasis>.
This requires that your kernel and iptables contain iprange match
support. If your kernel and iptables have ipset match support then
you may give the name of an ipset prefaced by "+". The ipset name
may be optionally followed by a number from 1 to 6 enclosed in
square brackets ([]) to indicate the number of levels of source
bindings to be matched.</para>
<para>You may exclude certain hosts from the set already defined
through use of an <emphasis>exclusion</emphasis> (see <ulink
url="shorewall-exclusion.html">shorewall-exclusion</ulink>(5)).</para>
<para>Examples:</para>
<variablelist>
<varlistentry>
<term>dmz:192.168.2.2</term>
<listitem>
<para>Host 192.168.2.2 in the DMZ</para>
</listitem>
</varlistentry>
<varlistentry>
<term>net:155.186.235.0/24</term>
<listitem>
<para>Subnet 155.186.235.0/24 on the Internet</para>
</listitem>
</varlistentry>
<varlistentry>
<term>loc:192.168.1.1,192.168.1.2</term>
<listitem>
<para>Hosts 192.168.1.1 and 192.168.1.2 in the local
zone.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>loc:~00-A0-C9-15-39-78</term>
<listitem>
<para>Host in the local zone with MAC address
00:A0:C9:15:39:78.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>net:192.0.2.11-192.0.2.17</term>
<listitem>
<para>Hosts 192.0.2.11-192.0.2.17 in the net zone.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>net:!192.0.2.11-192.0.2.17</term>
<listitem>
<para>All hosts in the net zone except for
192.0.2.11-192.0.2.17.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>net:155.186.235.0/24!155.186.235.16/28</term>
<listitem>
<para>Subnet 155.186.235.0/24 on the Internet except for
155.186.235.16/28</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DEST</emphasis> -
{<emphasis>zone</emphasis>|{<emphasis
role="bold">all</emphasis>|<emphasis
role="bold">any</emphasis>}[<emphasis
role="bold">+</emphasis>][<emphasis
role="bold">-</emphasis>]}<emphasis
role="bold">[:{</emphasis><emphasis>interface</emphasis>|<emphasis>address-or-range</emphasis>[,<emphasis>address-or-range</emphasis>]...[<emphasis>exclusion</emphasis>]|<emphasis>exclusion</emphasis>|<emphasis
role="bold">+</emphasis><emphasis>ipset</emphasis>}][<option>:</option><replaceable>port</replaceable>[:<emphasis
role="bold">random</emphasis>]]</term>
<listitem>
<para>Location of Server. May be a zone declared in <ulink
url="shorewall-zones.html">shorewall-zones</ulink>(5), $<emphasis
role="bold">FW</emphasis> to indicate the firewall itself, <emphasis
role="bold">all</emphasis>. <emphasis role="bold">all+</emphasis> or
<emphasis role="bold">none</emphasis>.</para>
<para>When <emphasis role="bold">none</emphasis> is used either in
the <emphasis role="bold">SOURCE</emphasis> or <emphasis
role="bold">DEST</emphasis> column, the rule is ignored.</para>
<para>When <emphasis role="bold">all</emphasis> is used either in
the <emphasis role="bold">SOURCE</emphasis> or <emphasis
role="bold">DEST</emphasis> column intra-zone traffic is not
affected. When <emphasis role="bold">all+</emphasis> is used,
intra-zone traffic is affected.</para>
<para><emphasis role="bold">any</emphasis> is equivalent to
<emphasis role="bold">all</emphasis> when there are no nested zones.
When there are nested zones, <emphasis role="bold">any</emphasis>
only refers to top-level zones (those with no parent zones).</para>
<para>The <replaceable>zone</replaceable> should be omitted in
DNAT-, REDIRECT- and NONAT rules.</para>
<para>If the DEST <replaceable>zone</replaceable> is a bport zone,
then either:<orderedlist numeration="loweralpha">
<listitem>
<para>the SOURCE must be <option>all[+][-]</option>, or</para>
</listitem>
<listitem>
<para>the SOURCE <replaceable>zone</replaceable> must be
another bport zone associated with the same bridge, or</para>
</listitem>
<listitem>
<para>the SOURCE <replaceable>zone</replaceable> must be an
ipv4 zone that is associated with only the same bridge.</para>
</listitem>
</orderedlist></para>
<blockquote>
<para></para>
<para>Except when <emphasis role="bold">all</emphasis>[<emphasis
role="bold">+]|[-</emphasis>] is specified, the server may be
further restricted to a particular network, host or interface by
appending ":" and the network, host or interface. See <emphasis
role="bold">SOURCE</emphasis> above.</para>
<para>You may exclude certain hosts from the set already defined
through use of an <emphasis>exclusion</emphasis> (see <ulink
url="shorewall-exclusion.html">shorewall-exclusion</ulink>(5)).</para>
<para>Restrictions:</para>
<para>1. MAC addresses are not allowed (this is a Netfilter
restriction).</para>
<para>2. You may not specify both an interface and an
address.</para>
<para>Like in the <emphasis role="bold">SOURCE</emphasis> column,
you may specify a range of IP addresses using the syntax
<emphasis>lowaddress</emphasis>-<emphasis>highaddress</emphasis>.
When the <emphasis role="bold">ACTION</emphasis> is <emphasis
role="bold">DNAT</emphasis> or <emphasis
role="bold">DNAT-</emphasis>, the connections will be assigned to
addresses in the range in a round-robin fashion.</para>
<para>If you kernel and iptables have ipset match support then you
may give the name of an ipset prefaced by "+". The ipset name may
be optionally followed by a number from 1 to 6 enclosed in square
brackets ([]) to indicate the number of levels of destination
bindings to be matched. Only one of the <emphasis
role="bold">SOURCE</emphasis> and <emphasis
role="bold">DEST</emphasis> columns may specify an ipset
name.</para>
<para>The <replaceable>port</replaceable> that the server is
listening on may be included and separated from the server's IP
address by ":". If omitted, the firewall will not modifiy the
destination port. A destination port may only be included if the
<emphasis role="bold">ACTION</emphasis> is <emphasis
role="bold">DNAT</emphasis> or <emphasis
role="bold">REDIRECT</emphasis>.</para>
<variablelist>
<varlistentry>
<term>Example:</term>
<listitem>
<para><emphasis role="bold">loc:192.168.1.3:3128</emphasis>
specifies a local server at IP address 192.168.1.3 and
listening on port 3128.</para>
</listitem>
</varlistentry>
</variablelist>
<para>The <emphasis>port</emphasis> may be specified as a service
name. You may specify a port range in the form
<emphasis>lowport-highport</emphasis> to cause connections to be
assigned to ports in the range in round-robin fashion. When a port
range is specified, <emphasis>lowport</emphasis> and
<emphasis>highport</emphasis> must be given as integers; service
names are not permitted. Additionally, the port range may be
optionally followed by <emphasis role="bold">:random</emphasis>
which causes assignment to ports in the list to be random.</para>
<para>If the <emphasis role="bold">ACTION</emphasis> is <emphasis
role="bold">REDIRECT</emphasis> or <emphasis
role="bold">REDIRECT-</emphasis>, this column needs only to
contain the port number on the firewall that the request should be
redirected to. That is equivalent to specifying
<option>$FW</option>::<replaceable>port</replaceable>.</para>
</blockquote>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">PROTO</emphasis> (Optional) - {<emphasis
role="bold">-</emphasis>|<emphasis
role="bold">tcp:syn</emphasis>|<emphasis
role="bold">ipp2p</emphasis>|<emphasis
role="bold">ipp2p:udp</emphasis>|<emphasis
role="bold">ipp2p:all</emphasis>|<emphasis>protocol-number</emphasis>|<emphasis>protocol-name</emphasis>|<emphasis
role="bold">all}</emphasis></term>
<listitem>
<para>Protocol - <emphasis role="bold">ipp2p</emphasis>* requires
ipp2p match support in your kernel and iptables. <emphasis
role="bold">tcp:syn</emphasis> implies <emphasis
role="bold">tcp</emphasis> plus the SYN flag must be set and the
RST,ACK and FIN flags must be reset.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DEST PORT(S) </emphasis>(Optional) -
{<emphasis
role="bold">-</emphasis>|<emphasis>port-name-number-or-range</emphasis>[<emphasis
role="bold">,</emphasis><emphasis>port-name-number-or-range</emphasis>]...}</term>
<listitem>
<para>Destination Ports. A comma-separated list of Port names (from
services(5)), port numbers or port ranges; if the protocol is
<emphasis role="bold">icmp</emphasis>, this column is interpreted as
the destination icmp-type(s). ICMP types may be specified as a
numeric type, a numberic type and code separated by a slash (e.g.,
3/4), or a typename. See <ulink
url="http://www.shorewall.net/configuration_file_basics.htm#ICMP">http://www.shorewall.net/configuration_file_basics.htm#ICMP</ulink>.</para>
<para>If the protocol is <emphasis role="bold">ipp2p</emphasis>,
this column is interpreted as an ipp2p option without the leading
"--" (example <emphasis role="bold">bit</emphasis> for bit-torrent).
If no port is given, <emphasis role="bold">ipp2p</emphasis> is
assumed.</para>
<para>A port range is expressed as
<emphasis>lowport</emphasis>:<emphasis>highport</emphasis>.</para>
<para>This column is ignored if <emphasis
role="bold">PROTO</emphasis> = <emphasis role="bold">all</emphasis>
but must be entered if any of the following columns are supplied. In
that case, it is suggested that this field contain a dash (<emphasis
role="bold">-</emphasis>).</para>
<para>If your kernel contains multi-port match support, then only a
single Netfilter rule will be generated if in this list and the
<emphasis role="bold">CLIENT PORT(S)</emphasis> list below:</para>
<para>1. There are 15 or less ports listed.</para>
<para>2. No port ranges are included or your kernel and iptables
contain extended multiport match support.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">SOURCE PORT(S)</emphasis> (Optional) -
{<emphasis
role="bold">-</emphasis>|<emphasis>port-name-number-or-range</emphasis>[<emphasis
role="bold">,</emphasis><emphasis>port-name-number-or-range</emphasis>]...}</term>
<listitem>
<para>Port(s) used by the client. If omitted, any source port is
acceptable. Specified as a comma- separated list of port names, port
numbers or port ranges.</para>
<warning>
<para>Unless you really understand IP, you should leave this
column empty or place a dash (<emphasis role="bold">-</emphasis>)
in the column. Most people who try to use this column get it
wrong.</para>
</warning>
<blockquote>
<para>If you don't want to restrict client ports but need to
specify an <emphasis role="bold">ORIGINAL DEST</emphasis> in the
next column, then place "-" in this column.</para>
<para>If your kernel contains multi-port match support, then only
a single Netfilter rule will be generated if in this list and the
<emphasis role="bold">DEST PORT(S)</emphasis> list above:</para>
<para>1. There are 15 or less ports listed.</para>
<para>2. No port ranges are included or your kernel and iptables
contain extended multiport match support.</para>
</blockquote>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ORIGINAL DEST</emphasis> (Optional) -
[<emphasis
role="bold">-</emphasis>|<emphasis>address</emphasis>[,<emphasis>address</emphasis>]...[<emphasis>exclusion</emphasis>]|<emphasis>exclusion</emphasis>]</term>
<listitem>
<para>If ACTION is <emphasis role="bold">DNAT</emphasis>[<emphasis
role="bold">-</emphasis>] or <emphasis
role="bold">REDIRECT</emphasis>[<emphasis role="bold">-</emphasis>]
then if this column is included and is different from the IP address
given in the <emphasis role="bold">DEST</emphasis> column, then
connections destined for that address will be forwarded to the IP
and port specified in the <emphasis role="bold">DEST</emphasis>
column.</para>
<para>A comma-separated list of addresses may also be used. This is
most useful with the <emphasis role="bold">REDIRECT</emphasis>
target where you want to redirect traffic destined for particular
set of hosts. Finally, if the list of addresses begins with "!"
(<emphasis>exclusion</emphasis>) then the rule will be followed only
if the original destination address in the connection request does
not match any of the addresses listed.</para>
<para>For other actions, this column may be included and may contain
one or more addresses (host or network) separated by commas. Address
ranges are not allowed. When this column is supplied, rules are
generated that require that the original destination address matches
one of the listed addresses. This feature is most useful when you
want to generate a filter rule that corresponds to a <emphasis
role="bold">DNAT-</emphasis> or <emphasis
role="bold">REDIRECT-</emphasis> rule. In this usage, the list of
addresses should not begin with "!".</para>
<para>It is also possible to specify a set of addresses then exclude
part of those addresses. For example, <emphasis
role="bold">192.168.1.0/24!192.168.1.16/28</emphasis> specifies the
addresses 192.168.1.0-182.168.1.15 and 192.168.1.32-192.168.1.255.
See <ulink
url="shorewall-exclusion.html">shorewall-exclusion</ulink>(5).</para>
<para>See <ulink
url="../PortKnocking.html">http://shorewall.net/PortKnocking.html</ulink>
for an example of using an entry in this column with a user-defined
action rule.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">RATE LIMIT</emphasis> (Optional) -
[<emphasis role="bold">-</emphasis>|[{<emphasis>s</emphasis>|<emphasis
role="bold">d</emphasis>}:[[<replaceable>name</replaceable>]:]]]<emphasis>rate</emphasis><emphasis
role="bold">/</emphasis>{<emphasis
role="bold">sec</emphasis>|<emphasis
role="bold">min</emphasis>}[:<emphasis>burst</emphasis>]</term>
<listitem>
<para>You may rate-limit the rule by placing a value in this
column:</para>
<para><emphasis>rate</emphasis> is the number of connections per
interval (<emphasis role="bold">sec</emphasis> or <emphasis
role="bold">min</emphasis>) and <emphasis>burst</emphasis> is the
largest burst permitted. If no <emphasis>burst</emphasis> is given,
a value of 5 is assumed. There may be no no whitespace embedded in
the specification.</para>
<para>Example: <emphasis role="bold">10/sec:20</emphasis></para>
<para>When <option>s:</option> or <option>d:</option> is specified,
the rate applies per source IP address or per destination IP address
respectively. The <replaceable>name</replaceable> may be chosen by
the user and specifies a hash table to be used to count matching
connections. If not give, the name <emphasis
role="bold">shorewallN</emphasis> (where N is a unique integer) is
assumed. Where more than one rule specifies the same name, the
connections counts for the rules are aggregated and the individual
rates apply to the aggregated count.</para>
<para>Example: <emphasis role="bold">s:ssh:3/min:5</emphasis></para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">USER/GROUP</emphasis> (Optional) -
[<emphasis
role="bold">!</emphasis>][<emphasis>user-name-or-number</emphasis>][<emphasis
role="bold">:</emphasis><emphasis>group-name-or-number</emphasis>][<emphasis
role="bold">+</emphasis><emphasis>program-name</emphasis>]</term>
<listitem>
<para>This column may only be non-empty if the SOURCE is the
firewall itself.</para>
<para>When this column is non-empty, the rule applies only if the
program generating the output is running under the effective
<emphasis>user</emphasis> and/or <emphasis>group</emphasis>
specified (or is NOT running under that id if "!" is given).</para>
<para>Examples:</para>
<variablelist>
<varlistentry>
<term>joe</term>
<listitem>
<para>program must be run by joe</para>
</listitem>
</varlistentry>
<varlistentry>
<term>:kids</term>
<listitem>
<para>program must be run by a member of the 'kids'
group</para>
</listitem>
</varlistentry>
<varlistentry>
<term>!:kids</term>
<listitem>
<para>program must not be run by a member of the 'kids'
group</para>
</listitem>
</varlistentry>
<varlistentry>
<term>+upnpd</term>
<listitem>
<para>program named upnpd</para>
<important>
<para>The ability to specify a program name was removed from
Netfilter in kernel version 2.6.14.</para>
</important>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">MARK</emphasis> - [<emphasis
role="bold">!</emphasis>]<emphasis>value</emphasis>[/<emphasis>mask</emphasis>][<emphasis
role="bold">:C</emphasis>]</term>
<listitem>
<para>Defines a test on the existing packet or connection mark. The
rule will match only if the test returns true.</para>
<para>If you don't want to define a test but need to specify
anything in the following columns, place a "-" in this field.</para>
<variablelist>
<varlistentry>
<term>!</term>
<listitem>
<para>Inverts the test (not equal)</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis>value</emphasis></term>
<listitem>
<para>Value of the packet or connection mark.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis>mask</emphasis></term>
<listitem>
<para>A mask to be applied to the mark before testing.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">:C</emphasis></term>
<listitem>
<para>Designates a connection mark. If omitted, the packet
mark's value is tested.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">CONNLIMIT</emphasis> - [<emphasis
role="bold">!</emphasis>]<emphasis>limit</emphasis>[:<emphasis>mask</emphasis>]</term>
<listitem>
<para>May be used to limit the number of simultaneous connections
from each individual host to <replaceable>limit</replaceable>
connections. Requires connlimit match in your kernel and iptables.
While the limit is only checked on rules specifying CONNLIMIT, the
number of current connections is calculated over all current
connections from the SOURCE host. By default, the limit is applied
to each host but can be made to apply to networks of hosts by
specifying a <replaceable>mask</replaceable>. The
<replaceable>mask</replaceable> specifies the width of a VLSM mask
to be applied to the source address; the number of current
connections is then taken over all hosts in the subnet
<replaceable>source-address</replaceable>/<replaceable>mask</replaceable>.
When<option> !</option> is specified, the rule matches when the
number of connection exceeds the
<replaceable>limit</replaceable>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">TIME</emphasis> -
<emphasis>timeelement</emphasis>[&amp;<emphasis>timelement</emphasis>...]</term>
<listitem>
<para>May be used to limit the rule to a particular time period each
day, to particular days of the week or month, or to a range defined
by dates and times. Requires time match support in your kernel and
iptables.</para>
<para><replaceable>timeelement</replaceable> may be:</para>
<variablelist>
<varlistentry>
<term>timestart=<replaceable>hh</replaceable>:<replaceable>mm</replaceable>[:<replaceable>ss</replaceable>]</term>
<listitem>
<para>Defines the starting time of day.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>timestop=<replaceable>hh</replaceable>:<replaceable>mm</replaceable>[:<replaceable>ss</replaceable>]</term>
<listitem>
<para>Defines the ending time of day.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>utc</term>
<listitem>
<para>Times are expressed in Greenwich Mean Time.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>localtz</term>
<listitem>
<para>Times are expressed in Local Civil Time
(default).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>weekdays=ddd[,ddd]...</term>
<listitem>
<para>where <replaceable>ddd</replaceable> is one of
<option>Mon</option>, <option>Tue</option>,
<option>Wed</option>, <option>Thu</option>,
<option>Fri</option>, <option>Sat</option> or
<option>Sun</option></para>
</listitem>
</varlistentry>
<varlistentry>
<term>monthdays=dd[,dd],...</term>
<listitem>
<para>where <replaceable>dd</replaceable> is an ordinal day of
the month</para>
</listitem>
</varlistentry>
<varlistentry>
<term>datestart=<replaceable>yyyy</replaceable>[-<replaceable>mm</replaceable>[-<replaceable>dd</replaceable>[<option>T</option><replaceable>hh</replaceable>[:<replaceable>mm</replaceable>[:<replaceable>ss</replaceable>]]]]]</term>
<listitem>
<para>Defines the starting date and time.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>datestop=<replaceable>yyyy</replaceable>[-<replaceable>mm</replaceable>[-<replaceable>dd</replaceable>[<option>T</option><replaceable>hh</replaceable>[:<replaceable>mm</replaceable>[:<replaceable>ss</replaceable>]]]]]</term>
<listitem>
<para>Defines the ending date and time.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Examples</title>
<variablelist>
<varlistentry>
<term>Example 1:</term>
<listitem>
<para>Accept SMTP requests from the DMZ to the internet</para>
<programlisting> #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
ACCEPT dmz net tcp smtp</programlisting>
</listitem>
</varlistentry>
<varlistentry>
<term>Example 2:</term>
<listitem>
<para>Forward all ssh and http connection requests from the internet
to local system 192.168.1.3</para>
<programlisting> #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
DNAT net loc:192.168.1.3 tcp ssh,http</programlisting>
</listitem>
</varlistentry>
<varlistentry>
<term>Example 3:</term>
<listitem>
<para>Forward all http connection requests from the internet to
local system 192.168.1.3 with a limit of 3 per second and a maximum
burst of 10<programlisting> #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL RATE
# PORT PORT(S) DEST LIMIT
DNAT net loc:192.168.1.3 tcp http - - 3/sec:10</programlisting></para>
</listitem>
</varlistentry>
<varlistentry>
<term>Example 4:</term>
<listitem>
<para>Redirect all locally-originating www connection requests to
port 3128 on the firewall (Squid running on the firewall system)
except when the destination address is 192.168.2.2</para>
<programlisting> #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
REDIRECT loc 3128 tcp www - !192.168.2.2</programlisting>
</listitem>
</varlistentry>
<varlistentry>
<term>Example 5:</term>
<listitem>
<para>All http requests from the internet to address 130.252.100.69
are to be forwarded to 192.168.1.3</para>
<programlisting> #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
DNAT net loc:192.168.1.3 tcp 80 - 130.252.100.69</programlisting>
</listitem>
</varlistentry>
<varlistentry>
<term>Example 6:</term>
<listitem>
<para>You want to accept SSH connections to your firewall only from
internet IP addresses 130.252.100.69 and 130.252.100.70</para>
<programlisting> #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
ACCEPT net:130.252.100.69,130.252.100.70 $FW \
tcp 22</programlisting>
</listitem>
</varlistentry>
<varlistentry>
<term>Example 7:</term>
<listitem>
<para>You wish to accept connections from the internet to your
firewall on port 2222 and you want to forward them to local system
192.168.1.3, port 22</para>
<programlisting> #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
DNAT net loc:192.168.1.3:22 tcp 2222</programlisting>
</listitem>
</varlistentry>
<varlistentry>
<term>Example 8:</term>
<listitem>
<para>You want to redirect connection requests to port 80 randomly
to the port range 81-90.</para>
<programlisting> #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
REDIRECT net $FW::81-90:random tcp www</programlisting>
</listitem>
</varlistentry>
<varlistentry>
<term>Example 9:</term>
<listitem>
<para>Shorewall does not impose as much structure on the Netfilter
rules in the 'nat' table as it does on those in the filter table. As
a consequence, when using Shorewall versions before 4.1.4, care must
be exercised when using DNAT and REDIRECT rules with zones defined
with wildcard interfaces (those ending with '+'. Here is an
example:</para>
<para><ulink
url="shorewall-zones.html">shorewall-zones</ulink>(8):<programlisting> #ZONE TYPE OPTIONS
fw firewall
net ipv4
dmz ipv4
loc ipv4</programlisting></para>
<para><ulink
url="shorewall-interfaces.html">shorewall-interfaces</ulink>(8):<programlisting> #ZONE INTERFACE BROADCAST OPTIONS
net ppp0
loc eth1 detect
dmz eth2 detect
- ppp+ # Addresses are assigned from 192.168.3.0/24</programlisting></para>
<para><ulink
url="shorewall-hosts.html">shorewall-host</ulink>(8):<programlisting> #ZONE HOST(S) OPTIONS
loc ppp+:192.168.3.0/24</programlisting></para>
<para>rules:</para>
<programlisting> #ACTION SOURCE DEST PROTO DEST
# PORT(S)
REDIRECT loc 3128 tcp 80 </programlisting>
<simpara>Note that it would have been tempting to simply define the
loc zone entirely in shorewall-interfaces(8):</simpara>
<para><programlisting> #******************* INCORRECT *****************
#ZONE INTERFACE BROADCAST OPTIONS
net ppp0
loc eth1 detect
loc ppp+
dmz eth2</programlisting></para>
<para>This would have made it impossible to run a
internet-accessible web server in the DMZ because all traffic
entering ppp+ interfaces would have been redirected to port 3128 on
the firewall and there would have been no net-&gt;fw ACCEPT rule for
that traffic.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>FILES</title>
<para>/etc/shorewall/rules</para>
</refsect1>
<refsect1>
<title>See ALSO</title>
<para>shorewall(8), shorewall-accounting(5), shorewall-actions(5),
shorewall-blacklist(5), shorewall-hosts(5), shorewall-interfaces(5),
shorewall-ipsec(5), shorewall-maclist(5), shorewall-masq(5),
shorewall-nat(5), shorewall-netmap(5), shorewall-params(5),
shorewall-policy(5), shorewall-providers(5), shorewall-proxyarp(5),
shorewall-route_rules(5), shorewall-routestopped(5), shorewall.conf(5),
shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)</para>
</refsect1>
</refentry>
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