forked from extern/shorewall_code
579 lines
22 KiB
XML
579 lines
22 KiB
XML
<?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>shorewall6-masq</refentrytitle>
|
|
|
|
<manvolnum>5</manvolnum>
|
|
|
|
<refmiscinfo>Configuration Files</refmiscinfo>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>masq</refname>
|
|
|
|
<refpurpose>Shorewall6 Masquerade/SNAT definition file</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<cmdsynopsis>
|
|
<command>/etc/shorewall6/masq</command>
|
|
</cmdsynopsis>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para>Use this file to define Source NAT (SNAT). Requires Shorewall 4.5.14
|
|
or later.</para>
|
|
|
|
<warning>
|
|
<para>The entries in this file are order-sensitive. The first entry that
|
|
matches a particular connection will be the one that is used.</para>
|
|
</warning>
|
|
|
|
<warning>
|
|
<para>If you have more than one ISP link, adding entries to this file
|
|
will <emphasis role="bold">not</emphasis> force connections to go out
|
|
through a particular link. You must use entries in <ulink
|
|
url="/manpages6/shorewall6-rtrules.html">shorewall6-rtrules</ulink>(5)
|
|
or PREROUTING entries in <ulink
|
|
url="/manpages6/shorewall6-tcrules.html">shorewall-tcrules</ulink>(5) to
|
|
do that.</para>
|
|
</warning>
|
|
|
|
<para>The columns in the file are as follows.</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><emphasis role="bold">INTERFACE:DEST</emphasis> - {[<emphasis
|
|
role="bold">+</emphasis>]<emphasis>interfacelist</emphasis>|[<emphasis
|
|
role="bold">:</emphasis>[<emphasis>dest-address</emphasis>[<emphasis
|
|
role="bold">,</emphasis><emphasis>dest-address</emphasis>]...[<emphasis>exclusion</emphasis>]]|?COMMENT}</term>
|
|
|
|
<listitem>
|
|
<para>Outgoing <emphasis>interfacelist</emphasis>. This may be a
|
|
comma-separated list of interface names. This is usually your
|
|
internet interface.</para>
|
|
|
|
<para>Each interface must match an entry in <ulink
|
|
url="/manpages6/shorewall6-interfaces.html">shorewall6-interfaces</ulink>(5).
|
|
Shorewall allows loose matches to wildcard entries in <ulink
|
|
url="/manpages6/shorewall6-interfaces.html">shorewall6-interfaces</ulink>(5).
|
|
For example, <filename class="devicefile">ppp0</filename> in this
|
|
file will match a <ulink
|
|
url="/manpages6/shorewall6-interfaces.html">shorewall6-interfaces</ulink>(5)
|
|
entry that defines <filename
|
|
class="devicefile">ppp+</filename>.</para>
|
|
|
|
<para>Where <ulink url="/4.4/MultiISP.html#Shared">more that one
|
|
internet provider share a single interface</ulink>, the provider is
|
|
specified by including the provider name or number in
|
|
parentheses:</para>
|
|
|
|
<programlisting> eth0(Avvanta)</programlisting>
|
|
|
|
<para>In that case, you will want to specify the interface's address
|
|
for that provider in the ADDRESS column.</para>
|
|
|
|
<para>The interface may be qualified by adding the character ":"
|
|
followed by a comma-separated list of destination host or subnet
|
|
addresses to indicate that you only want to change the source IP
|
|
address for packets being sent to those particular destinations.
|
|
Exclusion is allowed (see <ulink
|
|
url="/manpages6/shorewall6-exclusion.html">shorewall6-exclusion</ulink>(5))
|
|
as are ipset names preceded by a plus sign '+'.</para>
|
|
|
|
<para>Comments may be attached to Netfilter rules generated from
|
|
entries in this file through the use of ?COMMENT lines. These lines
|
|
begin with ?COMMENT; the remainder of the line is treated as a
|
|
comment which is attached to subsequent rules until another ?COMMENT
|
|
line is found or until the end of the file is reached. To stop
|
|
adding comments to rules, use a line containing only
|
|
?COMMENT.</para>
|
|
|
|
<para>Beginning with Shorewall 4.6.0, a new syntax is also accepted.
|
|
With the exception of the leading '+', the interfacelist and
|
|
qualifiers may appear within the parentheses of <emphasis
|
|
role="bold">INLINE</emphasis>(...).</para>
|
|
|
|
<para>Example:</para>
|
|
|
|
<programlisting> +INLINE(eth0)</programlisting>
|
|
|
|
<para>When this is done, you may augment the rule generated by
|
|
Shorewall with iptables matches of your own. These matches appear
|
|
after a semicolon (';') at the end of the line.</para>
|
|
|
|
<para>See example 2 below.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">SOURCE</emphasis> (Optional) -
|
|
[<emphasis>interface</emphasis>|<emphasis>address</emphasis>[<emphasis
|
|
role="bold">,</emphasis><emphasis>address</emphasis>][<emphasis>exclusion</emphasis>]]</term>
|
|
|
|
<listitem>
|
|
<para>Set of hosts that you wish to SNAT; one or more host or
|
|
network addresses separated by comma. You may use ipset names
|
|
preceded by a plus sign (+) to specify a set of hosts.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">ADDRESS</emphasis> (Optional) - [<emphasis
|
|
role="bold">-</emphasis>|<emphasis
|
|
role="bold">NONAT</emphasis>|[<emphasis>address-or-address-range</emphasis>[,<emphasis>address-or-address-range</emphasis>]...][:<emphasis>lowport</emphasis><emphasis
|
|
role="bold">-</emphasis><emphasis>highport</emphasis>][<emphasis
|
|
role="bold">:random</emphasis>][:persistent]|<emphasis
|
|
role="bold">detect</emphasis>|<emphasis
|
|
role="bold">random</emphasis>]</term>
|
|
|
|
<listitem>
|
|
<para>If you do not specify an address or address range,
|
|
masquerading will be performed. This requires <firstterm>Masquerade
|
|
Target</firstterm> support in your kernel and ip6tables.</para>
|
|
|
|
<para>If you specify an address here, SNAT will be used and this
|
|
will be the source address.</para>
|
|
|
|
<para>You may also specify a range of up to 256 IP addresses if you
|
|
want the SNAT address to be assigned from that range in a
|
|
round-robin fashion by connection. The range is specified by
|
|
<emphasis>first.ip.in.range</emphasis>-<emphasis>last.ip.in.range</emphasis>.
|
|
You may follow the port range with<emphasis
|
|
role="bold">:random</emphasis> in which case assignment of ports
|
|
from the list will be random. <emphasis
|
|
role="bold">random</emphasis> may also be specified by itself in
|
|
this column in which case random local port assignments are made for
|
|
the outgoing connections.</para>
|
|
|
|
<para>Example:
|
|
[2001:470:a:227::2]-[2001:470:a:227::10]:1000-1010</para>
|
|
|
|
<para>You may follow the port range (or <emphasis
|
|
role="bold">:random</emphasis>) with <emphasis
|
|
role="bold">:persistent</emphasis>. This is only useful when an
|
|
address range is specified and causes a client to be given the same
|
|
source/destination IP pair.</para>
|
|
|
|
<para>This column may not contain DNS Names.</para>
|
|
|
|
<para>Normally, Netfilter will attempt to retain the source port
|
|
number. You may cause netfilter to remap the source port by
|
|
following an address or range (if any) by ":" and a port range with
|
|
the format
|
|
<emphasis>lowport</emphasis>-<emphasis>highport</emphasis>. If this
|
|
is done, you must specify "tcp" or "udp" in the PROTO column.</para>
|
|
|
|
<para>Examples:</para>
|
|
|
|
<programlisting> [2001:470:a:787::2]:5000-6000</programlisting>
|
|
|
|
<para>If you simply place <emphasis role="bold">NONAT</emphasis> in
|
|
this column, no rewriting of the source IP address or port number
|
|
will be performed. This is useful if you want particular traffic to
|
|
be exempt from the entries that follow in the file.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">PROTO</emphasis> (Optional) - {<emphasis
|
|
role="bold">-</emphasis>|[!]{<emphasis>protocol-name</emphasis>|<emphasis>protocol-number</emphasis>}[,...]|+<replaceable>ipset</replaceable>}</term>
|
|
|
|
<listitem>
|
|
<para>If you wish to restrict this entry to a particular protocol
|
|
then enter the protocol name (from protocols(5)) or number
|
|
here.</para>
|
|
|
|
<para>Beginning with Shorewall 4.5.12, this column can accept a
|
|
comma-separated list of protocols.</para>
|
|
|
|
<para>Beginning with Shorewall 4.6.0, an
|
|
<replaceable>ipset</replaceable> name can be specified in this
|
|
column. This is intended to be used with
|
|
<firstterm>bitmap:port</firstterm> ipsets.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">PORT(S)</emphasis> (Optional) -
|
|
{-|[!]<emphasis>port-name-or-number</emphasis>[,<emphasis>port-name-or-number</emphasis>]...|+<replaceable>ipset</replaceable>}</term>
|
|
|
|
<listitem>
|
|
<para>If the PROTO column specifies TCP (6), UDP (17), DCCP (33),
|
|
SCTP (132) or UDPLITE (136) then you may list one or more port
|
|
numbers (or names from services(5)) or port ranges separated by
|
|
commas.</para>
|
|
|
|
<para>Port ranges are of the form
|
|
<emphasis>lowport</emphasis>:<emphasis>highport</emphasis>.</para>
|
|
|
|
<para>Beginning with Shorewall 4.6.0, an
|
|
<replaceable>ipset</replaceable> name can be specified in this
|
|
column. This is intended to be used with
|
|
<firstterm>bitmap:port</firstterm> ipsets.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">IPSEC</emphasis> (Optional) -
|
|
[<emphasis>option</emphasis>[<emphasis
|
|
role="bold">,</emphasis><emphasis>option</emphasis>]...]</term>
|
|
|
|
<listitem>
|
|
<para>If you specify a value other than "-" in this column, you must
|
|
be running kernel 2.6 and your kernel and iptables must include
|
|
policy match support.</para>
|
|
|
|
<para>Comma-separated list of options from the following. Only
|
|
packets that will be encrypted via an SA that matches these options
|
|
will have their source address changed.</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><emphasis
|
|
role="bold">reqid=</emphasis><emphasis>number</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>where <emphasis>number</emphasis> is specified using
|
|
setkey(8) using the 'unique:<emphasis>number</emphasis> option
|
|
for the SPD level.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">spi=</emphasis><number></term>
|
|
|
|
<listitem>
|
|
<para>where <emphasis>number</emphasis> is the SPI of the SA
|
|
used to encrypt/decrypt packets.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">proto=</emphasis><emphasis
|
|
role="bold">ah</emphasis>|<emphasis
|
|
role="bold">esp</emphasis>|<emphasis
|
|
role="bold">ipcomp</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>IPSEC Encapsulation Protocol</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis
|
|
role="bold">mss=</emphasis><emphasis>number</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>sets the MSS field in TCP packets</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">mode=</emphasis><emphasis
|
|
role="bold">transport</emphasis>|<emphasis
|
|
role="bold">tunnel</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>IPSEC mode</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis
|
|
role="bold">tunnel-src=</emphasis><emphasis>address</emphasis>[/<emphasis>mask</emphasis>]</term>
|
|
|
|
<listitem>
|
|
<para>only available with mode=tunnel</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis
|
|
role="bold">tunnel-dst=</emphasis><emphasis>address</emphasis>[/<emphasis>mask</emphasis>]</term>
|
|
|
|
<listitem>
|
|
<para>only available with mode=tunnel</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">strict</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>Means that packets must match all rules.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">next</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>Separates rules; can only be used with strict</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">yes</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>When used by itself, causes all traffic that will be
|
|
encrypted/encapsulated to match the rule.</para>
|
|
</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">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>Only locally-generated connections will match if this column
|
|
is non-empty.</para>
|
|
|
|
<para>When this column is non-empty, the rule matches 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">SWITCH -
|
|
[!]<replaceable>switch-name</replaceable>[={0|1}]</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>Added in Shorewall 4.5.1 and allows enabling and disabling the
|
|
rule without requiring <command>shorewall restart</command>.</para>
|
|
|
|
<para>The rule is enabled if the value stored in
|
|
<filename>/proc/net/nf_condition/<replaceable>switch-name</replaceable></filename>
|
|
is 1. The rule is disabled if that file contains 0 (the default). If
|
|
'!' is supplied, the test is inverted such that the rule is enabled
|
|
if the file contains 0.</para>
|
|
|
|
<para>Within the <replaceable>switch-name</replaceable>, '@0' and
|
|
'@{0}' are replaced by the name of the chain to which the rule is a
|
|
added. The <replaceable>switch-name</replaceable> (after '@...'
|
|
expansion) must begin with a letter and be composed of letters,
|
|
decimal digits, underscores or hyphens. Switch names must be 30
|
|
characters or less in length.</para>
|
|
|
|
<para>Switches are normally <emphasis role="bold">off</emphasis>. To
|
|
turn a switch <emphasis role="bold">on</emphasis>:</para>
|
|
|
|
<simplelist>
|
|
<member><command>echo 1 >
|
|
/proc/net/nf_condition/<replaceable>switch-name</replaceable></command></member>
|
|
</simplelist>
|
|
|
|
<para>To turn it <emphasis role="bold">off</emphasis> again:</para>
|
|
|
|
<simplelist>
|
|
<member><command>echo 0 >
|
|
/proc/net/nf_condition/<replaceable>switch-name</replaceable></command></member>
|
|
</simplelist>
|
|
|
|
<para>Switch settings are retained over <command>shorewall
|
|
restart</command>.</para>
|
|
|
|
<para>Beginning with Shorewall 4.5.10, when the
|
|
<replaceable>switch-name</replaceable> is followed by
|
|
<option>=0</option> or <option>=1</option>, then the switch is
|
|
initialized to off or on respectively by the
|
|
<command>start</command> command. Other commands do not affect the
|
|
switch setting.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">ORIGINAL DEST</emphasis> (origdest) -
|
|
[<emphasis
|
|
role="bold">-</emphasis>|<emphasis>address</emphasis>[,<emphasis>address</emphasis>]...[<emphasis>exclusion</emphasis>]|<emphasis>exclusion</emphasis>]</term>
|
|
|
|
<listitem>
|
|
<para>(Optional) 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. It is useful for specifying that SNAT should
|
|
occur only for connections that were acted on by a DNAT when they
|
|
entered the firewall.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis role="bold">PROBABILITY</emphasis> -
|
|
[<replaceable>probability</replaceable>]</term>
|
|
|
|
<listitem>
|
|
<para>Added in Shorewall 5.0.0. When non-empty, requires the
|
|
<firstterm>Statistics Match</firstterm> capability in your kernel
|
|
and ip6tables and causes the rule to match randomly but with the
|
|
given <replaceable>probability</replaceable>. The
|
|
<replaceable>probability</replaceable> is a number 0 <
|
|
<replaceable>probability</replaceable> <= 1 and may be expressed
|
|
at up to 8 decimal points of precision.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Examples</title>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>Example 1:</term>
|
|
|
|
<listitem>
|
|
<para>You have a simple 'masquerading' setup where eth0 connects to
|
|
a DSL or cable modem and eth1 connects to your local network with
|
|
subnet 2001:470:b:787::0/64</para>
|
|
|
|
<para>Your entry in the file will be:</para>
|
|
|
|
<programlisting> #INTERFACE SOURCE ADDRESS
|
|
eth0 2001:470:b:787::0/64 -</programlisting>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>Example 2:</term>
|
|
|
|
<listitem>
|
|
<para>Your sit1 interface has two public IP addresses:
|
|
2001:470:a:227::1 and 2001:470:b:227::1. You want to use the
|
|
iptables statistics match to masquerade outgoing connections evenly
|
|
between these two addresses.</para>
|
|
|
|
<programlisting>/etc/shorewall/masq:
|
|
|
|
#INTERFACE SOURCE ADDRESS
|
|
INLINE(sit1) 0.0.0.0/0 2001:470:a:227::1 ; -m statistic --mode random --probability 0.50
|
|
sit1 0.0.0.0/0 2001:470:a:227::2
|
|
</programlisting>
|
|
|
|
<para>If INLINE_MATCHES=Yes in <ulink
|
|
url="/manpages6/shorewall6.conf.html">shorewall6.conf</ulink>(5),
|
|
then these rules may be specified as follows:</para>
|
|
|
|
<programlisting>/etc/shorewall/masq:
|
|
|
|
#INTERFACE SOURCE ADDRESS
|
|
sit1 0.0.0.0/0 2001:470:a:227::1 ; -m statistic --mode random --probability 0.50
|
|
sit1 0.0.0.0/0 2001:470:a:227::2
|
|
</programlisting>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>FILES</title>
|
|
|
|
<para>/etc/shorewall6/masq</para>
|
|
</refsect1>
|
|
</refentry>
|