<?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-conntrack</refentrytitle> <manvolnum>5</manvolnum> </refmeta> <refnamediv> <refname>conntrack</refname> <refpurpose>shorewall conntrack file</refpurpose> </refnamediv> <refsynopsisdiv> <cmdsynopsis> <command>/etc/shorewall/conntrack</command> </cmdsynopsis> </refsynopsisdiv> <refsect1> <title>Description</title> <para>The original intent of the <emphasis role="bold">notrack</emphasis> file was to exempt certain traffic from Netfilter connection tracking. Traffic matching entries in the file were not to be tracked.</para> <para>The role of the file was expanded in Shorewall 4.4.27 to include all rules that can be added in the Netfilter <emphasis role="bold">raw</emphasis> table. In 4.5.7, the file's name was changed to <emphasis role="bold">conntrack</emphasis>.</para> <para>The file supports two different column layouts: FORMAT 1, FORMAT 2, and FORMAT 3, FORMAT 1 being the default. The three differ as follows:</para> <itemizedlist> <listitem> <para>in FORMAT 2 and 3, there is an additional leading ACTION column.</para> </listitem> <listitem> <para>in FORMAT 3, the SOURCE column accepts no zone name; rather the ACTION column allows a SUFFIX that determines the chain(s) that the generated rule will be added to.</para> </listitem> </itemizedlist> <para>When an entry in the following form is encountered, the format of the following entries are assumed to be of the specified <replaceable>format</replaceable>.</para> <simplelist> <member><emphasis role="bold">[?]FORMAT</emphasis> <replaceable>format</replaceable></member> </simplelist> <para>where <replaceable>format</replaceable> is either <emphasis role="bold">1</emphasis>,<emphasis role="bold">2</emphasis> or <emphasis role="bold">3</emphasis>.</para> <para>Format 3 was introduced in Shorewall 4.5.10. The optional '?' was introduced in Shorewall 4.5.11 and ?FORMAT is the preferred form; the form without the '?' is deprecated.</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 the word 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 with only the word COMMENT.</para> <note> <para>Beginning with Shorewall 4.5.11, ?COMMENT is a synonym for COMMENT and is preferred.</para> </note> <para>The columns in the file are as follows (where the column name is followed by a different name in parentheses, the different name is used in the alternate specification syntax).</para> <variablelist> <varlistentry> <term><emphasis role="bold">ACTION</emphasis> - {<emphasis role="bold">NOTRACK</emphasis>|<emphasis role="bold">CT</emphasis>:<emphasis role="bold">helper</emphasis>:<replaceable>name</replaceable>[(<replaceable>arg</replaceable>=<replaceable>val</replaceable>[,...])|<emphasis role="bold">CT:notrack</emphasis>|DROP}[:<replaceable>chain-designator</replaceable>]</term> <listitem> <para>This column is only present when FORMAT >= 2. Values other than NOTRACK or DROP require <firstterm>CT Target </firstterm>support in your iptables and kernel.</para> <itemizedlist> <listitem> <para><option>NOTRACK</option> or <option>CT:notrack</option></para> <para>Disables connection tracking for this packet.</para> </listitem> <listitem> <para><option>DROP</option></para> <para>Added in Shorewall 4.5.10. Silently discard the packet.</para> </listitem> <listitem> <para><option>helper</option>:<replaceable>name</replaceable></para> <para>Attach the helper identified by the <replaceable>name</replaceable> to this connection. This is more flexible than loading the conntrack helper with preset ports.</para> <para>At this writing, the available helpers are:</para> <variablelist> <varlistentry> <term>amanda</term> <listitem> <para>Requires that the amanda netfilter helper is present.</para> </listitem> </varlistentry> <varlistentry> <term>ftp</term> <listitem> <para>Requires that the FTP netfilter helper is present.</para> </listitem> </varlistentry> <varlistentry> <term>irc</term> <listitem> <para>Requires that the IRC netfilter helper is present.</para> </listitem> </varlistentry> <varlistentry> <term>netbios-ns</term> <listitem> <para>Requires that the netbios_ns (sic) helper is present.</para> </listitem> </varlistentry> <varlistentry> <term>RAS and Q.931</term> <listitem> <para>These require that the H323 netfilter helper is present.</para> </listitem> </varlistentry> <varlistentry> <term>pptp</term> <listitem> <para>Requires that the pptp netfilter helper is present.</para> </listitem> </varlistentry> <varlistentry> <term></term> <listitem> <para></para> </listitem> </varlistentry> <varlistentry> <term>sane</term> <listitem> <para>Requires that the SANE netfilter helper is present.</para> </listitem> </varlistentry> <varlistentry> <term>sip</term> <listitem> <para>Requires that the SIP netfilter helper is present.</para> </listitem> </varlistentry> <varlistentry> <term>snmp</term> <listitem> <para>Requires that the SNMP netfilter helper is present.</para> </listitem> </varlistentry> <varlistentry> <term>tftp</term> <listitem> <para>Requires that the TFTP netfilter helper is present.</para> </listitem> </varlistentry> </variablelist> <para>May be followed by an option list of <replaceable>arg</replaceable>=<replaceable>val</replaceable> pairs in parentheses:</para> <itemizedlist> <listitem> <para><option>ctevents</option>=<replaceable>event</replaceable>[,...]</para> <para>Only generate the specified conntrack events for this connection. Possible event types are: <emphasis role="bold">new</emphasis>, <emphasis role="bold">related</emphasis>, <emphasis role="bold">destroy</emphasis>, <emphasis role="bold">reply</emphasis>, <emphasis role="bold">assured</emphasis>, <emphasis role="bold">protoinfo</emphasis>, <emphasis role="bold">helper</emphasis>, <emphasis role="bold">mark</emphasis> (this is connection mark, not packet mark), <emphasis role="bold">natseqinfo</emphasis>, and <emphasis role="bold">secmark</emphasis>. If more than one <emphasis>event</emphasis> is listed, the <replaceable>event</replaceable> list must be enclosed in parentheses (e.g., ctevents=(new,related)).</para> </listitem> <listitem> <para><option>expevents</option><option>=new</option></para> <para>Only generate a <emphasis role="bold">new</emphasis> expectation events for this connection.</para> </listitem> </itemizedlist> </listitem> </itemizedlist> <para>When FORMAT = 1, this column is not present and the rule is processed as if NOTRACK had been entered in this column.</para> <para>Beginning with Shorewall 4.5.10, when FORMAT = 3, this column can end with a colon followed by a <replaceable>chain-designator</replaceable>. The <replaceable>chain-designator</replaceable> can be one of the following:</para> <variablelist> <varlistentry> <term>P</term> <listitem> <para>The rule is added to the raw table PREROUTING chain. This is the default if no <replaceable>chain-designator</replaceable> is present.</para> </listitem> </varlistentry> <varlistentry> <term>O</term> <listitem> <para>The rule is added to the raw table OUTPUT chain.</para> </listitem> </varlistentry> <varlistentry> <term>PO or OP</term> <listitem> <para>The rule is added to the raw table PREROUTING and OUTPUT chains.</para> </listitem> </varlistentry> </variablelist> </listitem> </varlistentry> <varlistentry> <term>SOURCE (formats 1 and 2) ‒ {<emphasis>zone</emphasis>[:<emphasis>interface</emphasis>][:<emphasis>address-list</emphasis>]|COMMENT}</term> <listitem> <para>where <replaceable>zone</replaceable> is the name of a zone, <replaceable>interface</replaceable> is an interface to that zone, and <replaceable>address-list</replaceable> is a comma-separated list of addresses (may contain exclusion - see <ulink url="shorewall-exclusion.html">shorewall-exclusion</ulink> (5)).</para> <para>Beginning with Shorewall 4.5.7, <option>all</option> can be used as the <replaceable>zone</replaceable> name to mean <firstterm>all zones</firstterm>.</para> <para>Beginning with Shorewall 4.5.10, <option>all-</option> can be used as the <replaceable>zone</replaceable> name to mean all <firstterm>off-firewall zone</firstterm>s.</para> </listitem> </varlistentry> <varlistentry> <term>SOURCE (format 3) ‒ {-|<emphasis>interface</emphasis>[:<emphasis>address-list</emphasis>]|<replaceable>address-list</replaceable>}</term> <listitem> <para>Where <replaceable>interface</replaceable> is an interface to that zone, and <replaceable>address-list</replaceable> is a comma-separated list of addresses (may contain exclusion - see <ulink url="shorewall-exclusion.html">shorewall-exclusion</ulink> (5)).</para> <para>COMMENT is only allowed in format 1; the remainder of the line is treated as a comment that will be associated with the generated rule(s).</para> </listitem> </varlistentry> <varlistentry> <term>DEST ‒ {-|<emphasis>interface</emphasis>[:<emphasis>address-list</emphasis>]|<replaceable>address-list</replaceable>}</term> <listitem> <para>where <replaceable>address-list</replaceable> is a comma-separated list of addresses (may contain exclusion - see <ulink url="shorewall-exclusion.html">shorewall6-exclusion</ulink> (5)).</para> </listitem> </varlistentry> <varlistentry> <term>PROTO ‒ <replaceable>protocol-name-or-number</replaceable>[,...]</term> <listitem> <para>A protocol name from <filename>/etc/protocols</filename> or a protocol number.</para> <para>Beginning with Shorewall 4.5.12, this column is labeled <emphasis role="bold">PROTOS</emphasis> and can accept a comma-separated list of protocols. Either <emphasis role="bold">proto</emphasis> or <emphasis role="bold">protos</emphasis> is accepted in the alternate input format.</para> </listitem> </varlistentry> <varlistentry> <term>DEST PORT(S) (dport) - port-number/service-name-list</term> <listitem> <para>A comma-separated list of port numbers and/or service names from <filename>/etc/services</filename>. May also include port ranges of the form <replaceable>low-port</replaceable>:<replaceable>high-port</replaceable> if your kernel and iptables include port range support.</para> </listitem> </varlistentry> <varlistentry> <term>SOURCE PORT(S) (sport) - port-number/service-name-list</term> <listitem> <para>A comma-separated list of port numbers and/or service names from <filename>/etc/services</filename>. May also include port ranges of the form <replaceable>low-port</replaceable>:<replaceable>high-port</replaceable> if your kernel and iptables include port range support.</para> <para>Beginning with Shorewall 4.5.15, you may place '=' in this column, provided that the DEST PORT(S) column is non-empty. This causes the rule to match when either the source port or the destination port in a packet matches one of the ports specified in DEST PORTS(S). Use of '=' requires multiport match in your iptables and kernel.</para> </listitem> </varlistentry> <varlistentry> <term>USER/GROUP (user) ‒ [<replaceable>user</replaceable>][:<replaceable>group</replaceable>]</term> <listitem> <para>May only be specified if the SOURCE <replaceable>zone</replaceable> is $FW. Specifies the effective user id and or group id of the process sending the traffic.</para> </listitem> </varlistentry> <varlistentry> <term><emphasis role="bold">SWITCH - [!]<replaceable>switch-name</replaceable>[={0|1}]</emphasis></term> <listitem> <para>Added in Shorewall 4.5.10 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>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> </variablelist> </refsect1> <refsect1> <title>EXAMPLE</title> <para>Example 1:</para> <programlisting>#ACTION SOURCE DEST PROTO DEST SOURCE USER/GROUP # PORT(S) PORT(S) CT:helper:ftp(expevents=new) fw - tcp 21 </programlisting> <para>Example 2 (Shorewall 4.5.10 or later):</para> <para>Drop traffic to/from all zones to IP address 1.2.3.4</para> <programlisting>FORMAT 2 #ACTION SOURCE DEST PROTO DEST SOURCE USER/GROUP # PORT(S) PORT(S) DROP all-:1.2.3.4 - DROP all 1.2.3.4</programlisting> <para>or<programlisting>FORMAT 3 #ACTION SOURCE DEST PROTO DEST SOURCE USER/GROUP # PORT(S) PORT(S) DROP:P 1.2.3.4 - DROP:PO - 1.2.3.4 </programlisting></para> </refsect1> <refsect1> <title>FILES</title> <para>/etc/shorewall/notrack</para> </refsect1> <refsect1> <title>See ALSO</title> <para><ulink url="http://shorewall.net/configuration_file_basics.htm#Pairs">http://shorewall.net/configuration_file_basics.htm#Pairs</ulink></para> <para>shorewall(8), shorewall-accounting(5), shorewall-actions(5), shorewall-blacklist(5), shorewall-hosts(5), shorewall_interfaces(5), shorewall-ipsets(5), shorewall-masq(5), shorewall-nat(5), shorewall-netmap(5), shorewall-params(5), shorewall-policy(5), shorewall-providers(5), shorewall-proxyarp(5), shorewall-rtrules(5), shorewall-routestopped(5), shorewall-rules(5), shorewall.conf(5), shorewall-secmarks(5), shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5), shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)</para> </refsect1> </refentry>