shorewall_code/manpages/shorewall.conf.xml
2006-11-21 18:45:12 +00:00

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<?xml version="1.0" encoding="UTF-8"?>
<refentry>
<refmeta>
<refentrytitle>shorewall.conf</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>shorewall.conf</refname>
<refpurpose>Shorewall global configuration file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>/etc/shorewall/shorewall.conf</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>This file sets options that apply to Shorewall as a whole.</para>
<para>The file consists of Shell comments (lines beginning with '#'),
blank lines and assignment statements
(<emphasis>variable</emphasis>=<emphasis>value</emphasis>). Each
variable's setting is preceded by comments that describe the variable and
it's effect.</para>
</refsect1>
<refsect1>
<title>OPTIONS</title>
<para>Many options have as their value a <emphasis>log-level</emphasis>.
Log levels are a method of describing to syslog (8) the importance of a
message and a number of parameters in this file have log levels as their
value.</para>
<para> These levels are defined by syslog and are used to determine the
destination of the messages through entries in /etc/syslog.conf (5). The
syslog documentation refers to these as "priorities"; Netfilter calls them
"levels" and Shorewall also uses that term.</para>
<para>Valid levels are:</para>
<programlisting> 7 debug
6 info
5 notice
4 warning
3 err
2 crit
1 alert
0 emerg</programlisting>
<para>For most Shorewall logging, a level of 6 (info) is appropriate.
Shorewall log messages are generated by NetFilter and are logged using
facility 'kern' and the level that you specifify. If you are unsure of the
level to choose, 6 (info) is a safe bet. You may specify levels by name or
by number.</para>
<para>If you have built your kernel with ULOG target support, you may also
specify a log level of ULOG (must be all caps). Rather than log its
messages to syslogd, Shorewall will direct netfilter to log the messages
via the ULOG target which will send them to a process called 'ulogd'.
ulogd is available with most Linux distributions (although it probably
isn't installed by default). Ulogd is also available from
http://www.gnumonks.org/projects/ulogd and can be configured to log all
Shorewall message to their own log file</para>
<para>The following options may be set in shorewall.conf.</para>
<variablelist>
<varlistentry>
<term><emphasis
role="bold">ACCEPT_DEFAULT=</emphasis>{<emphasis>action</emphasis>|<emphasis>macro</emphasis>|<emphasis
role="bold">none</emphasis>}</term>
<listitem>
<para></para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">DROP_DEFAULT=</emphasis>{<emphasis>action</emphasis>|<emphasis>macro</emphasis>|<emphasis
role="bold">none</emphasis>}</term>
<listitem>
<para></para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">REJECT_DEFAULT=</emphasis>{<emphasis>action</emphasis>|<emphasis>macro</emphasis>|<emphasis
role="bold">none</emphasis>}</term>
<listitem>
<para></para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">QUEUE_DEFAULT=</emphasis>{<emphasis>action</emphasis>|<emphasis>macro</emphasis>|<emphasis
role="bold">none</emphasis>}</term>
<listitem>
<para>In earlier Shorewall versions, a "default action" for DROP and
REJECT policies was specified in the file
/usr/share/shorewall/actions.std.</para>
<para>To allow for default rules to be applied when USE_ACTIONS=No,
the DROP_DEFAULT, REJECT_DEFAULT, ACCEPT_DEFAULT and QUEUE_DEFAULT
options have been added.</para>
<para>DROP_DEFAULT describes the rules to be applied before a
connection request is dropped by a DROP policy; REJECT_DEFAULT
describes the rules to be applied if a connection request is
rejected by a REJECT policy. The other two are similar for ACCEPT
and QUEUE policies.</para>
<para>The value applied to these may be:</para>
<simplelist>
<member>a) The name of an action.</member>
<member>b) The name of a macro</member>
<member>c) <emphasis role="bold">None</emphasis> or <emphasis
role="bold">none</emphasis></member>
</simplelist>
<para>The default values are:</para>
<simplelist>
<member>DROP_DEFAULT="Drop"</member>
<member>REJECT_DEFAULT="Reject"</member>
<member>ACCEPT_DEFAULT="none"</member>
<member>QUEUE_DEFAULT="none"</member>
</simplelist>
<para>If USE_ACTIONS=Yes, then these values refer to action.Drop and
action.Reject respectively. If USE_ACTIONS=No, then these values
refer to macro.Drop and macro.Reject.</para>
<para>If you set the value of either option to "None" then no
default action will be used and the default action or macro must be
specified in shorewall-policy(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ADD_IP_ALIASES=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>This parameter determines whether Shorewall automatically adds
the external address(es) in shorewall.nat(5). If the variable is set
to <emphasis role="bold">Yes</emphasis> or <emphasis
role="bold">yes</emphasis> then Shorewall automatically adds these
aliases. If it is set to <emphasis role="bold">No</emphasis> or
<emphasis role="bold">no</emphasis>, you must add these aliases
yourself using your distribution's network configuration
tools.</para>
<para>If this variable is not set or is given an empty value
(ADD_IP_ALIASES="") then ADD_IP_ALIASES=Yes is assumed.</para>
<warning>
<para>Addresses added by ADD_IP_ALIASES=Yes are deleted and
re-added during shorewall restart. As a consequence, connections
using those addresses may be severed.</para>
</warning>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ADD_SNAT_ALIASES=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>This parameter determines whether Shorewall automatically adds
the SNAT ADDRESS in /etc/shorewall/masq. If the variable is set to
<emphasis role="bold">Yes</emphasis> or <emphasis
role="bold">yes</emphasis> then Shorewall automatically adds these
addresses. If it is set to <emphasis role="bold">No</emphasis> or
<emphasis role="bold">no</emphasis>, you must add these addresses
yourself using your distribution's network configuration
tools.</para>
<para>If this variable is not set or is given an empty value
(ADD_SNAT_ALIASES="") then ADD_SNAT_ALIASES=No is assumed.</para>
<warning>
<para>Addresses added by ADD_SNAT_ALIASES=Yes are deleted and
re-added during shorewall restart. As a consequence, connections
using those addresses may be severed.</para>
</warning>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ADMINISABSENTMINDED=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>The value of this variable affects Shorewall's stopped state.
When ADMINISABSENTMINDES=No, only traffic to/from those addresses
listed in shorewall-routestopped(5) is accepted when Shorewall is
stopped. When ADMINISABSENTMINDED=Yes, in addition to traffic
to/from addresses in shorewall-routestopped(5), connections that
were active when Shorewall stopped continue to work and all new
connections from the firewall system itself are allowed. If this
variable is not set or is given the empty value then
ADMINISABSENTMINDED=No is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">BLACKLIST_DISPOSITION=</emphasis>[<emphasis
role="bold">DROP</emphasis>|<emphasis
role="bold">REJECT</emphasis>]</term>
<listitem>
<para>This parameter determines the disposition of packets from
blacklisted hosts. It may have the value DROP if the packets are to
be dropped or REJECT if the packets are to be replied with an ICMP
port unreachable reply or a TCP RST (tcp only). If you do not assign
a value or if you assign an empty value then DROP is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">BLACKLIST_LOGLEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>
<listitem>
<para>This parameter determines if packets from blacklisted hosts
are logged and it determines the syslog level that they are to be
logged at. Its value is a syslog level (Example:
BLACKLIST_LOGLEVEL=debug). If you do not assign a value or if you
assign an empty value then packets from blacklisted hosts are not
logged.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">BRIDGING=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>When set to <emphasis role="bold">Yes</emphasis> or <emphasis
role="bold">yes</emphasis>, enables Shorewall Bridging
support.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">CLAMPMSS=[</emphasis><emphasis
role="bold">Yes</emphasis>|<emphasis
role="bold">No</emphasis>|<emphasis>value</emphasis>]</term>
<listitem>
<para>This parameter enables the TCP Clamp MSS to PMTU feature of
Netfilter and is usually required when your internet connection is
through PPPoE or PPTP. If set to <emphasis
role="bold">Yes</emphasis> or <emphasis role="bold">yes</emphasis>,
the feature is enabled. If left blank or set to <emphasis
role="bold">No</emphasis> or <emphasis role="bold">no</emphasis>,
the feature is not enabled.</para>
<note>
<para>This option requires CONFIG_IP_NF_TARGET_TCPMSS in your
kernel.</para>
</note>
<para>You may also set CLAMPMSS to a numeric
<emphasis>value</emphasis> (e.g., CLAMPMSS=1400). This will set the
MSS field in TCP SYN packets going through the firewall to the
<emphasis>value</emphasis> that you specify.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">CLEAR_TC=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>If this option is set to <emphasis role="bold">No</emphasis>
then Shorewall won't clear the current traffic control rules during
[re]start. This setting is intended for use by people that prefer to
configure traffic shaping when the network interfaces come up rather
than when the firewall is started. If that is what you want to do,
set TC_ENABLED=Yes and CLEAR_TC=No and do not supply an
/etc/shorewall/tcstart file. That way, your traffic shaping rules
can still use the “fwmark” classifier based on packet marking
defined in shorewall-tcrules(5). If not specified, CLEAR_TC=Yes is
assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>CONFIG_PATH=[<emphasis>directory</emphasis>[:<emphasis>directory</emphasis>]...]</term>
<listitem>
<para>Specifies where configuration files other than shorewall.conf
may be found. CONFIG_PATH is specifies as a list of directory names
separated by colons (":"). When looking for a configuration file
other than shorewall.conf:</para>
<itemizedlist>
<listitem>
<para>If the command is "try" or if "-c &lt;configuration
directory&gt;" was specified in the command then the directory
given in the command is searched first.</para>
</listitem>
<listitem>
<para>Next, each directory in the CONFIG_PATH setting is
searched in sequence.</para>
</listitem>
</itemizedlist>
<para>If CONFIG_PATH is not given or if it is set to the empty value
then the contents of /usr/share/shorewall/configpath are used. As
released from shorewall.net, that file sets the CONFIG_PATH to
/etc/shorewall:/usr/share/shorewall but your particular distribution
may set it differently. See the output of shorewall show config for
the default on your system.</para>
<para>Note that the setting in /usr/share/shorewall/configpath is
always used to locate shorewall.conf.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DELAYBLACKLISTLOAD=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>Users with a large static black list (shorewall-blacklist(5))
may want to set the DELAYBLACKLISTLOAD option to <emphasis
role="bold">Yes</emphasis>. 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 <emphasis
role="bold">shorewall</emphasis> [<emphasis
role="bold">re</emphasis>]<emphasis
role="bold">start</emphasis>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DETECT_DNAT_ADDRS=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>If set to <emphasis role="bold">Yes</emphasis> or <emphasis
role="bold">yes</emphasis>, Shorewall will detect the first IP
address of the interface to the source zone and will include this
address in DNAT rules as the original destination IP address. If set
to <emphasis role="bold">No</emphasis> or <emphasis
role="bold">no</emphasis>, Shorewall will not detect this address
and any destination IP address will match the DNAT rule. If not
specified or empty, “DETECT_DNAT_ADDRS=Yes” is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DYNAMIC_ZONES=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>When set to <emphasis role="bold">Yes</emphasis> or <emphasis
role="bold">yes</emphasis>, enables dynamic zones. DYNAMIC_ZONES=Yes
is not allowed in configurations that will run under Shorewall
Lite.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">FASTACCEPT=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>Normally, Shorewall accepting ESTABLISHED/RELATED packets
until these packets reach the chain in which the original connection
was accepted. So for packets going from the 'loc' zone to the 'net'
zone, ESTABLISHED/RELATED packets are ACCEPTED in the 'loc2net'
chain.</para>
<para>If you set FASTACCEPT=Yes, then ESTABLISHED/RELEATED packets
are accepted early in the INPUT, FORWARD and OUTPUT chains. If you
set FASTACCEPT=Yes then you may not include rules in the ESTABLISHED
or RELATED sections of shorewall-rules(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">HIGH_ROUTE_MARKS=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>Prior to version 3.2.0, it was not possible to use connection
marking in /etc/shorewall/tcrules if you have a multi-ISP
configuration that uses the track option.</para>
<para>Beginning with release 3.2.0, you may now set
HIGH_ROUTE_MARKS=Yes in to effectively divide the packet mark and
connection mark into two 8-byte mark fields.</para>
<para>When you do this:</para>
<orderedlist numeration="loweralpha">
<listitem>
<para>The MARK field in the providers file must have a value
that is less than 65536 and that is a multiple of 256 (using hex
representation, the values are 0x0100-0xFF00 with the low-order
8 bits being zero).</para>
</listitem>
<listitem>
<para>You may only set those mark values in the PREROUTING
chain.</para>
</listitem>
<listitem>
<para>Marks used for traffic shaping must still be in the range
of 1-255 and may still not be set in the PREROUTING
chain.</para>
</listitem>
<listitem>
<para>When you SAVE or RESTORE in tcrules, only the TC mark
value is saved or restored. Shorewall handles saving and
restoring the routing (provider) marks.</para>
</listitem>
</orderedlist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">IMPLICIT_CONTINUE=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>When this option is set to <emphasis
role="bold">Yes</emphasis>, it causes subzones to be treated
differently with respect to policies.</para>
<para>Subzones are defined by following their name with ":" and a
list of parent zones (in /etc/shorewall/zones). Normally, you want
to have a set of special rules for the subzone and if a connection
doesn't match any of those subzone-specific rules then you want the
parent zone rules and policies to be applied. With
IMPLICIT_CONTINUE=Yes, that happens automatically.</para>
<para>If IMPLICIT_CONTINUE=No or if IMPLICIT_CONTINUE is not set,
then subzones are not subject to this special treatment. With
IMPLICIT_CONTINUE=Yes, an implicit CONTINUE policy may be overridden
by including an explicit policy (one that does not specify "all" in
either the SOURCE or the DEST columns).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">IP_FORWARDING=</emphasis>[<emphasis
role="bold">On</emphasis>|<emphasis
role="bold">Off</emphasis>|<emphasis
role="bold">Keep</emphasis>]</term>
<listitem>
<para>This parameter determines whether Shorewall enables or
disables IPV4 Packet Forwarding (/proc/sys/net/ipv4/ip_forward).
Possible values are:</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">On</emphasis> or <emphasis
role="bold">on</emphasis></term>
<listitem>
<para>packet forwarding will be enabled.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">Off</emphasis> or <emphasis
role="bold">off</emphasis></term>
<listitem>
<para>packet forwarding will be disabled.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">Keep</emphasis> or <emphasis
role="bold">keep</emphasis></term>
<listitem>
<para>Shorewall will neither enable nor disable packet
forwarding.</para>
</listitem>
</varlistentry>
</variablelist>
<para>If this variable is not set or is given an empty value
(IP_FORWARD="") then IP_FORWARD=On is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">IPSECFILE=</emphasis>{<emphasis
role="bold">zones</emphasis>|<emphasis
role="bold">ipsec</emphasis>}</term>
<listitem>
<para>This should be set to <emphasis role="bold">zones</emphasis>
for all new Shorewall installations. IPSECFILE=ipsec is only used
for compatibility with pre-Shorewall-3.0 configurations.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">IPTABLES=</emphasis>[<emphasis>pathname</emphasis>]</term>
<listitem>
<para>This parameter names the iptables executable to be used by
Shorewall. If not specified or if specified as a null value, then
the iptables executable located using the PATH option is
used.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">LOG_MARTIANS=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>If set to <emphasis role="bold">Yes</emphasis> or <emphasis
role="bold">yes</emphasis>, sets
/proc/sys/net/ipv4/conf/all/log_martians and
/proc/sys/net/ipv4/conf/default/log_martians to 1. Default is
<emphasis role="bold">No</emphasis> which sets both of the above to
zero. If you do not enable martian logging for all interfaces, you
may still enable it for individual interfaces using the <emphasis
role="bold">logmartians</emphasis> interface option in
shorewall-interfaces(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">LOGALLNEW=</emphasis>[<emphasis>log-level</emphasis>]</term>
<listitem>
<para>When set to a log level, this option causes Shorewall to
generate a logging rule as the first rule in each builtin
chain.</para>
<itemizedlist>
<listitem>
<para>The table name is used as the chain name in the log
prefix.</para>
</listitem>
<listitem>
<para>The chain name is used as the target in the log
prefix.</para>
</listitem>
</itemizedlist>
<para>For example, using the default LOGFORMAT, the log prefix for
logging from the nat table's PREROUTING chain is:</para>
<programlisting> Shorewall:nat:PREROUTING
</programlisting>
<important>
<para>There is no rate limiting on these logging rules so use
LOGALLNEW at your own risk; it may cause high CPU and disk
utilization and you may not be able to control your firewall after
you enable this option.</para>
</important>
<caution>
<para>Do not use this option if the resulting log messages will be
sent to another system.</para>
</caution>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">LOGFILE=</emphasis>[<emphasis>pathname</emphasis>]</term>
<listitem>
<para>This parameter tells the /sbin/shorewall program where to look
for Shorewall messages when processing the <emphasis
role="bold">dump</emphasis>, <emphasis
role="bold">logwatch</emphasis>, <emphasis role="bold">show
log</emphasis>, and <emphasis role="bold">hits</emphasis> commands.
If not assigned or if assigned an empty value, /var/log/messages is
assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">LOGFORMAT=</emphasis>[<emphasis
role="bold">"</emphasis><emphasis>formattemplate</emphasis><emphasis
role="bold">"</emphasis>]</term>
<listitem>
<para>The value of this variable generate the --log-prefix setting
for Shorewall logging rules. It contains a “printf” formatting
template which accepts three arguments (the chain name, logging rule
number (optional) and the disposition). To use LOGFORMAT with
fireparse, set it as:</para>
<programlisting> LOGFORMAT="fp=%s:%d a=%s "</programlisting>
<para>If the LOGFORMAT value contains the substring “%d” then the
logging rule number is calculated and formatted in that position; if
that substring is not included then the rule number is not included.
If not supplied or supplied as empty (LOGFORMAT="") then
“Shorewall:%s:%s:” is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">LOGBURST=</emphasis>[<emphasis>burst</emphasis>]</term>
<listitem>
<para></para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">LOGRATE=</emphasis>[<emphasis>rate</emphasis>/{<emphasis
role="bold">minute</emphasis>|<emphasis
role="bold">second</emphasis>}]</term>
<listitem>
<para>These parameters set the match rate and initial burst size for
logged packets. Please see the iptables man page for a description
of the behavior of these parameters (the iptables option --limit is
set by LOGRATE and --limit-burst is set by LOGBURST). If both
parameters are set empty, no rate-limiting will occur.</para>
<para>Example:</para>
<programlisting> LOGRATE=10/minute
LOGBURST=5</programlisting>
<para>For each logging rule, the first time the rule is reached, the
packet will be logged; in fact, since the burst is 5, the first five
packets will be logged. After this, it will be 6 seconds (1 minute
divided by the rate of 10) before a message will be logged from the
rule, regardless of how many packets reach it. Also, every 6 seconds
which passes without matching a packet, one of the bursts will be
regained; if no packets hit the rule for 30 seconds, the burst will
be fully recharged; back where we started.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">MACLIST_DISPOSITION=</emphasis>[<emphasis
role="bold">ACCEPT</emphasis>|<emphasis
role="bold">DROP</emphasis>|<emphasis
role="bold">REJECT</emphasis>]</term>
<listitem>
<para>Determines the disposition of connections requests that fail
MAC Verification and must have the value ACCEPT (accept the
connection request anyway), REJECT (reject the connection request)
or DROP (ignore the connection request). If not set or if set to the
empty value (e.g., MACLIST_DISPOSITION="") then
MACLIST_DISPOSITION=REJECT is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">MACLIST_LOG_LEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>
<listitem>
<para>Determines the syslog level for logging connection requests
that fail MAC Verification. The value must be a valid syslogd log
level. If you don't want to log these connection requests, set to
the empty value (e.g., MACLIST_LOG_LEVEL="").</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">MACLIST_TABLE=</emphasis>[<emphasis
role="bold">filter</emphasis>|<emphasis
role="bold">mangle</emphasis>]</term>
<listitem>
<para>Normally, MAC verification occurs in the filter table (INPUT
and FORWARD) chains. When forwarding a packet from an interface with
MAC verification to a bridge interface, that doesn't work.</para>
<para>This problem can be worked around by setting
MACLIST_TABLE=mangle which will cause Mac verification to occur out
of the PREROUTING chain. Because REJECT isn't available in that
environment, you may not specify MACLIST_DISPOSITION=REJECT with
MACLIST_TABLE=mangle.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">MACLIST_TTL=[</emphasis><emphasis>number</emphasis>]</term>
<listitem>
<para>The performance of configurations with a large numbers of
entries in /etc/shorewall/maclist can be improved by setting the
MACLIST_TTL variable in shorewall.conf(5).</para>
<para>If your iptables and kernel support the "Recent Match" (see
the output of "shorewall check" near the top), you can cache the
results of a 'maclist' file lookup and thus reduce the overhead
associated with MAC Verification.</para>
<para>When a new connection arrives from a 'maclist' interface, the
packet passes through then list of entries for that interface in
shorewall-maclist(5). If there is a match then the source IP address
is added to the 'Recent' set for that interface. Subsequent
connection attempts from that IP address occurring within
$MACLIST_TTL seconds will be accepted without having to scan all of
the entries. After $MACLIST_TTL from the first accepted connection
request from an IP address, the next connection request from that IP
address will be checked against the entire list.</para>
<para>If MACLIST_TTL is not specified or is specified as empty (e.g,
MACLIST_TTL="" or is specified as zero then 'maclist' lookups will
not be cached).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">MAPOLDACTIONS=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>Previously, Shorewall included a large number of standard
actions (AllowPing, AllowFTP, ...). These have been replaced with
parameterized macros. For compatibility, Shorewall can map the old
names into invocations of the new macros if you set
MAPOLDACTIONS=Yes. If this option is not set or is set to the empty
value (MAPOLDACTIONS="") then MAPOLDACTIONS=Yes is assumed</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">MARK_IN_FORWARD_CHAIN=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>If your kernel has a FORWARD chain in the mangle table, you
may set MARK_IN_FORWARD_CHAIN=Yes to cause the marking specified in
the tcrules file to occur in that chain rather than in the
PREROUTING chain. This permits you to mark inbound traffic based on
its destination address when SNAT or Masquerading are in use. To
determine if your kernel has a FORWARD chain in the mangle table,
use the <emphasis role="bold">/sbin/shorewall show mangle</emphasis>
command; if a FORWARD chain is displayed then your kernel will
support this option. If this option is not specified or if it is
given the empty value (e.g., MARK_IN_FORWARD_CHAIN="") then
MARK_IN_FORWARD_CHAIN=No is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">MODULE_SUFFIX=</emphasis>[<emphasis
role="bold">"</emphasis><emphasis>extension</emphasis> ...<emphasis
role="bold">"</emphasis>]</term>
<listitem>
<para>The value of this option determines the possible file
extensions of kernel modules. The default value is "o gz ko
o.gz".</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">MODULESDIR=</emphasis>[<emphasis>pathname</emphasis>[<emphasis
role="bold">:</emphasis><emphasis>pathname</emphasis>]...]</term>
<listitem>
<para>This parameter specifies the directory/directories where your
kernel netfilter modules may be found. If you leave the variable
empty, Shorewall will supply the value "/lib/modules/`uname
-r`/kernel/net/ipv4/netfilter" in versions of Shorewall prior to
3.2.4 and "/lib/modules/`uname
-r`/kernel/net/ipv4/netfilter:/lib/modules/`uname
-r`/kernel/net/ipv4/netfilter" in later versions.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">MUTEX_TIMEOUT=</emphasis>[<emphasis>seconds</emphasis>]</term>
<listitem>
<para>The value of this variable determines the number of seconds
that programs will wait for exclusive access to the Shorewall lock
file. After the number of seconds corresponding to the value of this
variable, programs will assume that the last program to hold the
lock died without releasing the lock.</para>
<para>If not set or set to the empty value, a value of 60 (60
seconds) is assumed.</para>
<para>An appropriate value for this parameter would be twice the
length of time that it takes your firewall system to process a
<emphasis role="bold">shorewall restart</emphasis> command.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">OPTIMIZE=</emphasis>[<emphasis
role="bold">0</emphasis>|<emphasis role="bold">1</emphasis>]</term>
<listitem>
<para>Traditionally, Shorewall has created rules for the complete
matrix of Networks defined by the zones, interfaces and hosts files.
Any traffic that didn't correspond to an element of that matrix was
rejected in one of the built-in changes. When the matrix is sparse,
this results in lots of largely useless rules.</para>
<para>These extra rules can be eliminated by setting
OPTIMIZE=1.</para>
<para>The OPTIMIZE setting also controls the suppression of
redundant wildcard rules (those specifying "all" in the SOURCE or
DEST column). A wildcard rule is considered to be redundant when it
has the same ACTION and Log Level as the applicable policy.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">PATH=</emphasis><emphasis>pathname</emphasis>[<emphasis
role="bold">:</emphasis><emphasis>pathname</emphasis>]...</term>
<listitem>
<para>Determines the order in which Shorewall searches directories
for executable files.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">PKTTYPE=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>Normally Shorewall attempts to use the iptables packet type
match extension to determine broadcast and multicast packets.</para>
<orderedlist>
<listitem>
<para>This can cause a message to appear during shorewall start
(modprobe: cant locate module ipt_pkttype).</para>
</listitem>
<listitem>
<para>Some users have found problems with the packet match
extension with the result that their firewall log is flooded
with messages relating to broadcast packets.</para>
</listitem>
</orderedlist>
<para>If you are experiencing either of these problems, setting
PKTTYPE=No will prevent Shorewall from trying to use the packet type
match extension and to use IP address matching to determine which
packets are broadcasts or multicasts.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">RESTOREFILE=</emphasis><emphasis>filename</emphasis></term>
<listitem>
<para>Specifies the simple name of a file in /var/lib/shorewall to
be used as the default restore script in the <emphasis
role="bold">shorewall save</emphasis>, <emphasis
role="bold">shorewall restore</emphasis>, <emphasis
role="bold">shorewall forget </emphasis>and <emphasis
role="bold">shorewall -f start</emphasis> commands.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">RETAIN_ALIASES=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>During <emphasis role="bold">shorewall star</emphasis>t, IP
addresses to be added as a consequence of ADD_IP_ALIASES=Yes and
ADD_SNAT_ALIASES=Yes are quietly deleted when shorewall-nat(5) and
shorewall-masq(5) are processed then are re-added later. This is
done to help ensure that the addresses can be added with the
specified labels but can have the undesirable side effect of causing
routes to be quietly deleted. When RETAIN_ALIASES is set to Yes,
existing addresses will not be deleted. Regardless of the setting of
RETAIN_ALIASES, addresses added during <emphasis
role="bold">shorewall start</emphasis> are still deleted at a
subsequent <emphasis role="bold">shorewall stop</emphasis> or
<emphasis role="bold">shorewall restart</emphasis>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">RFC1918_LOG_LEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>
<listitem>
<para>This parameter determines the level at which packets logged
under the <emphasis role="bold">norfc1918</emphasis> mechanism are
logged. The value must be a valid syslog level and if no level is
given, then info is assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">RFC1918_STRICT=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>Traditionally, the RETURN target in the 'rfc1918' file has
caused norfc1918 processing to cease for a packet if the packet's
source IP address matches the rule. Thus, if you have this entry in
/etc/shorewall/rfc1918:</para>
<programlisting> #SUBNETS TARGET
192.168.1.0/24 RETURN</programlisting>
<para>then traffic from 192.168.1.4 to 10.0.3.9 will be accepted
even though you also have:</para>
<programlisting> #SUBNETS TARGET
10.0.0.0/8 logdrop</programlisting>
<para>Setting RFC1918_STRICT=Yes in shorewall.conf will cause such
traffic to be logged and dropped since while the packet's source
matches the RETURN rule, the packet's destination matches the
'logdrop' rule.</para>
<para>If not specified or specified as empty (e.g.,
RFC1918_STRICT="") then RFC1918_STRICT=No is assumed.</para>
<warning>
<para>RFC1918_STRICT=Yes requires that your kernel and iptables
support 'Connection Tracking' match.</para>
</warning>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ROUTE_FILTER=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>
<listitem>
<para>If this parameter is given the value <emphasis
role="bold">Yes</emphasis> or <emphasis role="bold">yes</emphasis>
then route filtering (anti-spoofing) is enabled on all network
interfaces which are brought up while Shorewall is in the started
state. The default value is <emphasis
role="bold">no</emphasis>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">SAVE_IPSETS=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>If SAVE_IPSETS=Yes, then the current contents of your ipsets
will be saved by the <emphasis role="bold">shorewall save</emphasis>
command. Regardless of the setting of SAVE_IPSETS, if saved ipset
contents are available then they will be restored by <emphasis
role="bold">shorewall restore</emphasis>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">SHOREWALL_SHELL=</emphasis>[<emphasis>pathname</emphasis>]</term>
<listitem>
<para>This option is used to specify the shell program to be used to
run the Shorewall compiler and to interpret the compiled script. If
not specified or specified as a null value, /bin/sh is assumed.
Using a light-weight shell such as ash or dash can significantly
improve performance.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">SMURF_LOG_LEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>
<listitem>
<para>Specifies the logging level for smurf packets (see the
nosmurfs option in /etc/shorewall/interfaces). If set to the empty
value ( SMURF_LOG_LEVEL="" ) then smurfs are not logged.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">STARTUP_ENABLED=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>Determines if Shorewall is allowed to start. As released from
shorewall.net, this option is set to <emphasis
role="bold">No</emphasis>. When set to <emphasis
role="bold">Yes</emphasis> or <emphasis role="bold">yes</emphasis>,
Shorewall may be started. Used as a guard against Shorewall being
accidentally started before it has been configured.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">SUBSYSLOCK=</emphasis>[<emphasis>pathname</emphasis>]</term>
<listitem>
<para>This parameter should be set to the name of a file that the
firewall should create if it starts successfully and remove when it
stops. Creating and removing this file allows Shorewall to work with
your distribution's initscripts. For RedHat, this should be set to
/var/lock/subsys/shorewall. For Debian, the value is
/var/state/shorewall and in LEAF it is /var/run/shorwall.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">TC_ENABLED=</emphasis>[<emphasis
role="bold">Yes</emphasis>|<emphasis
role="bold">No</emphasis>|<emphasis
role="bold">Internal</emphasis>]</term>
<listitem>
<para>If you say <emphasis role="bold">Yes</emphasis> or <emphasis
role="bold">yes</emphasis> here, Shorewall will use a script that
you supply to configure traffic shaping. The script must be named
'tcstart' and must be placed in a directory on your
CONFIG_PATH.</para>
<para>If you say <emphasis role="bold">No</emphasis> or <emphasis
role="bold">no</emphasis> then traffic shaping is not
enabled.</para>
<para>If you set TC_ENABLED=Internal or internal or leave the option
empty then Shorewall will use its builtin traffic shaper
(tc4shorewall written by Arne Bernin.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">TC_EXPERT=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>Normally, Shorewall tries to protect users from themselves by
preventing PREROUTING and OUTPUT tcrules from being applied to
packets that have been marked by the 'track' option in
shorewall-providers(5).</para>
<para>If you know what you are doing, you can set TC_EXPERT=Yes and
Shorewall will not include these cautionary checks.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">TCP_FLAGS_DISPOSITION=</emphasis>[<emphasis
role="bold">ACCEPT</emphasis>|<emphasis
role="bold">DROP</emphasis>|<emphasis
role="bold">REJECT</emphasis>]</term>
<listitem>
<para>Determines the disposition of TCP packets that fail the checks
enabled by the <emphasis role="bold">tcpflags</emphasis> interface
option (see shorewall-interfaces(5)) and must have a value of ACCEPT
(accept the packet), REJECT (send an RST response) or DROP (ignore
the packet). If not set or if set to the empty value (e.g.,
TCP_FLAGS_DISPOSITION="") then TCP_FLAGS_DISPOSITION=DROP is
assumed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">TCP_FLAGS_LOG_LEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>
<listitem>
<para>Determines the syslog level for logging packets that fail the
checks enabled by the tcpflags interface option. The value must be a
valid syslogd log level. If you don't want to log these packets, set
to the empty value (e.g., TCP_FLAGS_LOG_LEVEL="").</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">USE_ACTIONS=</emphasis>{<emphasis
role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>
<listitem>
<para>While Shorewall Actions can be very useful, they also require
a sizable amount of code to implement. By setting USE_ACTIONS=No,
embedded Shorewall installations can omit the large library
/usr/share/shorewall/lib.actions.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">VERBOSITY=</emphasis>[<emphasis>number</emphasis>]</term>
<listitem>
<para>Shorewall has traditionally been very noisy (produced lots of
output). You may set the default level of verbosity using the
VERBOSITY OPTION.</para>
<para>Values are:</para>
<simplelist>
<member>0 — Silent. You may make it more verbose using the -v
option</member>
<member>1 — Major progress messages displayed</member>
<member>2 — All progress messages displayed (old default
behavior)</member>
</simplelist>
<para>If not specified, then 2 is assumed.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>FILES</title>
<para>/etc/shorewall/shorewall.conf</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-rules(5),
shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)</para>
</refsect1>
</refentry>