Provided by: shorewall-common_4.2.10-1_all bug


       shorewall.conf - Shorewall global configuration file




       This file sets options that apply to Shorewall as a whole.

       The file consists of Shell comments (lines beginning with ´#´), blank
       lines and assignment statements (variable=value).


       Many options have as their value a log-level. 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.

       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.

       Valid levels are:

                  7       debug
                  6       info
                  5       notice
                  4       warning
                  3       err
                  2       crit
                  1       alert
                  0       emerg

       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.

       If you have built your kernel with ULOG and/or NFLOG target support,
       you may also specify a log level of ULOG and/or NFLOG (must be all
       caps). Rather than log its messages to syslogd, Shorewall will direct
       netfilter to log the messages via the ULOG or NFLOG 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 and can be
       configured to log all Shorewall message to their own log file

       The following options may be set in shorewall.conf.





       NFQUEUE_DEFAULT={action|macro|none} (Shorewall-perl 4.0.3 and later)
           In earlier Shorewall versions, a "default action" for DROP and
           REJECT policies was specified in the file

           To allow for default rules to be applied when USE_ACTIONS=No, the
           NFQUEUE_DEFAULT options have been added.

           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 three are similar for ACCEPT, QUEUE and NFQUEUE

           The value applied to these may be:

               a) The name of an

               b) The name of a macro
                           (Shorewall-shell only)

               c) None or none The default values are:





               NFQUEUE_DEFAULT="None" 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

               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[1](5).

           This parameter determines whether Shorewall automatically adds the
           external address(es) in shorewall-nat[2](5). If the variable is set
           to Yes or yes then Shorewall automatically adds these aliases. If
           it is set to No or no, you must add these aliases yourself using
           your distribution´s network configuration tools.

           If this variable is not set or is given an empty value
           (ADD_IP_ALIASES="") then ADD_IP_ALIASES=Yes is assumed.

           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.

           This parameter determines whether Shorewall automatically adds the
           SNAT ADDRESS in shorewall-masq[3](5). If the variable is set to Yes
           or yes then Shorewall automatically adds these addresses. If it is
           set to No or no, you must add these addresses yourself using your
           distribution´s network configuration tools.

           If this variable is not set or is given an empty value
           (ADD_SNAT_ALIASES="") then ADD_SNAT_ALIASES=No is assumed.

           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.

           The value of this variable affects Shorewall´s stopped state. When
           ADMINISABSENTMINDED=No, only traffic to/from those addresses listed
           in shorewall-routestopped[4](5) is accepted when Shorewall is
           stopped. When ADMINISABSENTMINDED=Yes, in addition to traffic
           to/from addresses in shorewall-routestopped[4](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.

           Added in Shorewall-perl 4.1.5. If set, if there is not a current
           comment when a macro is invoked, the behavior is as if the first
           line of the macro file was "COMMENT <macro name>". The AUTO_COMMENT
           option has a default value of ´Yes´.

           Setting this option to ´Yes´ allows you to include arbitrarily long
           destination port lists in all configuration files.

           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

           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

           When set to Yes or yes, blacklists are only consulted for new
           connections. When set to No or no, blacklists are consulted for
           every packet (will slow down your firewall noticably if you have
           large blacklists). If the BLACKLISTNEWONLY option is not set or is
           set to the empty value then BLACKLISTNEWONLY=No is assumed.

           BLACKLISTNEWONLY=No is incompatible with FASTACCEPT=Yes.

           When set to Yes or yes, enables Shorewall Bridging support.

           BRIDGING=Yes may not work properly with Linux kernel 2.6.20 or
           later and is not supported by Shorewall-perl.

           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 Yes or yes, the feature is
           enabled. If left blank or set to No or no, the feature is not

           Important: This option requires CONFIG_IP_NF_TARGET_TCPMSS in your

           You may also set CLAMPMSS to a numeric value (e.g., CLAMPMSS=1400).
           This will set the MSS field in TCP SYN packets going through the
           firewall to the value that you specify.

           If this option is set to No 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](5). If not specified, CLEAR_TC=Yes is assumed.

           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:

           ·   If the command is "try" or a "<configuration directory>" was
               specified in the command (e.g., shorewall check ./gateway) then
               the directory given in the command is searched first.

           ·   Next, each directory in the CONFIG_PATH setting is searched in

               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, 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.

               Note that the setting in /usr/share/shorewall/configpath is
               always used to locate shorewall.conf.

           Users with a large static black list (shorewall-blacklist[6](5))
           may want to set the DELAYBLACKLISTLOAD option to Yes. When
           DELAYBLACKLISTLOAD=Yes, Shorewall will enable new connections
           before loading the blacklist rules. While this may allow
           connections from blacklisted hosts to slip by during construction
           of the blacklist, it can substantially reduce the time that all new
           connections are disabled during shorewall [re]start.

           DELAYBLACKLISTLOAD=Yes is not supported by Shorewall-perl.

           Added in Shorewall 4.0.4. If set to Yes (the default value),
           entries in the /etc/shorewall/route_stopped files cause an ´ip rule
           del´ command to be generated in addition to an ´ip rule add´
           command. Setting this option to No, causes the ´ip rule del´
           command to be omitted.

           If set to Yes or yes, 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 No or
           no, Shorewall will not detect this address and any destination IP
           address will match the DNAT rule. If not specified or empty,
           “DETECT_DNAT_IPADDRS=Yes” is assumed.

           If set to Yes or yes, IPv6 traffic to, from and through the
           firewall system is disabled. If set to No or no, Shorewall will
           take no action with respect to allowing or disallowing IPv6
           traffic. If not specified or empty, “DISABLE_IPV6=No” is assumed.

           Added in Shorewall-4.0.6. Causes Shorewall to not load the listed

           When set to Yes or yes, enables dynamic zones. DYNAMIC_ZONES=Yes is
           not allowed in configurations that will run under Shorewall Lite.

           DYNAMIC_ZONES=Yes is not supported by Shorewall-perl 4.2.0 and

           Normally, when the SOURCE or DEST columns in shorewall-policy(5)
           contains ´all´, a single policy chain is created and the policy is
           enforced in that chain. For example, if the policy entry is

               #SOURCE DEST POLICY LOG
               #                   LEVEL
               net     all  DROP   info

           then the chain name is ´net2all´ which is also the chain named in
           Shorewall log messages generated as a result of the policy. If
           EXPAND_POLICIES=Yes, then Shorewall-perl will create a separate
           chain for each pair of zones covered by the policy. This makes the
           resulting log messages easier to interpret since the chain in the
           messages will have a name of the form ´a2b´ where ´a´ is the SOURCE
           zone and ´b´ is the DEST zone.

           It is quite difficult to code a ´params´ file that assigns other
           than constant values such that it works correctly with Shorewall
           Lite. The EXPORTPARAMS option works around this problem. When
           EXPORTPARAMS=No, the ´params´ file is not copied to the compiler

           With EXPORTPARAMS=No, if you need to set environmental variables on
           the firewall system for use by your extension scripts, then do so
           in the init extension script.

           The default is EXPORTPARAMS=Yes

           Normally, Shorewall defers 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.

           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[7](5).

           FASTACCEPT=Yes is incompatible with BLACKLISTNEWONLY=No.

           Prior to version 3.2.0, it was not possible to use connection
           marking in shorewall-tcrules[5](5) if you have a multi-ISP
           configuration that uses the track option.

           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.

           When you do this:

            1.  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).

            2.  You may only set those mark values in the PREROUTING chain.

            3.  Marks used for traffic shaping must still be in the range of
               1-255 and may still not be set in the PREROUTING chain.

            4.  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.

           When this option is set to Yes, it causes subzones to be treated
           differently with respect to policies.

           Subzones are defined by following their name with ":" and a list of
           parent zones (in shorewall-zones[8](5)). 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; see shorewall-nesting[9](5).
           With IMPLICIT_CONTINUE=Yes, that happens automatically.

           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).

           This parameter determines whether Shorewall enables or disables
           IPV4 Packet Forwarding (/proc/sys/net/ipv4/ip_forward). Possible
           values are:

           On or on
               packet forwarding will be enabled.

           Off or off
               packet forwarding will be disabled.

           Keep or keep
               Shorewall will neither enable nor disable packet forwarding.

           If this variable is not set or is given an empty value
           (IP_FORWARD="") then IP_FORWARD=On is assumed.

           This should be set to zones for all new Shorewall installations.
           IPSECFILE=ipsec is only used for compatibility with
           pre-Shorewall-3.0 configurations.

           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.

           Regardless of how the IPTABLES utility is located (specified via
           IPTABLES= or located via PATH), Shorewall uses the iptables-restore
           and iptables-save utilities from that same directory.

           Added in Shorewall 4.0.3. When set to Yes, this option prevents
           scripts generated by Shorewall-perl from altering the
           /etc/iproute2/rt_tables database when there are entries in
           /etc/shorewall/providers. If you set this option to Yes while
           Shorewall (Shorewall-lite) is running, you should remove the file
           /var/lib/shorewall/rt_tables (/var/lib/shorewall-lite/rt_tables)
           before your next stop, refresh, restore on restart command.

           The default is KEEP_RT_TABLES=No.

           If set to Yes or yes, sets /proc/sys/net/ipv4/conf/*/log_martians
           to 1 with the exception of /proc/sys/net/ipv4/conf/all/log_martians
           which is set to 0. In Shorewall versions prior to 4.1.5, the
           default is No which sets both of the above to zero. In Shorewall
           4.1.5, the default value was chaned to Yes which sets both of the
           above to one. If you do not enable martian logging for all
           interfaces, you may still enable it for individual interfaces using
           the logmartians interface option in shorewall-interfaces[10](5).

           The value Keep causes Shorewall to ignore the option. If the option
           is set to Yes, then martians are logged on all interfaces. If the
           option is set to No, then martian logging is disabled on all
           interfaces except those specified in shorewall-interfaces[10](5).

           This option controls the amount of information logged to the file
           specified in the STARTUP_LOG option.

           Values are:

               -1 - Logging is disabled

               0 - Silent. Only error messages are logged.

               1 - Major progress messages logged.

               2 - All progress messages logged If not specified, then -1 is

           This option is intended for use as a debugging aid. When set to a
           log level, this option causes Shorewall to generate a logging rule
           as the first rule in each builtin chain.

           ·   The table name is used as the chain name in the log prefix.

           ·   The chain name is used as the target in the log prefix.

                For example, using the default LOGFORMAT, the log prefix for
               logging from the nat table´s PREROUTING chain is:


           To help insure that all packets in the NEW state are logged, rate
           limiting (LOGBURST and LOGRATE) should be disabled when using
           LOGALLNEW. 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.

           Do not use this option if the resulting log messages will be sent
           to another system.

           This parameter tells the /sbin/shorewall program where to look for
           Shorewall messages when processing the dump, logwatch, show log,
           and hits commands. If not assigned or if assigned an empty value,
           /var/log/messages is assumed.

           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:

                   LOGFORMAT="fp=%s:%d a=%s "
           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.


           These parameters set the match rate and initial burst size for
           logged packets. Please see iptables(8) 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.


           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.

           Using the default LOGFORMAT, chain names may not exceed 11
           characters or truncation of the log prefix may occur. Longer chain
           names may be used with log tags if you set LOGTAGONLY=Yes. With
           LOGTAGONLY=Yes, if a log tag is specified then the tag is included
           in the log prefix in place of the chain name.

           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.

           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="").

           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.

           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.

           The performance of configurations with a large numbers of entries
           in shorewall-maclist[11](5) can be improved by setting the
           MACLIST_TTL variable in shorewall.conf[12](5).

           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.

           When a new connection arrives from a ´maclist´ interface, the
           packet passes through then list of entries for that interface in
           shorewall-maclist[11](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.

           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).

           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.

           MAPOLDACTIONS=Yes is not supported by Shorewall-perl. With
           Shorewall-perl, if MAPOLDACTIONS is not set or is set to the ampty
           value then MAPOLDACTIONS=No is assumed.

           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 DNAT is in use. To determine if your
           kernel has a FORWARD chain in the mangle table, use the
           /sbin/shorewall show mangle 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.

       MODULE_SUFFIX=["extension ..."]
           The value of this option determines the possible file extensions of
           kernel modules. The default value is "o gz ko o.gz".

           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" in later versions.

           This option will normally be set to ´No´ (the default). It should
           be set to ´Yes´ under the following circumstances:

            1.  You have an interface that has parallel zones defined via

            2.  You want to forward multicast packets to two or more of those
               parallel zones.

               In such cases, you will configure a destonly network on each
               zone receiving multicasts.

               The MULTICAST option is only recognized by Shorewall-perl and
               is ignored by Shorewall-shell.

           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.

           If not set or set to the empty value, a value of 60 (60 seconds) is

           An appropriate value for this parameter would be twice the length
           of time that it takes your firewall system to process a shorewall
           restart command.

           Traditionally, Shorewall has created rules for the complete matrix
           of host groups defined by the zones, interfaces and hosts
           files[13]. Any traffic that didn´t correspond to an element of that
           matrix was rejected in one of the built-in chains. When the matrix
           is sparse, this results in lots of largely useless rules.

           These extra rules can be eliminated by setting OPTIMIZE=1.

           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.

           Determines the order in which Shorewall searches directories for
           executable files.

           Normally Shorewall attempts to use the iptables packet type match
           extension to determine broadcast and multicast packets.

            1.  This can cause a message to appear during shorewall start
               (modprobe: cant locate module ipt_pkttype).

            2.  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.

                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.


           Eariler generations of Shorewall Lite required that remote root
           login via ssh be enabled in order to use the load and reload
           commands. Beginning with release 3.9.5, you may define an
           alternative means for accessing the remote firewall system. In that
           release, two new options were added to shorewall.conf:.IP "" 4

               RCP_COMMAND The default values for these are as follows:.IP ""
               4 RSH_COMMAND: ssh ${root}@${system} ${command}

               RCP_COMMAND: scp ${files}
                             ${root}@${system}:${destination} Shell variables
               that will be set when the commands are envoked are as
               follows:.IP "" 4 root - root user. Normally
                             root but may be overridden using the ´-r´

               system - The name/IP address
                             of the remote firewall system.

               command - For RSH_COMMAND,
                             the command to be executed on the firewall

               files - For RCP_COMMAND, a
                             space-separated list of files to be copied to the
                             firewall system.

               destination - The directory
                             on the remote system that the files are to be

           Added in Shorewall 4.2.6, this option determines whether to restore
           the default route saved when here are ´balance´ providers defined
           but all of them are down.

           The default is RESTORE_DEFAULT_ROUTE=Yes which preserves the
           pre-4.2.6 behavior.

           RESTORE_DEFAULT_ROUTE=No is appropriate when you don´t want a
           default route in the main table (USE_DEFAULT_RT=No) or in the
           default table (USE_DEFAULT_RT=Yes) when there are no balance
           providers available. In that case, RESTORE_DEFAULT_ROUTE=No will
           cause any default route in the relevant table to be deleted.

           Specifies the simple name of a file in /var/lib/shorewall to be
           used as the default restore script in the shorewall save, shorewall
           restore, shorewall forget and shorewall -f start commands.

           During shorewall start, IP addresses to be added as a consequence
           of ADD_IP_ALIASES=Yes and ADD_SNAT_ALIASES=Yes are quietly deleted
           when shorewall-nat[2](5) and shorewall-masq[3](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 shorewall start are still deleted at a subsequent
           shorewall stop or shorewall restart.

           This parameter determines the level at which packets logged under
           the norfc1918 mechanism are logged. The value must be a valid
           syslog level and if no level is given, then info is assumed.

           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

                   #SUBNETS                 TARGET
           then traffic from to will be accepted even
           though you also have:

                   #SUBNETS                 TARGET
           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.

           If not specified or specified as empty (e.g., RFC1918_STRICT="")
           then RFC1918_STRICT=No is assumed.

           RFC1918_STRICT=Yes requires that your kernel and iptables support
           ´Connection Tracking´ match.

           If this parameter is given the value Yes or yes 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 no.

           The value Keep is only allowed under Shorewall-perl. It causes
           Shorewall to ignore the option. If the option is set to Yes, then
           route filtering occurs on all interfaces. If the option is set to
           No, then route filtering is disabled on all interfaces except those
           specified in shorewall-interfaces[10](5).

           If SAVE_IPSETS=Yes, then the current contents of your ipsets will
           be saved by the shorewall save command. Regardless of the setting
           of SAVE_IPSETS, if saved ipset contents are available then they
           will be restored by shorewall restore.

           Specifies the compiler to use to generate firewall scripts when
           both compilers are installed. The value of this option can be
           either perl or shell. If both compilers are installed and
           SHOREWALL_SHELL is not set, then SHOREWALL_SHELL=shell is assumed.

           If you add ´SHOREWALL_COMPILER=perl´ to
           /etc/shorewall/shorewall.conf then by default, the Shorewall-perl
           compiler will be used on the system. If you add it to
           shorewall.conf in a separate directory (such as a Shorewall-lite
           export directory) then the Shorewall-perl compiler will only be
           used when you compile from that directory.

           If you only install one compiler, it is suggested that you do not
           set SHOREWALL_COMPILER.

           This setting may be overriden in those commands that invoke the
           compiler by using the -C command option (see shorewall[15](8)).

           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

           Specifies the logging level for smurf packets (see the nosmurfs
           option in shorewall-interfaces[10](5)). If set to the empty value (
           SMURF_LOG_LEVEL="" ) then smurfs are not logged.

           Determines if Shorewall is allowed to start. As released from
 , this option is set to No. When set to Yes or yes,
           Shorewall may be started. Used as a guard against Shorewall being
           accidentally started before it has been configured.

           If specified, determines where Shorewall will log the details of
           each start, restart and refresh command. Logging verbosity is
           determined by the setting of LOG_VERBOSITY above.

           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 and OpenSuSE, this
           should be set to /var/lock/subsys/shorewall. For Debian, the value
           is /var/lock/shorewall and in LEAF it is /var/run/shorwall.

           If you say Yes or yes 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.

           If you say No or no then traffic shaping is not enabled.

           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.

           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

           If you know what you are doing, you can set TC_EXPERT=Yes and
           Shorewall will not include these cautionary checks.

           Determines the disposition of TCP packets that fail the checks
           enabled by the tcpflags interface option (see
           shorewall-interfaces[10](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.,

           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="").

           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

           USE_ACTIONS=No is not supported by Shorewall-perl.

           When set to ´Yes´, this option causes the Shorewall multi-ISP
           feature to create a different set of routing rules which are
           resilient to changes in the main routing table. Such changes can
           occur for a number of reasons, VPNs going up and down being an
           example. The idea is to send packets through the main table prior
           to applying any of the Shorewall-generated routing rules. So
           changes to the main table will affect the routing of packets by

           When USE_DEFAULT_RT=Yes:

            1.  Both the DUPLICATE and the COPY columns in providers[16](5)
               file must remain empty (or contain "-").

            2.  The default route is added to the the ´default´ table rather
               than to the main table.

            3.  balance is assumed unless loose is specified.

            4.  Packets are sent through the main routing table by a rule with
               priority 999. In routing_rules[17](5), the range 1-998 may be
               used for inserting rules that bypass the main table.

            5.  All provider gateways must be specified explicitly in the
               GATEWAY column.  detect may not be specified..sp
               Beginning with Shorewall 4.2.6, detect may be specified for
               interfaces whose configuration is managed by dhcpcd. Shorewall
               will use dhcpcd´s database to find the interfaces´s gateway.

            6.  You should disable all default route management outside of
               Shorewall. If a default route is added to the main table while
               Shorewall is started, then all policy routing will stop working
               (except for those routing rules in the priority range 1-998).

               If USE_DEFAULT_RT is not set or if it is set to the empty
               string then USE_DEFAULT_RT=No is assumed.

           Shorewall has traditionally been very noisy (produced lots of
           output). You may set the default level of verbosity using the

           Values are:

               0 - Silent. You may make it more verbose using the -v

               1 - Major progress messages displayed

               2 - All progress messages displayed (pre Shorewall-3.2.0
                           behavior) If not specified, then 2 is assumed.




       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),


        1. shorewall-policy

        2. shorewall-nat

        3. shorewall-masq

        4. shorewall-routestopped

        5. shorewall-tcrules

        6. shorewall-blacklist

        7. shorewall-rules

        8. shorewall-zones

        9. shorewall-nesting

       10. shorewall-interfaces

       11. shorewall-maclist

       12. shorewall.conf

       13. the complete matrix of host groups defined by the zones, interfaces
           and hosts files

       14. shorewall-rfc1918

       15. shorewall

       16. shorewall-providers

       17. routing_rules

                                  06/18/2009                 SHOREWALL.CONF(5)