Provided by: shorewall6_4.2.10-1_all bug


       shorewall6.conf - Shorewall6 global configuration file




       This file sets options that apply to Shorewall6 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 Shorewall6 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 Shorewall6 logging, a level of 6 (info) is appropriate.
       Shorewall6 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 NFLOG target support, you may also
       specify a log level of NFLOG (must be all caps). Rather than log its
       messages to syslogd, Shorewall6 will direct netfilter to log the
       messages via the 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 Shorewall6 message to their own log file

       The following options may be set in shorewall6.conf.





           In earlier Shorewall6 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
                           (Shorewall6-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 shorewall6-policy[1](5).

           The value of this variable affects Shorewall6´s stopped state. When
           ADMINISABSENTMINDED=No, only traffic to/from those addresses listed
           in shorewall6-routestopped[2](5) is accepted when Shorewall6 is
           stopped. When ADMINISABSENTMINDED=Yes, in addition to traffic
           to/from addresses in shorewall6-routestopped[2](5), connections
           that were active when Shorewall6 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.

           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

           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.

           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 Shorewall6 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/shorewall6/tcstart file. That
           way, your traffic shaping rules can still use the “fwmark”
           classifier based on packet marking defined in
           shorewall6-tcrules[3](5). If not specified, CLEAR_TC=No is assumed.

           If you also run Shorewall and if you have TC_ENABLED=Internal in
           your shorewall-conf[4](5), then you will want CLEAR_TC=No in this

           Specifies where configuration files other than shorewall6.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 shorewall6.conf:

           ·   If the command is "try" or a "<configuration directory>" was
               specified in the command (e.g., shorewall6 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/shorewall6/configpath are used.
               As released from, that file sets the CONFIG_PATH
               to /etc/shorewall6:/usr/share/shorewall6:/usr/share/shorewall
               but your particular distribution may set it differently. See
               the output of shorewall6 show config for the default on your

               Note that the setting in /usr/share/shorewall6/configpath is
               always used to locate shorewall6.conf.

           If set to Yes (the default value), entries in the
           /etc/shorewall6/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.

           Causes Shorewall6 to not load the listed kernel modules.

           Normally, when the SOURCE or DEST columns in shorewall6-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
           Shorewall6 log messages generated as a result of the policy. If
           EXPAND_POLICIES=Yes, then Shorewall6 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 Shorewall6
           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, Shorewall6 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 shorewall6-rules[5](5).

           FASTACCEPT=Yes is incompatible with BLACKLISTNEWONLY=No.

           You may 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. Shorewall6 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 shorewall6-zones[6](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
           shorewall6-nesting[7](5). With IMPLICIT_CONTINUE=Yes, that happens

           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 Shorewall6 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
               Shorewall6 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 parameter names the ip6tables executable to be used by
           Shorewall6. If not specified or if specified as a null value, then
           the ip6tables executable located using the PATH option is used.

           Regardless of how the ip6tables utility is located (specified via
           IP6TABLES= or located via PATH), Shorewall6 uses the
           ip6tables-restore and ip6tables-save utilities from that same

           When set to Yes, this option prevents scripts generated by
           Shorewall6 from altering the /etc/iproute2/rt_tables database when
           there are entries in /etc/shorewall6/providers. If you set this
           option to Yes while Shorewall6 (Shorewall6-lite) is running, you
           should remove the file /var/lib/shorewall6/rt_tables
           (/var/lib/shorewall6-lite/rt_tables) before your next stop,
           refresh, restore on restart command.

           The default is KEEP_RT_TABLES=No.

           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 Shorewall6 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/shorewall6 program where to look for
           Shorewall6 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
           Shorewall6 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
           “Shorewall6:%s:%s:” is assumed.


           These parameters set the match rate and initial burst size for
           logged packets. Please see ip6tables(8) for a description of the
           behavior of these parameters (the ip6tables 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.

           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/shorewall6 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, Shorewall6 will supply the value "/lib/modules/‘uname
           -r‘/kernel/net/ipv4/netfilter" in versions of Shorewall6 prior to
           3.2.4 and "/lib/modules/‘uname
           -r‘/kernel/net/ipv4/netfilter" in later versions.

           The value of this variable determines the number of seconds that
           programs will wait for exclusive access to the Shorewall6 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 shorewall6
           restart command.

           Traditionally, Shorewall6 has created rules for the complete matrix
           of host groups defined by the zones, interfaces and hosts files[8].
           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 Shorewall6 searches directories for
           executable files.


           Eariler generations of Shorewall6 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 shorewall6.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

           Specifies the simple name of a file in /var/lib/shorewall6 to be
           used as the default restore script in the shorewall6 save,
           shorewall6 restore, shorewall6 forget and shorewall6 -f start

           If SAVE_IPSETS=Yes, then the current contents of your ipsets will
           be saved by the shorewall6 save command. Regardless of the setting
           of SAVE_IPSETS, if saved ipset contents are available then they
           will be restored by shorewall6 restore.

           This option is used to specify the shell program to be used 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.

           Specifies the logging level for smurf packets (see the nosmurfs
           option in shorewall6-interfaces[9](5)). If set to the empty value (
           SMURF_LOG_LEVEL="" ) then smurfs are not logged.

           Determines if Shorewall6 is allowed to start. As released from
 , this option is set to No. When set to Yes or yes,
           Shorewall6 may be started. Used as a guard against Shorewall6 being
           accidentally started before it has been configured.

           If specified, determines where Shorewall6 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 Shorewall6 to work
           with your distribution´s initscripts. For RedHat, this should be
           set to /var/lock/subsys/shorewall6. For Debian, the value is
           /var/lock/shorewall6 and in LEAF it is /var/run/shorwall.

           If you say Yes or yes here, Shorewall6 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 Shorewall6 will use its builtin traffic shaper
           (tc4shorewall6 written by Arne Bernin.

           If you also run Shorewall and if you have TC_ENABLED=Internal in
           your shorewall-conf[4](5), then you will want TC_ENABLED=No in this

           Normally, Shorewall6 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
           Shorewall6 will not include these cautionary checks.

           Determines the disposition of TCP packets that fail the checks
           enabled by the tcpflags interface option (see
           shorewall6-interfaces[9](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="").

           Shorewall6 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 Shorewall6-3.2.0
                           behavior) If not specified, then 2 is assumed.




       shorewall6(8), shorewall6-accounting(5), shorewall6-actions(5),
       shorewall6-blacklist(5), shorewall6-hosts(5), shorewall6-interfaces(5),
       shorewall6-ipsec(5), shorewall6-maclist(5), shorewall6-masq(5),
       shorewall6-nat(5), shorewall6-netmap(5), shorewall6-params(5),
       shorewall6-policy(5), shorewall6-providers(5), shorewall6-proxyarp(5),
       shorewall6-route_rules(5), shorewall6-routestopped(5),
       shorewall6-rules(5), shorewall6-tcclasses(5), shorewall6-tcdevices(5),
       shorewall6-tcrules(5), shorewall6-tos(5), shorewall6-tunnels(5),


        1. shorewall6-policy

        2. shorewall6-routestopped

        3. shorewall6-tcrules

        4. shorewall-conf

        5. shorewall6-rules

        6. shorewall6-zones

        7. shorewall6-nesting

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

        9. shorewall6-interfaces

       10. shorewall6-providers

                                  06/18/2009                SHOREWALL6.CONF(5)