SHOREWALL6.CONF(5) [FIXME: manual] SHOREWALL6.CONF(5)
NAME
shorewall6.conf - Shorewall6 global configuration file
SYNOPSIS
/etc/shorewall6/shorewall6.conf
DESCRIPTION
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). If the value
contains shell metacharacters or white-space, then it must be enclosed in quotes. Example: LOG_LEVEL="NFLOG(1,0,1)".
OPTIONS
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
http://www.netfilter.org/projects/ulogd/index.html and can be configured to log all Shorewall6 message to their own log file
The following options may be set in shorewall6.conf.
ACCEPT_DEFAULT={action|none}
DROP_DEFAULT={action|none}
NFQUEUE_DEFAULT={action|none}
QUEUE_DEFAULT={action|none}
REJECT_DEFAULT={action|none}
To allow for default rules to be applied when USE_ACTIONS=No, the DROP_DEFAULT, REJECT_DEFAULT, ACCEPT_DEFAULT, QUEUE_DEFAULT and
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
policies.
The value applied to these may be:
a) The name of an
action.
b) The name of a macro
(Shorewall6-shell only)
c) None or none
The default values are:
DROP_DEFAULT="Drop"
REJECT_DEFAULT="Reject"
ACCEPT_DEFAULT="none"
QUEUE_DEFAULT="none"
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 macro.Reject.
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).
ACCOUNTING=[Yes|No]
Added in Shorewall 4.4.7. If set to Yes, Shorewall6 accounting is enabled (see shorewall6-accounting[2](5)). If not specified or set to
the empty value, ACCOUNTING=Yes is assumed.
ACCOUNTING_TABLE=[filter|mangle]
Added in Shorewall 4.4.20. This setting determines which Netfilter table the accounting rules are added in. By default,
ACCOUNTING_TABLE=filter is assumed. See also shorewall-accounting[3](5).
ADMINISABSENTMINDED=[Yes|No]
The value of this variable affects Shorewall6's stopped state. When ADMINISABSENTMINDED=No, only traffic to/from those addresses listed
in shorewall6-routestopped[4](5) is accepted when Shorewall6 is stopped. When ADMINISABSENTMINDED=Yes, in addition to traffic to/from
addresses in shorewall6-routestopped[4](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.
AUTO_COMMENT=[Yes|No]
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'.
AUTOMAKE=[Yes|No]
If set, the behavior of the start and restart commands is change; if no files in /etc/shorewall have been changed since the last
successful start or restart command, then the compilation step is skipped and the compiled script that executed the last start or
restart command is used. The default is AUTOMAKE=No.
The setting of the AUTOMAKE option is ignored if the start or restart command includes a directory name (e.g., shorewall6 restart
/etc/shorewall.new).
BLACKLIST_DISPOSITION=[DROP|A_DROP|REJECT|A_REJECT]
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. The BLACKLIST_DISPOSITION setting has no effect on entries in the BLACKLIST
section of shorewall6-rules[5] (5). It determines the disposition of packets sent to the blacklog target of shorewall6-blrules[6](5).
BLACKLIST_LOGLEVEL=[log-level]
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. The BLACKLIST_LOGLEVEL setting has no effect on entries in the BLACKLIST section of
shorewall6-rules[5] (5). It determines the log level of packets sent to the blacklog target of shorewall6-blrules[6](5).
BLACKLISTNEWONLY={Yes|No}
When set to Yes or yes, blacklists are only consulted for new connections. This includes entries in the shorewall-blrules[7] (5) file
and in the BLACKLIST section of shorewall6-rules[5] (5).
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.
Note
BLACKLISTNEWONLY=No is incompatible with FASTACCEPT=Yes.
CLAMPMSS=[Yes|No|value]
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 enabled.
Important: This option requires CONFIG_IP_NF_TARGET_TCPMSS in your kernel.
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.
CLEAR_TC=[Yes|No]
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[8](5). If
not specified, CLEAR_TC=No is assumed.
Warning
If you also run Shorewall and if you have TC_ENABLED=Internal in your shorewall-conf[9](5), then you will want CLEAR_TC=No in this
file.
COMPLETE=[Yes|No]
Added in Shorewall6 4.4.12. When you set this option to Yes, you are asserting that the configuration is complete so that your set of
zones encompasses any hosts that can send or receive traffic to/from/through the firewall. This causes Shorewall6 to omit the rules
that catch packets in which the source or destination IP address is outside of any of your zones. Default is No. It is recommended that
this option only be set to Yes if:
o You have defined an interface whose effective physical setting is '+'.
o That interface is assigned to a zone.
o You have no CONTINUE policies or rules.
CONFIG_PATH=[directory[:directory]...]
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:
o 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.
o Next, each directory in the CONFIG_PATH setting is searched in sequence.
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 shorewall.net, 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 system.
Note that the setting in /usr/share/shorewall6/configpath is always used to locate shorewall6.conf.
DELETE_THEN_ADD={Yes|No}
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.
DONT_LOAD=[module[,module]...]
Causes Shorewall6 to not load the listed kernel modules.
DYNAMIC_BLACKLIST={Yes|No}
Added in Shorewall 4.4.7. When set to No or no, dynamic blacklisting using the shorewall6 drop, shorewall6 reject, shorewall6 logdrop
and shorewall6 logreject is disabled. Default is Yes.
EXPAND_POLICIES={Yes|No}
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 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.
EXPORTMODULES=[Yes|No]
Added in Shorewall 4.4.17. When set to Yes when compiling for use by Shorewall6 Lite (shorewall6 load, shorewall6 reload or shorewall6
export commands), the compiler will copy the modules or helpers file from the administrative system into the script. When set to No or
not specified, the compiler will not copy the modules or helpers file from /usr/share/shorewall6 but will copy the found in another
location on the CONFIG_PATH.
When compiling for direct use by Shorewall6, causes the contents of the local module or helpers file to be copied into the compiled
script. When set to No or not set, the compiled script reads the file itself.
EXPORTPARAMS={Yes|No}
Deprecated beginning with Shorewall 4.4.17.
Beginning with Shorewall 4.4.17, the variables set in the 'params' file at compile time are available at run time with EXPORTPARAMS=No.
As a consequence, beginning with that version the recommended setting is EXPORTPARAMS=No.
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 output.
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 which is the recommended setting unless you are running Shorewall6 Lite.
FASTACCEPT={Yes|No}
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).
Note
FASTACCEPT=Yes is incompatible with BLACKLISTNEWONLY=No.
FORWARD_CLEAR_MARK={Yes|No}
Added in Shorewall 4.4.11 Beta 3. Traditionally, Shorewall has cleared the packet mark in the first rule in the mangle FORWARD chain.
This behavior is maintained with the default setting of this option (FORWARD_CLEAR_MARK=Yes). If FORWARD_CLEAR_MARK is set to 'No',
packet marks set in the mangle PREROUTING chain are retained in the FORWARD chains.
GEOIPDIR=[pathname]
Added in Shorewall 4.5.4. Specifies the pathname of the directory containing the GeoIP Match database. See
http://www.shorewall.net/ISOCODES.html. If not specified, the default value is /usr/share/xt_geoip/LE which is the default location of
the little-endian database.
HIGH_ROUTE_MARKS={Yes|No}
Deprecated in Shorewall 4.4.26 in favor of PROVIDER_OFFSET.
You may set HIGH_ROUTE_MARKS=Yes in to effectively divide the packet mark and connection mark into two mark fields.
The width of the fields are determined by the setting of the WIDE_TC_MARKS option.
When WIDE_TC_MARKS=No (the default):
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.
When WIDE_TC_MARKS=Yes:
1. The MARK field in the providers file must have a value that is a multiple of 65536 (using hex representation, the values are
0x010000-0xFF0000 with the low-order 16 bits being zero).
2. You may only set those mark values in the PREROUTING chain.
3. Marks used for traffic shaping must be in the range of 1-16383 and may still not be set in the PREROUTING chain.
Regardless of the setting of WIDE_TC_MARKS, 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.
IMPLICIT_CONTINUE={Yes|No}
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[10](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[11](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).
IP=[pathname]
If specified, gives the pathname of the 'ip' executable. If not specified, 'ip' is assumed and the utility will be located using the
current PATH setting.
IP_FORWARDING=[On|Off|Keep]
This rather useless parameter determines whether Shorewall6 enables or disables IPV6 Packet Forwarding on all interfaces
(/proc/sys/net/ipv6/config/all/forwarding). 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.
IP6TABLES=[pathname]
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 directory.
IPSET=[pathname]
If specified, gives the pathname of the 'ipset' executable. If not specified, 'ipset' is assumed and the utility will be located using
the current PATH setting.
IPSET_WARNINGS={Yes|No}
Added in Shorewall 4.5.2. Default is Yes. When set, causes the rules compiler to issue a warning when:
o The compiler is being run by root and an ipset specified in the configuration does not exists. Only one warning is issued for each
missing ipset.
o When [src] is specified in a destination column and when [dst] is specified in a source column.
KEEP_RT_TABLES={Yes|No}
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.
LEGACY_FASTSTART={Yes|No}
Added in Shorewall6 4.4.20. If not specified, the default is Yes which preserves the legacy behavior of start -f (the modification
times of the files in /etc/shorewall6 are compare with that of /var/lib/shorewall6/restore). If set to No, then the times are compared
with that of /var/lib/shorewall6/firewall, which is consistant with the way that restart -f works.
LOAD_HELPERS_ONLY={Yes|No}
Added in Shorewall 4.4.7. When set to Yes, restricts the set of modules loaded by shorewall to those listed in
/var/lib/shorewall6/helpers and those that are actually used. When not set, or set to the empty value, LOAD_HELPERS_ONLY=No is assumed.
LOCKFILE=[pathname]
Specifies the name of the Shorewall6 lock file, used to prevent simultaneous state-changing commands. If not specified,
${VARDIR}/shorewall6/lock is assumed (${VARDIR} is normally /var/lib but can be changed when Shorewall-core is installed -- see the
output of shorewall6 show vardir).
LOG_VERBOSITY=[number]
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 assumed.
LOGALLNEW=[log-level]
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.
o The table name is used as the chain name in the log prefix.
o 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:
Shorewall:nat:PREROUTING
Important
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.
Caution
Do not use this option if the resulting log messages will be sent to another system.
LOGFILE=[pathname]
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.
LOGFORMAT=["formattemplate"]
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.
Note
The setting of LOGFORMAT has an effect of the permitted length of zone names. See shorewall6-zones[10] (5).
LOGLIMIT=[[{s|d}:]rate/{sec|min|hour|day}[:burst]]
Added in Shorewall 4.4.12. Limits the logging rate, either overall, or by source or destination IP address.
If the value starts with 's:' then logging is limited per source IP. If the value starts with 'd:', then logging is limited per
destination IP. Otherwise, the overall logging rate is limited.
If burst is not specified, then a value of 5 is assumed.
LOGBURST=[burst]
Deprecated in Shorewall 4.4.12.
LOGRATE=[rate/{minute|second}]
As of Shorewall 4.4.12, these parameters are Deprecated.
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. If you supply one of these, then you should also supply the other.
Example:
LOGRATE=10/minute
LOGBURST=5
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, 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.
LOGTAGONLY=[Yes|No]
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.
MACLIST_DISPOSITION=[ACCEPT|DROP|REJECT|A_DROP|A_REJECT]
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.
A_DROP and A_REJECT are audited versions of DROP and REJECT respectively and were added in Shorewall 4.4.20. They require AUDIT_TARGET
in the kernel and ip6tables.
MACLIST_LOG_LEVEL=[log-level]
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="").
MACLIST_TABLE=[filter|mangle]
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.
MACLIST_TTL=[number]
The performance of configurations with a large numbers of entries in shorewall-maclist[12](5) can be improved by setting the
MACLIST_TTL variable in shorewall.conf[13](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[12](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).
MANGLE_ENABLED=[Yes|No]
Determines whether Shorewall will generate rules in the Netfilter mangle table. Setting MANGLE_ENABLED=No disables all Shorewall
features that require the mangle table. The default is MANGLE_ENABLED=Yes.
MARK_IN_FORWARD_CHAIN=[Yes|No]
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.
MASK_BITS=[number]
Added in Shorewall 4.4.26. Number of bits on the right of the 32-bit packet mark to be masked when clearing the traffic shaping mark.
Must be >= TC_BITS and <= PROVIDER_OFFSET (if PROVIDER_OFFSET > 0). Default value and the default values of the other mark layout
options is determined as follows:
Table 1. Default Packet Mark Layout
WIDE_TC_MARKS=No, HIGH_ROUTE_MARKS=No TC_BITS=8, PROVIDER_BITS=8, PROVIDER_OFFSET=0,
MASK_BITS=8
WIDE_TC_MARKS=No, HIGH_ROUTE_MARKS=Yes TC_BITS=8, PROVIDER_BITS=8, PROVIDER_OFFSET=8,
MASK_BITS=8
WIDE_TC_MARKS=Yes, HIGH_ROUTE_MARKS=No TC_BITS=14, PROVIDER_BITS=8, PROVIDER_OFFSET=0,
MASK_BITS=16
WIDE_TC_MARKS=Yes, HIGH_ROUTE_MARKS=Yes TC_BITS=14, PROVIDER_BITS=8, PROVIDER_OFFSET=16,
MASK_BITS=16
MODULE_SUFFIX=["extension ..."]
The value of this option determines the possible file extensions of kernel modules. The default value is "ko ko.gz o o.gz gz".
MODULESDIR=[pathname[:pathname]...]
This parameter specifies the directory/directories where your kernel netfilter modules may be found. If you leave the variable empty,
Shorewall6 will supply "/lib/modules/`uname -r`/kernel/net/ipv4/netfilter:/lib/modules/`uname -r`/kernel/net/ipv4/netfilter".
MUTEX_TIMEOUT=[seconds]
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 assumed.
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.
OPTIMIZE=[value]
The specified value enables certain optimizations. Each optimization category is associated with a power of two. To enable multiple
optimization categories, simply add their corresponding numbers together.
o Optimization category 1 - Traditionally, Shorewall has created rules for the complete matrix of host groups defined by the zones,
interfaces and hosts files[14]. 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 the 1 bit in OPTIMIZE.
The 1 bit 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.
o Optimization category 2 - Added in Shorewall 4.4.7. When set, suppresses superfluous ACCEPT rules in a policy chain that implements
an ACCEPT policy. Any ACCEPT rules that immediately preceed the final blanket ACCEPT rule in the chain are now omitted.
o Optimization category 4 - Added in Shorewall 4.4.7. When set, causes short chains (those with less than 2 rules) to be optimized
away. The following chains are excluded from optimization:
o accounting chains (unless OPTIMIZE_ACCOUNTING=Yes)
o action chains (user-defined)
o 'blacklst' chain
o dynamic
Additionally:
o If a built-in chain has a single rule that branches to a second chain, then the rules from the second chain are moved to the
built-in chain and the target chain is omitted.
o Chains with no references are deleted.
o Accounting chains are subject to optimization if the OPTIMIZE_ACCOUNTING option is set to 'Yes'.
o If a chain ends with an unconditional branch to a second chain (other than to 'reject'), then the branch is deleted from the
first chain and the rules from the second chain are appended to it.
An additional optimization was added in Shorewall 4.5.4. If the last rule in a chain is an unqualified jump to a simple target,
then all immediately preceding rules with the same simple target are omitted.
For example, consider this chain:
-A fw-net -p udp --dport 67:68 -j ACCEPT
-A fw-net -p udp --sport 1194 -j ACCEPT
-A fw-net -p 41 -j ACCEPT
-A fw-net -j ACCEPT
Since all of the rules are jumps to the simple target ACCEPT, this chain is totally optimized away and jumps to the chain are
replace with jumps to ACCEPT.
o Optimization category 8 - Added in Shorewall 4.4.9. When set, causes chains with identical rules to be collapsed into a single
chain.
o Optimization category 16 - Added in Shorewall 4.4.26. When set, causes sequences of compatible rules to be combined into a single
rule. Rules are considered compatible if they differ only in their destination ports and comments.
A sequence of combatible rules is often generated when macros are invoked in sequence.
The ability to combine adjacent rules is limited by two factors:
o Destination port lists may only be combined up to a maximum of 15 ports, where a port-pair counts as two ports.
o Rules may only be combined until the length of their concatinated comment reaches 255 characters.
When either of these limits would be exceeded, the current combined rule is emitted and the compiler attemts to combine rules
beginning with the one that would have exceeded the limit. Adjacent combined comments are separated by ', '. Empty comments at the
front of a group of combined comments are replaced by 'Others and'. Empty comments at the end of a group of combined comments are
replaced by 'and others'.
Example 1:
Rules with comments "FOO", <empty> and "BAR" would result in the combined comment "FOO and others, BAR".
Example 2:
Rules with comments <empty>, "FOO" and "BAR" would reult in the combined comment "Others and FOO, BAR". Note: Optimize level 16
requires "Extended Multi-port Match" in your iptables and kernel.
The default value is zero which disables all optimizations.
OPTIMIZE_ACCOUNTING=[Yes|No]
Added in Shorewall 4.4.7. If set to Yes, Shorewall accounting changes are subject to optimization (OPTIMIZE=4,5,6 or 7). If not
specified or set to the empty value, OPTIMIZE_ACCOUNTING=No is assumed.
PATH=pathname[:pathname]...
Determines the order in which Shorewall6 searches directories for executable files.
PERL=pathname
Added in Shorewall 4.4.11 RC1. Specifies the path name of the Perl executable. Default is /usr/bin/perl. If the pathname specified by
this option does not exist or the named file is not executable, then Shorewall6 falls back to /usr/bin/perl/
PROVIDER_BITS=[number]
Added in Shorewall 4.4.26. The number of bits in the 32-bit packet mark to be used for provider numbers. May be zero. See MASK_BITS
above for default value.
PROVIDER_OFFSET=[number]
Added in Shorewall 4.4.26. The offset from the right (low-order end) of the provider number field in the 32-bit packet mark. If
non-zero, must be >= TC_BITS (Shorewall automatically adjusts PROVIDER_OFFSET's value). PROVIDER_OFFSET + PROVIDER_BITS + ZONE_BITS
must be < 32. See MASK_BITS above for default value.
RCP_COMMAND="command"
RSH_COMMAND="command"
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:.RS 4 RSH_COMMAND
RCP_COMMAND
The default values for these are as follows:.RS 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:.RS 4 root - root user. Normally
root but may be overridden using the '-r'
option.
system - The name/IP address
of the remote firewall system.
command - For RSH_COMMAND,
the command to be executed on the firewall system.
files - For RCP_COMMAND, a
space-separated list of files to be copied to the remote
firewall system.
destination - The directory
on the remote system that the files are to be copied
into.
RELATED_DISPOSITION=[ACCEPT|A_ACCEPT|A_DROP|A_REJECT|DROP|REJECT]
Added in Shorewall 4.4.27. Shorewall has traditionally ACCEPTed RELATED packets that don't match any rule in the RELATED section of
shorewall6-rules[15] (5). Concern about the safety of this practice resulted in the addition of this option. When a packet in RELATED
state fails to match any rule in the RELATED section, the packet is disposed of based on this setting. The default value is ACCEPT for
compatibility with earlier versions.
RELATED_LOG_LEVEL=log-level
Added in Shorewall 4.4.27. Packets in the related state that do not match any rule in the RELATED section of shorewall6-rules[16] (5)
are logged at this level. The default value is empty which means no logging is performed.
REQUIRE_INTERFACE=[Yes|No]
Added in Shorewall 4.4.10. The default is No. If set to Yes, at least one optional interface must be up in order for the firewall to be
in the started state. Intended to be used with the Shorewall Init Package[17].
RESTOREFILE=filename
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 commands.
SHOREWALL_SHELL=[pathname]
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.
SMURF_DISPOSITION=[DROP|A_DROP]
Added in Shorewall 4.4.20. The default setting is DROP which causes smurf packets (see the nosmurfs option in
shorewall-interfaces[18](5)) to be dropped. A_DROP causes the packets to be audited prior to being dropped and requires AUDIT_TARGET
support in the kernel and ip6tables.
SMURF_LOG_LEVEL=[log-level]
Specifies the logging level for smurf packets (see the nosmurfs option in shorewall6-interfaces[19](5)). If set to the empty value (
SMURF_LOG_LEVEL="" ) then smurfs are not logged.
SFILTER_DISPOSITION=[DROP|REJECT|A_DROP|A_REJECT]
Added in Shorewall 4.4.20. Determines the disposition of packets matching the filter option (see shorewall6-interfaces[19](5)) and of
hairpin packets on interfaces without the routeback option.[20] interfaces without the routeback option.
SFILTER_LOG_LEVEL=log-level
Added on Shorewall 4.4.20. Determines the logging of packets matching the filter option (see shorewall6-interfaces[19](5)) and of
hairpin packets on interfaces without the routeback option.[21] interfaces without the routeback option. The default is info. If you
don't wish for these packets to be logged, use SFILTER_LOG_LEVEL=none.
STARTUP_ENABLED={Yes|No}
Determines if Shorewall6 is allowed to start. As released from shorewall.net, 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.
STARTUP_LOG=[pathname]
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.
SUBSYSLOCK=[pathname]
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.
TC=[pathname]
If specified, gives the pathname of the 'tc' executable. If not specified, 'tc' is assumed and the utility will be located using the
current PATH setting.
TC_BITS=[number]
Added in Shorewall 4.4.26. The number of bits at the low end of the 32-bit packet mark to be used for traffic shaping marking. May be
zero. See MASK_BITS above for default value.
TC_ENABLED=[Yes|No|Internal|Shared]
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.
Beginning with Shorewall 4.4.15, if you set TC_ENABLED=Shared or shared, then you should create symbolic links from your Shorewall6
configuration directory (normally /etc/shorewall6/) to your Shorewall tcdevices and tcclasses files. This allows the compiler to have
access to your Shorewall traffic shaping configuration so that it can validate CLASSIFY rules in shorewall6-tcrules[22] (5).
Warning
If you also run Shorewall and if you have TC_ENABLED=Internal in your shorewall-conf[9](5), then you will want TC_ENABLED=No or
TC_ENABLED=Shared in this file.
TC_EXPERT={Yes|No}
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 shorewall6-providers[23](5).
If you know what you are doing, you can set TC_EXPERT=Yes and Shorewall6 will not include these cautionary checks.
TC_PRIOMAP=map
Added in Shorewall 4.4.6. Determines the mapping of a packet's TOS field to priority bands. See shorewall6-tcpri[24](5). The map
consists of 16 space-separated digits with values 1, 2 or 3. A value of 1 corresponds to Linux priority 0, 2 to Linux priority 1, and 3
to Linux Priority 2. The first entry gives the priority of TOS value 0, the second of TOS value 1, and so on. See tc-prio(8) for
additional information.
The default setting is TC_PRIOMAP="2 3 3 3 2 3 1 1 2 2 2 2 2 2 2 2".
TCP_FLAGS_DISPOSITION=[ACCEPT|DROP|REJECT]
Determines the disposition of TCP packets that fail the checks enabled by the tcpflags interface option (see
shorewall6-interfaces[19](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.
TCP_FLAGS_LOG_LEVEL=[log-level]
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="").
TRACK_PROVIDERS={Yes|No}
Added in Shorewall 4.4.3. When set to Yes, causes the track option to be assumed on all providers defined in
shorewall6-providers[23](5). May be overridden on an individual provider through use of the notrack option. The default value is 'No'.
Beginning in Shorewall 4.4.6, setting this option to 'Yes' also simplifies PREROUTING rules in shorewall6-tcrules[8](5). Previously,
when TC_EXPERT=No, packets arriving through 'tracked' provider interfaces were unconditionally passed to the PREROUTING tcrules. This
was done so that tcrules could reset the packet mark to zero, thus allowing the packet to be routed using the 'main' routing table.
Using the main table allowed dynamic routes (such as those added for VPNs) to be effective. The shorewall6-rtrules[25](5) file was
created to provide a better alternative to clearing the packet mark. As a consequence, passing these packets to PREROUTING complicates
things without providing any real benefit. Beginning with Shorewall 4.4.6, when TRACK_PROVIDERS=Yes and TC_EXPERT=No, packets arriving
through 'tracked' interfaces will not be passed to the PREROUTING rules. Since TRACK_PROVIDERS was just introduced in 4.4.3, this
change should be transparent to most, if not all, users.
USE_DEFAULT_RT=[Yes|No]
Added in Shorewall6 4.4.25. When set to 'Yes', this option causes the Shorewall6 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 Shorewall6-generated routing rules.
So changes to the main table will affect the routing of packets by default.
When USE_DEFAULT_RT=Yes:
1. Both the DUPLICATE and the COPY columns in shorewall6-providers[23](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 shorewall6-routing_rules[26](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.
6. You should disable all default route management outside of Shorewall6. 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.
USE_PHYSICAL_NAMES=[Yes|No]
Added in Shorewall 4.4.27. Normally, when Shorewall creates a Netfilter chain that relates to an interface, it uses the interfaces's
logical name as the base of the chain name. For example, if the logical name for an interface is OAKLAND, then the input chain for
traffic arriving on that interface would be 'OAKLAND_in'. If this option is set to Yes, then the physical name of the interface will be
used the base of the chain name.
VERBOSITY=[number]
Shorewall6 has traditionally been very noisy (produced lots of output). You may set the default level of verbosity using the VERBOSITY
OPTION.
Values are:
0 - Silent. You may make it more verbose using the -v
option
1 - Major progress messages displayed
2 - All progress messages displayed (pre Shorewall6-3.2.0
behavior)
If not specified, then 2 is assumed.
WIDE_TC_MARKS={Yes|No}
Deprecated in Shorewall 4.4.26 in favor of TC_BITS and MASK_BITS.
When set to No (the default), traffic shaping marks are 8 bytes wide (possible values are 1-255). When WIDE_TC_MARKS=Yes, traffic
shaping marks are 14 bytes wide (values 1-16383). The setting of WIDE_TC_MARKS also has an effect on the HIGH_ROUTE_MARKS option (see
above).
ZONE_BITS=[number]
Added in Shorewall 4.4.26. When non-zero, enables automatic packet marking by source zone and determines the number of bits in the
32-bit packet mark to be used for the zone mark. Default value is 0.
ZONE2ZONE={2|-}
Added in Shorewall 4.4.4. This option determines how Shorewall constructs chain names involving zone names and/or 'all'. The default is
'2' (e.g., fw2net).
FILES
/etc/shorewall6/shorewall6.conf
SEE ALSO
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),
shoewall6-netmap(5),shorewall6-params(5), shorewall6-policy(5), shorewall6-providers(5), shorewall6-proxyarp(5), shorewall6-rtrules(5),
shorewall6-routestopped(5), shorewall6-rules(5), shorewall6-tcclasses(5), shorewall6-tcdevices(5), shorewall6-tcrules(5),
shorewall6-tos(5), shorewall6-tunnels(5), shorewall6-zones(5)
NOTES
1. shorewall6-policy
http://www.shorewall.net/manpages6/shorewall6-policy.html
2. shorewall6-accounting
http://www.shorewall.net/manpages6/shorewall6-accounting.html
3. shorewall-accounting
http://www.shorewall.net/manpages6/shorewall-accounting.html
4. shorewall6-routestopped
http://www.shorewall.net/manpages6/shorewall6-routestopped.html
5. shorewall6-rules
http://www.shorewall.net/manpages6/shorewall6-rules.html
6. shorewall6-blrules
http://www.shorewall.net/manpages6/shorewall6-blrules.html
7. shorewall-blrules
http://www.shorewall.net/manpages6/???
8. shorewall6-tcrules
http://www.shorewall.net/manpages6/shorewall6-tcrules.html
9. shorewall-conf
http://www.shorewall.net/manpages6/../manpages/shorewall.conf.html
10. shorewall6-zones
http://www.shorewall.net/manpages6/shorewall6-zones.html
11. shorewall6-nesting
http://www.shorewall.net/manpages6/shorewall6-nesting.html
12. shorewall-maclist
http://www.shorewall.net/manpages6/shorewall-maclist.html
13. shorewall.conf
http://www.shorewall.net/manpages6/shorewall.conf.html
14. the complete matrix of host groups defined by the zones, interfaces and hosts files
http://www.shorewall.net/manpages6/../ScalabilityAndPerformance.html
15. shorewall6-rules
http://www.shorewall.net/manpages6/manpages6/shorewall6-rules.html
16. shorewall6-rules
http://www.shorewall.net/manpages6/manpages/shorewall-rules.html
17. Shorewall Init Package
http://www.shorewall.net/manpages6/../Manpages/shorewall-init.html
18. shorewall-interfaces
http://www.shorewall.net/manpages6/shorewall-interfaces.html
19. shorewall6-interfaces
http://www.shorewall.net/manpages6/shorewall6-interfaces.html
20. Hairpin packets are packets that are routed out of the same interface that they arrived on.
21. Hairpin packets are packets that are routed out of the same interface that they arrived on.
22. shorewall6-tcrules
http://www.shorewall.net/manpages6/shorewall-tcrules.html
23. shorewall6-providers
http://www.shorewall.net/manpages6/shorewall6-providers.html
24. shorewall6-tcpri
http://www.shorewall.net/manpages6/shorewall6-tcpri.html
25. shorewall6-rtrules
http://www.shorewall.net/manpages6/shorewall6-rtrules.html
26. shorewall6-routing_rules
http://www.shorewall.net/manpages6/shorewall6-routing_rules.html
[FIXME: source] 06/28/2012 SHOREWALL6.CONF(5)