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 specify. 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 (IPv4 only) 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).
Note
If you want to specify parameters to ULOG or NFLOG (e.g.,
NFLOG(1,0,1)), then you must quote the setting.
Example:
Beginning with Shorewall 5.0.0, the log level may be followed by a
colon (":") and a log tag. The log tag normally follows the packet
disposition in Shorewall-generated Netfilter log messages, separated from
the disposition by a colon (e.g, "DROP:mytag"). See LOGTAGONLY
below for additional information.
Beginning with Shorewall 4.4.22, LOGMARK is also a valid level
which logs the packet's mark value along with the other usual information.
The syntax is:
LOGMARK[(priority)]
where priority is one of the levels listed in the list
above. If omitted, the default is info (6).
The following options may be set in shorewall.conf.
ACCEPT_DEFAULT={action[(parameters)][:level][,...]|none}
BLACKLIST_DEFAULT={action[(parameters)][:level][,...]|none}
DROP_DEFAULT={action[(parameters)][:level][,...]|none}
NFQUEUE_DEFAULT={action[(parameters)][:level][,...]|none}
QUEUE_DEFAULT={action[(parameters)][:level][,...]|none}
REJECT_DEFAULT={action[(parameters)][:level][,...]|none}
In earlier Shorewall versions, a "default
action" for DROP and REJECT policies was specified in the file
/usr/share/shorewall/actions.std.
In Shorewall 4.4.0, the DROP_DEFAULT, REJECT_DEFAULT,
ACCEPT_DEFAULT, QUEUE_DEFAULT and NFQUEUE_DEFAULT options were 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. The
name may optionally be followed by a comma-separated list of
parameters enclosed in parentheses if the specified action accepts
parameters (e.g., 'Drop(audit)').
c) None or none
Prior to Shorewall 5.1.2, the default values are:
DROP_DEFAULT="Drop"
REJECT_DEFAULT="Reject"
BLACKLIST_DEFAULT="Drop" (added in Shorewall
5.1.1)
ACCEPT_DEFAULT="none"
QUEUE_DEFAULT="none"
NFQUEUE_DEFAULT="none"
Beginning with Shorewall 5.1.2, the default value is 'none' for all of these.
Note that the sample configuration files do, however, provide settings for
DROP_DEFAULT, BLACKLIST_DEFAULT and REJECT_DEFAULT.
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).
You can pass parameters to the specified action (e.g.,
myaction(audit,DROP)).
Beginning with Shorewall 4.5.10, the action name can be followed
optionally by a colon and a log level. The level will be applied to
each rule in the action or body that does not already have a log level.
Beginning with Shorewall 5.1.2, multiple
action[(parameters)][:level] specifications may be
listed, separated by commas.
ACCOUNTING=[Yes|No]
Added in Shorewall 4.4.7. If set to Yes, Shorewall
accounting is enabled (see shorewall-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[2](5).
ADD_IP_ALIASES=[Yes|No]
This parameter determines whether Shorewall automatically
adds the external address(es) in
shorewall-nat[3](5), and is only
available in IPv4 configurations. 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.
Warning
Addresses added by ADD_IP_ALIASES=Yes are deleted and re-added during
shorewall reload and
shorewall restart. As a consequence,
connections using those addresses may be severed.
ADD_SNAT_ALIASES=[Yes|No]
This parameter determines whether Shorewall automatically
adds the SNAT ADDRESS in
shorewall-masq[4](5), and is only available in
IPv4 configurations. 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.
Warning
Addresses added by ADD_SNAT_ALIASES=Yes are deleted and re-added during
shorewall reload and
shorewall restart. As a consequence,
connections using those addresses may be severed.
ADMINISABSENTMINDED=[Yes|No]
The value of this variable affects Shorewall's stopped
state. The behavior differs depending on whether
shorewall-routestopped[5](5) or
shorewall-stoppedrules[6](5) is
used:
routestopped
When ADMINISABSENTMINDED=No, only traffic to/from those
addresses listed in routestopped is accepted when Shorewall is stopped. When
ADMINISABSENTMINDED=Yes, in addition to traffic to/from addresses in
routestopped, connections that were active when Shorewall stopped continue to
work and all new connections from the firewall system itself are allowed.
Note that the routestopped file is not supported in Shorewall 5.0
and later versions.
stoppedrules
All existing connections continue to work. To sever all
existing connections when the firewall is stopped, install the conntrack
utility and place the command
conntrack -F in the stopped user exit
(/etc/shorewall/stopped).
If ADMINISABSENTMINDED=No, only new connections matching entries
in stoppedrules are accepted when Shorewall is stopped. Response packets and
related connections are automatically accepted.
If ADMINISABSENTMINDED=Yes, in addition to connections matching
entries in stoppedrules, all new connections from the firewall system itself
are allowed when the firewall is stopped. Response packets and related
connections are automatically accepted.
If this variable is not set or is given the empty value then
ADMINISABSENTMINDED=No is assumed.
ARPTABLES=[pathname]
Added in Shorewall 4.5.12 and available in IPv4 only.
This parameter names the arptables executable to be used by Shorewall. If not
specified or if specified as a null value, then the arptables executable
located using the PATH option is used.
Regardless of how the arptables utility is located (specified via
arptables= or located via PATH), Shorewall uses the arptables-restore and
arptables-save utilities from that same directory.
AUTOCOMMENT=[Yes|No]
Formerly named AUTO_COMMENT. 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>". If not
specified, the AUTO_COMMENT option has a default value of 'Yes'.
AUTOHELPERS=[Yes|No]
Added in Shorewall 4.5.7. When set to
Yes (the
default), the generated ruleset will automatically associate helpers with
applications that require them (FTP, IRC, etc.). When configuring your
firewall on systems running kernel 3.5 or later, it is recommended that you:
1.Set AUTOHELPERS=No.
2.Modify the HELPERS setting (see below) to list the
helpers that you need.
3.Either:
1.Modify shorewall-conntrack[7] (5) to only apply
helpers where they are required; or
2.Specify the appropriate helper in the HELPER column in
shorewall-rules[8] (5).
Note
The macros for those applications requiring a helper automatically specify the
appropriate HELPER where required.
AUTOMAKE=[Yes|No|recursive|depth]
If set, the behavior of the
start,
reload
and
restart commands are changed; if no files in CONFIG_PATH (see
below) have been changed since the last successful
start, reload or
restart command, then the compilation step is skipped and the compiled
script that executed the last
start,
reload or
restart
command is used. If not specified, the default is AUTOMAKE=No.
The setting of the AUTOMAKE option is ignored if the start,
reload or restart command includes a directory name (e.g.,
shorewall restart /etc/shorewall.new).
When AUTOMAKE=Yes, each directory in the CONFIG_PATH was
originally searched recursively for files newer than the compiled script.
That was changed in Shorewall 5.1.10.2 such that only the listed directories
themselves were searched. That broke some configurations that played tricks
with embedded SHELL such as "SHELL cat
/etc/shorewall/rules.d/loc/*.rules". Prior to 5.1.10.2, a change to
a file in or adding a file to /etc/shorewall/rules.d/loc/ would trigger
recompilation. Beginning with 5.1.10.2, such changes would not trigger
recompilation. Beginning with Shorewall 5.2.0, the pre-5.1.10.2 behavior can
be obtained by setting AUTOMAKE=recursive.
Also beginning with Shorewall 5.2.0, AUTOMAKE may be set to a
numeric depth which specifies how deeply each listed directory is to
be searched. AUTOMAKE=1 only searches each directory itself and is
equivalent to AUTOMAKE=Yes. AUTOMAKE=2 will search each directory and its
immediate sub-directories; AUTOMAKE=3 will search each directory, each of
its immediate sub-directories, and each of their immediate sub-directories,
etc.
BALANCE_PROVIDERS=[Yes|No]
Added in Shorewall 5.1.1. When USE_DEFAULT_RT=Yes, this
option determines whether the
balance provider option (see
shorewall-providers(5)[9]) is the default. When BALANCE_PROVIDERS=Yes,
then the
balance option is assumed unless the
fallback,
loose,
load or
tproxy option is specified. If this option
is not set or is set to the empty value, then the default value is the value
of USE_DEFAULT_RT.
BASIC_FILTERS=[Yes|No]
Added in Shorewall-4.6.0. When set to
Yes, causes
entries in
shorewall-tcfilters(5)[10] to generate a basic filter rather
than a u32 filter. This setting requires the Basic Ematch capability in your
kernel and iptables.
Note
One of the advantages of basic filters is that ipset matches are supported in
newer iproute2 and kernel versions. Because Shorewall cannot reliably detect
this capability, use of basic filters is controlled by this option.
The default value is
No which causes u32 filters to be generated.
BLACKLIST=[{ALL|state[,...]}]
where state is one of NEW, ESTABLISHED, RELATED,
INVALID,or UNTRACKED.
Added in Shorewall 4.5.13 to replace the BLACKLISTNEWONLY option.
Specifies the connection tracking states that are to be subject to blacklist
screening. If BLACKLIST is not specified then the states subject to
blacklisting are NEW,ESTABLISHED,INVALID,UNTRACKED.
ALL sends all packets through the blacklist chains.
Note: The ESTABLISHED state may not be specified if FASTACCEPT=Yes
is specified.
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.
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 iptables.
The BLACKLIST_DISPOSITION setting determines the disposition of
packets sent to the blacklog target of
shorewall-blrules[11](5), but otherwise does not affect entries in
that file.
BLACKLIST_LOG_LEVEL=[log-level[:log-tag]]
Formerly named BLACKLIST_LOGLEVEL. 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_LOG_LEVEL=debug). If you do not assign a value or if you
assign an empty value then packets from blacklisted hosts are not logged. The
setting determines the log level of packets sent to the blacklog target
of shorewall-blrules[11](5).
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 Shorewall won't
clear the current traffic control rules during [
re]
start or
reload. This setting is intended for use by people who 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[12](5). If not
specified, CLEAR_TC=Yes is assumed.
Warning
When you specify TC_ENABLED=shared (see below), then you should also specify
CLEAR_TC=No.
COMPLETE=[Yes|No]
Added in Shorewall 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 Shorewall 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:
•You have defined an interface whose effective
physical setting is '+'.
•That interface is assigned to a zone.
•You have no CONTINUE policies or rules.
CONFIG_PATH=[[:]directory[:directory]...]
Specifies where configuration files other than
shorewall[6].conf may be found. CONFIG_PATH is specifies as a list of
directory names separated by colons (":"). When looking for a
configuration file:
•If the command is "try" or a
"<configuration directory>" was specified in the command
(e.g., shorewall [-6] check ./gateway) then the directory given in the
command is searched first.
•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/shorewall/configpath are used. As released
from shorewall.net, that file sets the CONFIG_PATH to
/etc/shorewall:/usr/share/shorewall but your particular distribution may set
it differently. See the output of shorewall show config for the default on
your system.
Beginning with Shorewall 5.1.10, the CONFIG_PATH setting may begin
with a colon (":"), to signal that the first directory
listed will be skipped if the user performing a compilation is not root or
if the configuration is being compiled for export (-e option specified or if
running one of the remote-* commands) . This prevents the compiler from
looking in /etc/shorewall[6]/ when compilation is being done by a non-root
user or if the generated script is to be sent to a remote firewall
system.
DEFER_DNS_RESOLUTION=[Yes|No]
Added in Shorewall 4.5.12. When set to 'Yes' (the
default), DNS names are validated in the compiler and then passed on to the
generated script where they are resolved by ip[6]tables-restore. This is an
advantage if you use AUTOMAKE=Yes and the IP address associated with the DNS
name is subject to change. When DEFER_DNS_RESOLUTION=No, DNS names are
converted into IP addresses by the compiler. This has the advantage that when
AUTOMAKE=Yes, the
start,
reload and
restart commands will
succeed even if no DNS server is reachable (assuming that the configuration
hasn't changed since the compiled script was last generated).
Important
When DEFER_DNS_RESOLUTION=No and AUTOMAKE=Yes and a DNS change makes it
necessary to recompile an existing firewall script, the
-c option must
be used with the
reload or
restart command to force
recompilation.
DELETE_THEN_ADD={Yes|No}
If set to Yes (the default value), entries in the
/etc/shorewall[6]/rtrules 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.
DETECT_DNAT_IPADDRS=[Yes|No]
IPv4 only.
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.
DISABLE_IPV6=[Yes|No]
IPv4 only.
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.
It is important to note that changing DISABLE_IPV6=Yes to
DISABLE_IPV6=No does not enable IPV6. The recommended approach for
enabling IPv6 on your system is:
•Install, configure and start
Shorewall6[13].
•Change DISABLE_IPV6=Yes to DISABLE_IPV6=No in
/etc/shorewall/shorewall.conf.
•Reload Shorewall
DOCKER=[Yes|No]
Added in Shorewall 5.0.6; IPv4 only. When set to
Yes, the generated script will save Docker-generated rules before and
restore them after executing the start, stop, reload and
restart commands. If set to No (the default), the generated
script will delete any Docker-generated rules when executing those commands.
Seehttps://shorewall.org/Docker.html[14] for additional
information.
DOCKER_BRIDGE=[bridgename]
Added in Shorewall 5.2.4; IPv4 only. Specifies the name
of the default Docker bridge. If not specified, the value 'docker0' is
assumed.
DONT_LOAD=[module[,module]...]
Causes Shorewall to not load the listed kernel
modules.
DYNAMIC_BLACKLIST={Yes|No||ipset[-only][,option[,...]][:[setname][:log_level|:log_tag]]]}
Added in Shorewall 4.4.7. When set to
No or
no, chain-based dynamic blacklisting using
shorewall [-6] [-l]
drop,
shorewall [-6] [-l] reject,
shorewall logdrop and
shorewall [-6] [-l] logreject is disabled. Default is
Yes.
Beginning with Shorewall 5.0.8, ipset-based dynamic blacklisting using the
shorewall blacklist command is also supported. The name of the set
(
setname) and the level (
log_level), if any, at which
blacklisted traffic is to be logged may also be specified. The default IPv4
set name is SW_DBL4 and the default IPv6 set name is SW_DBL6. The default log
level is
none (no logging). If
ipset-only is given, then
chain-based dynamic blacklisting is disabled just as if
DYNAMIC_BLACKLISTING=No had been specified.
Possible options are:
src-dst
Normally, only packets whose source address matches an
entry in the ipset are dropped. If src-dst is included, then packets
whose destination address matches an entry in the ipset are also
dropped.
disconnect
The disconnect option was added in Shorewall
5.0.13 and requires that the conntrack utility be installed on the firewall
system. When an address is blacklisted using the blacklist command, all
connections originating from that address are disconnected. if the
src-dst option was also specified, then all connections to that address
are also disconnected.
timeout=seconds
Added in Shorewall 5.0.13. Normally, Shorewall creates
the dynamic blacklisting ipset with timeout 0 which means that entries are
permanent. If you want entries in the set that are not accessed for a period
of time to be deleted from the set, you may specify that period using this
option. Note that the
blacklist command can override the ipset's
timeout setting.
Important
Once the dynamic blacklisting ipset has been created, changing this option
setting requires a complete restart of the firewall;
shorewall [-6]
restart if RESTART=restart, otherwise
shorewall [-6] [-l] stop
&& shorewall [-6] [-l] start
log
Added in Shorewall 5.2.5. When specified, successful
'blacklist' and 'allow' commands will log a message to the system log.
noupdate
Added in Shorewall 5.2.5. Normally, once an address has
been blacklisted, each time that a packet is received from the packet, the
ipset's entry for the address is updated to reset the timeout to the value
specifyed in the timeout option above. Setting the noupdate
option, inhibits this resetting of the entry's timeout. This option is ignored
when the timeout option is not specified.
When ipset-based dynamic blacklisting is enabled, the contents of
the blacklist will be preserved over stop/reboot/start
sequences.
EXPAND_POLICIES={Yes|No}
Normally, when the SOURCE or DEST columns in
shorewall-policy(5) contains 'all', a single policy chain is created and thes
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 'net-all' ('net2all if ZONE2ZONE=2) 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 Shorewall Lite (
shorewall [-6] remote-start,
shorewall
[-6] remote-reload, shorewall [-6] remote-restart or
shorewall [-6]
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/shorewall[6] but will copy those found in another location on the
CONFIG_PATH.
When compiling for direct use by Shorewall, 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.
FASTACCEPT={Yes|No}
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 'loc-net' or 'loc2net' chain,
depending on the setting of ZONE2ZONE (see below).
If you set FASTACCEPT=Yes, then ESTABLISHED/RELATED 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[8](5).
FIREWALL=[dnsname-or-ip-address]
This option was added in Shorewall 5.0.13 and may be used
on an administrative system in directories containing the configurations of
remote firewalls. The contents of the variable are the default value for the
system parameter to the remote-start, remote-reload and
remote-restart commands.
FORWARD_CLEAR_MARK={Yes|No}
Added in Shorewall 4.4.11. 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
https://shorewall.org/ISO-3661.html[15]. If not specified, the default
value is /usr/share/xt_geoip/LE which is the default location of the
little-endian database.
HELPERS=[helper[,helper...]]
Added in Shorewall 4.5.7. This option specifies a
comma-separated list naming the Netfilter application helpers that are to be
enabled. If not specified, the default is to enable all helpers.
Possible values for helper are:
•amanda
•ftp
•h323
•irc
•netbios-ns
•none - This special value was added in
Shorewall 4.5.16 and indicates that no helpers are to be enabled. It also
prevents the compiler for probing for helper support; such probing generates
messages on the system log of the form "xt_CT: No such helper XXX"
where XXX is the helper name. When used, none must be the only helper
specified.
•pptp
•sane
•sip
•snmp
•tftp
When HELPERS is specified on a system running Kernel 3.5.0 or
later, automatic association of helpers to connections is disabled.
IGNOREUNKNOWNVARIABLES=[Yes|No]
Added in Shorewall 4.5.11. Normally, if an unknown shell
variable is encountered in a configuration file (except in ?IF and ?ELSIF
directives), the compiler raises a fatal error. If IGNOREUNKNOWNVARIABLES is
set to Yes, then such variables simply expand to an empty string.
Default is No.
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 shorewall-zones[16](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[17](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).
INVALID_DISPOSITION=[A_DROP|A_REJECT|DROP|REJECT|CONTINUE]
Added in Shorewall 4.5.13. Shorewall has traditionally
passed INVALID packets through the NEW section of shorewall-rules[8]
(5). When a packet in INVALID state fails to match any rule in the INVALID
section, the packet is disposed of based on this setting. The default value is
CONTINUE for compatibility with earlier versions.
INVALID_LOG_LEVEL=log-level[:log-tag]
Added in Shorewall 4.5.13. Packets in the INVALID state
that do not match any rule in the INVALID section of shorewall-rules[8]
(5) are logged at this level. The default value is empty which means no
logging is performed.
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 IPv4 parameter determines whether Shorewall enables
or disables IPv4 Packet Forwarding (/proc/sys/net/ipv4/ip_forward). In an IPv6
configuration, this parameter determines the setting of
/proc/sys/net/ipv6/config/all/ip_forwarding.
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.
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:
•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.
•When [src] is specified in a destination column
and when [dst] is specified in a source column.
IPTABLES=[pathname]
IPv4 only.
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.
IP6TABLES=[pathname]
IPv6 only.
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.
KEEP_RT_TABLES={Yes|No}
IPv4: When set to
Yes, this option prevents
generated scripts 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,
restore,
reload or
restart
command. IPv6: 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,
restore,
reload or
restart command.
Important
When both IPv4 and IPv6 Shorewall configurations are present, KEEP_RT_TABLES=No
should be specified in only one of the two configurations unless the two
provider configurations are identical with respect to interface and provider
names and numbers.
The default is KEEP_RT_TABLES=No.
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/shorewall[6]/helpers and those that are actually used. When not set,
or set to the empty value, LOAD_HELPERS_ONLY=No is assumed in Shorewall
versions 5.2.2 and earlier. Beginning with Shorewall 5.2.3, the
LOAD_HELPERS_ONLY option is removed, and the behavior is as if
LOAD_HELPERS_ONLY=Yes had been specified.
LOCKFILE=[pathname]
Specifies the name of the Shorewall[6] lock file, used to
prevent simultaneous state-changing commands. If not specified,
${VARDIR}/shorewall[6]/lock is assumed (${VARDIR} is normally /var/lib but can
be changed when Shorewall-core is installed -- see the output of shorewall
show vardir).
LOG_BACKEND=[backend]
Added in Shorewall 4.6.4. LOG_BACKEND determines the
logging backend to be used for the
iptrace command (see
shorewall(8)[18]).
backend is one of:
LOG
Use standard kernel logging.
ULOG
IPv4 only.
Use ULOG logging to ulogd.
netlink
Use netlink logging to ulogd version 2 or later.
LOG_ZONE=[src|dst|both]
Added in Shorewall 5.2.0. When a log message is issued
from a chain that relates to a pair of zones (e.g, 'fw-net'), the chain name
normally appears in the log message (unless LOGTAGONLY=Yes and a log tag is
specified). This can prevent OPTIMIZE category 8 from combining chains which
are identical except for the names of the zones involved. LOG_ZONE allows for
only the source or destination zone to appear in the messages by setting
LOG_ZONE to src or dest respectively. If LOG_ZONE=both
(the default), then the full chain name is included in log messages.
LOG_LEVEL=log-level[:log-tag]
Added in Shorewall 5.1.2. Beginning with that release,
the sample configurations use this as the default log level and changing it
will change all packet logging done by the configuration. In any configuration
file (except
shorewall-params(5)[19]), $LOG_LEVEL will expand to this
value.
LOG_MARTIANS=[Yes|No|Keep]
IPv4 only.
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. The default
value is 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[20](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[20](5).
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 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 as follows in versions
prior to 5.1.0:
In Shorewall 5.1.0 and later releases, the log prefix is:
Important
To help insure that all packets in the NEW state are logged, rate limiting
(LOGLIMIT) 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|systemd]
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. For further information, see
shorewall-logging(8)[21]. Beginning with Shorewall 5.0.10.1, you may
specify
systemd to use
journelctl -r to read the log.
LOGFORMAT=["formattemplate"]
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.
Note
The setting of LOGFORMAT has an effect of the permitted length of zone names.
See
shorewall-zones[16] (5).
Caution
Beginning with Shorewall 5.1.0, the default and sample shorewall[6].conf files
set LOGFORMAT="%s %s ".
Regardless of the LOGFORMAT setting, Shorewall IPv4 log messages
that use this LOGFORMAT can be uniquely identified using the following
regular expression:
'IN=.* OUT=.* SRC=.*\..* DST='
and Shorewall IPv6 log messages can be uniquely identified using the following
regular expression:
'IN=.* OUT=.* SRC=.*:.* DST='
To match all Netfilter log messages (Both IPv4 and IPv6 and regardless of the
LOGFORMAT setting), use:
'IN=.* OUT=.* SRC=.* DST='
LOGLIMIT=[[{s|d}:]rate/{sec|second|min|minute|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.
The keywords second and minute are accepted
beginning with Shorewall 4.6.13.
LOGTAGONLY=[Yes|No]
Using LOGFORMAT=“Shorewall:%s:%s:”, chain
names may not exceed 5 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.
Beginning with Shorewall 4.5.12, when LOGTAGONLY=Yes, you have
more control over the generated log prefix. Beginning with that release, the
tag is interpreted as a chain name and a disposition separated
by a comma. So this rule:
#ACTION SOURCE DEST
LOG:info:foo,bar net fw
would generate the following log prefix when using
LOGFORMAT=“Shorewall:%s:%s:”:
Shorewall:foo:bar:
Similarly,
#ACTION SOURCE DEST
LOG:info:,bar net fw
would generate
Shorewall:net2fw:bar:
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 ip[6]tables.
MACLIST_LOG_LEVEL=[log-level[:log-tag]]
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 or MACLIST_DISPOSITION=A_REJECT with
MACLIST_TABLE=mangle.
MACLIST_TTL=[number]
The performance of configurations with a large numbers of
entries in
shorewall-maclist[22](5) can be improved by setting the
MACLIST_TTL variable in
shorewall[6].conf[23](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[22](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.
MINIUPNPD=[Yes|No]
Added in Shorewall 5.0.8. If set to Yes, Shorewall will
create a chain in the nat table named MINIUPNPD-POSTROUTING and will add jumps
from POSTROUTING to that chain for each interface with the upnpd option
specified. Default is No.
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 shorewall [-6] 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).
Prior to Shorewall 5.0.0, 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 |
From 5.0.0 onward, the default value of MASK_BITS is 8, the
default value of PROVIDER_BITS, TC_BITS, MASK_BITS and PROVIDER_OFFSET is 8.
MODULESDIR=[[+]pathname[:pathname]...]
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/kernel/net/ipv${g_family}/netfilter:/lib/modules/$uname/kernel/net/netfilter:/lib/modules/$uname/kernel/net/sched:/lib/modules/$uname/extra:/lib/modules/$uname/extra/ipset"
where
uname holds the output of '
uname -r' and
g_family
holds '4' in IPv4 configurations and '6' in IPv6 configurations.
The option plus sign ('+') was added in Shorewall 5.0.3 and causes
the listed pathnames to be appended to the default list above.
MULTICAST=[Yes|No]
IPv4 only.
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 /etc/shorewall/hosts.
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.
MUTEX_TIMEOUT=[seconds]
The value of this variable determines the number of
seconds that programs will wait for exclusive access to the Shorewall[6] 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 shorewall [-6]
restart command.
NFACCT=[pathname]
Added in Shorewall 4.5.7. Specifies the pathname of the
nfacct utility. If not specified, Shorewall will use the PATH setting to find
the program.
NULL_ROUTE_RFC1918=[Yes|No|blackhole|unreachable|prohibit]
IPv4 only.
When set to Yes, causes Shorewall to null-route the IPv4 address
ranges reserved by RFC1918. The default value is 'No'.
When combined with route filtering (ROUTE_FILTER=Yes or
routefilter in shorewall-interfaces[20](5)), this option
ensures that packets with an RFC1918 source address are only accepted from
interfaces having known routes to networks using such addresses.
Beginning with Shorewall 4.5.15, you may specify blackhole,
unreachable or prohibit to set the type of route to be
created. See
https://shorewall.org/MultiISP.html#null_routing[24].
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.
Beginning with Shorewall 4.5.20, you may specify OPTIMIZE=All to
enable all optimization categories, and you may also specify OPTIMIZE=None
to disable optimization.
•Optimization category 1 - Traditionally,
Shorewall has created rules for the complete matrix of host groups defined by
the zones, interfaces and hosts files. Any traffic that didn't correspond to
an element of that matrix was rejected in one of the built-in 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.
Note
Optimization level 1 is ignored when optimization level 4 is also selected,
since level 4 performs similar optimizations in a more robust way.
•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 precede the
final blanket ACCEPT rule in the chain are now omitted.
•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:
•accounting chains (unless
OPTIMIZE_ACCOUNTING=Yes)
•action chains (user-defined)
•'blacklst' chain
•dynamic
•forwardUPnP
•UPnP (nat table)
Additionally:
•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.
•Chains with no references are deleted.
•Accounting chains are subject to optimization if
the OPTIMIZE_ACCOUNTING option is set to 'Yes'.
•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.
•Optimization category 8 - Added in Shorewall
4.4.9. When set, causes chains with identical rules to be collapsed into a
single chain.
Warning
While Optimization category 8 can significantly reduce the size of the generated
iptables ruleset, it can also take significant system resources during
compilation. If you find that compilation takes an unreasonably long time, try
disabling this category by setting OPTIMIZE=23.
•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 compatible rules is often generated when macros are
invoked in sequence.
The ability to combine adjacent rules is limited by two
factors:
•Destination port lists may only be combined up to
a maximum of 15 ports, where a port-pair counts as two ports.
•Rules may only be combined until the length of
their concatenated comment reaches 255 characters.
When either of these limits would be exceeded, the current
combined rule is emitted and the compiler attempts 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'.
Beginning in Shorewall 4.5.10, this option also suppresses
duplicate adjacent rules and duplicate non-adjacent rules that don't include
mark, connmark, dscp, ecn, set,
tos or u32 matches.
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 result in the combined comment "Others and FOO,
BAR". Note: Optimize level 16 requires "Extended Multi-port
Match" in your iptables and kernel.
In versions prior to 5.1.0, the default value is zero which
disables all optimizations. Beginning with Shorewall 5.1.0, the default
value is All which enables 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.
PAGER=pathname
Added in Shorewall 5.0.6. Specifies a path name of a
pager program like
less or
more. When PAGER is given, the output
of verbose
status commands and the
dump command are piped
through the named program when the output file is a terminal.
Beginning with Shorewall 5.0.12, the default value of this option
is the DEFAULT_PAGER setting in shorewallrc.
PATH=pathname[:pathname]...
Determines the order in which Shorewall 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 Shorewall
falls back to /usr/bin/perl
PERL_HASH_SEED=seed|random
Added in Shorewall 5.1.4. Sets the Perl hash
seed
(an integer in the range 0-99999) when running the Shorewall rules compiler.
If not specified, the value 0 is assumed. If
random is specified, a
random seed will be chosed by Perl. See
perlsec(1) for additional
information.
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]If
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"
Earlier 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:
RSH_COMMAND
RCP_COMMAND
The default values for these are as follows:
RSH_COMMAND: ssh ${root}@${system} ${command}
RCP_COMMAND: scp ${files} ${root}@${system}:${destination}
Shell variables that will be set when the commands are invoked are
as follows:
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|CONTINUE]
Added in Shorewall 4.4.27. Shorewall has traditionally
ACCEPTed RELATED packets that don't match any rule in the RELATED section of
shorewall-rules[8] (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[:log-tag]
Added in Shorewall 4.4.27. Packets in the related state
that do not match any rule in the RELATED section of shorewall-rules[8]
(5) are logged at this level. The default value is empty which means no
logging is performed.
REJECT_ACTION=action
Added in Shorewall 4.5.21. When a REJECT target is
specified, Shorewall normally handles the response as follows:
•If the destination address of the packet is a
broadcast or multicast address, the packet is dropped.
•if the protocol is ICMP (2) then the packet is
dropped.
•if the protocol is TCP (6) then the packet is
rejected with an RST.
•if the protocol is UDP (17) then the packet is
rejected with an 'port-unreachable' ICMP.
•if the protocol is ICMP (1) then the packet is
rejected with a 'host-unreachable' ICMP.
•if the protocol is ICMP6 (1) then the packet is
rejected with a 'icmp6-addr-unreachable' ICMP6.
•otherwise, the packet is rejected with a
'host-prohibited' ICMP.
You can modify this behavior by implementing your own
action that handles REJECT and specifying it's name in this option.
The nolog and noinline options will automatically be assumed
for the specified action.
The following action implements the default reject action:
?format 2
#TARGET SOURCE DEST PROTO
Broadcast(DROP) - - -
DROP - - 2
INLINE - - 6 ;; -j REJECT --reject-with tcp-reset
?if __ENHANCED_REJECT
INLINE - - 17 ;; -j REJECT
?if __IPV4
INLINE - - 1 ;; -j REJECT --reject-with icmp-host-unreachable
INLINE - - - ;; -j REJECT --reject-with icmp-host-prohibited
?else
INLINE - - 58 ;; -j REJECT --reject-with icmp6-addr-unreachable
INLINE - - - ;; -j REJECT --reject-with icmp6-adm-prohibited
?endif
?else
INLINE - - - ;; -j REJECT
?endif
RENAME_COMBINED=[Yes|No]
Added in Shorewall 5.2.0. Traditionally, when OPTIMIZE
category 8 is enabled, identical chains are combined under a name beginning
with '~comb' or '~blacklist'. This behavior is maintained under the default
setting RENAME_COMBINED=Yes. If RENAMED_COMBINED=No, the chains are combined
under the original name of one of the chains.
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[25].
RESTART=[restart|reload]
Added in Shorewall 5.0.1 to replace LEGACY_RESTART which
was added in Shorewall 5.0.0. In that release, the reload command was
redefined to do what restart had done in earlier releases and
restart became a true restart (equivalent to stop followed by
start). When RESTART=reload, the restart command performs the
same operation as the reload command making it compatible with earlier
releases. If not specified, RESTART=reload is assumed.
RESTORE_DEFAULT_ROUTE=[Yes|No]
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.
RESTORE_ROUTEMARKS=[Yes|No]
Added in Shorewall 4.5.9. When set to Yes (the
default), provider marks are restored unconditionally at the top of the mangle
OUTPUT and PREROUTING chains, even if the saved mark is zero. When this option
is set to No, the mark is restored only if it is non-zero. If you have
problems with IPSEC ESP packets not being routed correctly on output, try
setting this option to No.
RESTOREFILE=filename
Specifies the simple name of a file in /var/lib/shorewall
to be used as the default restore script in the shorewall [-6] save,
shorewall [-6] restore, shorewall [-6] forget and shorewall
[6] -f start commands.
RETAIN_ALIASES={Yes|No}
IPv4 only.
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[3](5) and shorewall-masq[4](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, shorewall reload or shorewall restart.
ROUTE_FILTER=[Yes|No|Keep]
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 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[20](5).
Important
If you need to disable route filtering on any interface, then you must set
ROUTE_FILTER=No then set routefilter=1 or routefilter=2 on those interfaces
where you want route filtering. See
shorewall-interfaces[20](5) for
additional details.
RPFILTER_DISPOSITION=[DROP|REJECT|A_DROP|A_REJECT]
Added in Shorewall 4.5.7. Determines the disposition of
packets entering from interfaces the rpfilter option (see
shorewall-interfaces[20](5)). Packets disposed of by this option are
those whose response packets would not be sent through the same interface
receiving the packet.
RPFILTER_LOG_LEVEL=log-level[:log-tag]
Added in shorewall 4.5.7. Determines the logging of
packets disposed via the RPFILTER_DISPOSITION. The default value is
info.
SAVE_ARPTABLES={Yes|No}
Added in Shorewall 4.5.12. If SAVE_ARPTABLES=Yes, then
the current arptables contents will be saved by shorewall save command
and restored by shorewall restore command. Default value is No.
SAVE_IPSETS={Yes|No|ipv4|setlist}
Re-enabled in Shorewall 4.4.6. If SAVE_IPSETS=Yes, then
the current contents of your ipsets will be saved by the
shorewall stop
and
shorewall save commands and restored by the
shorewall start
and
shorewall restore commands.
Beginning with Shorewall 4.6.4, you can restrict the set of ipsets
saved by specifying a setlist (a comma-separated list of ipv4 ipset names).
You may also restrict the saved sets to just the ipv4 ones by specifying
ipv4.
SFILTER_DISPOSITION=[DROP|REJECT|A_DROP|A_REJECT]
Added in Shorewall 4.4.20. Determines the disposition of
packets matching the sfilter option (see
shorewall-interfaces[20](5)) and of hairpin packets on interfaces
without the routeback option.[26]
SFILTER_LOG_LEVEL=log-level[:log-tag]
Added on Shorewall 4.4.20. Determines the logging of
packets matching the sfilter option (see
shorewall-interfaces[20](5)) and of hairpin packets on interfaces
without the routeback option.[27] The default is info. If you
don't wish for these packets to be logged, use SFILTER_LOG_LEVEL=none.
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[20](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 iptables.
SMURF_LOG_LEVEL=[log-level[:log-tag]]
Specifies the logging level for smurf packets (see the
nosmurfs option in shorewall-interfaces[20](5)). If set to the empty
value ( SMURF_LOG_LEVEL="" ) then smurfs are not logged.
STARTUP_ENABLED={Yes|No}
Determines if Shorewall is allowed to start. As released
from shorewall.net, 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.
STARTUP_LOG=[pathname]
If specified, determines where Shorewall will log the
details of each start, reload, restart, try, and
safe-* 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 Shorewall to work with your
distribution's initscripts. For OpenSuSE, this should be set to
/var/lock/subsys/shorewall (var/lock/subsys/shorewall-lite if building for
export). For Gentoo, it should be set to /run/lock/shorewall
(/run/lock/shorewall-lite). For Redhat and derivatives as well as Debian and
derivatives, the pathname should be omitted.
Important
Beginning with Shorewall 5.1.0, this setting is ignored when SERVICEDIR is
non-empty in ${SHAREDIR}/shorewall/shorewallrc (usually
/usr/share/shorewall/shorewallrc).
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]
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|Simple|Shared]
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=Simple (Shorewall 4.4.6 and later), simple
traffic shaping using shorewall-tcinterfaces[28](5) and
shorewall-tcpri[29](5) is 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.
Beginning with Shorewall 4.4.15, you can set TC_ENABLED=Shared.
This allows you to configure the tcdevices and tcclasses in your Shorewall6
configuration yet make them available to the compiler when compiling your
Shorewall configuration. In addition to setting TC_ENABLED=Shared, you need
to create symbolic links from your Shorewall configuration directory
(normally /etc/shorewall/) to the tcdevices and tcclasses files in your
Shorewall6 configuration directory (normally /etc/shorewall6/).
TC_EXPERT={Yes|No}
Normally, Shorewall tries to protect users from
themselves by preventing PREROUTING and OUTPUT tcrules from being applied to
packets that have been marked by the 'track' option in
shorewall-providers[9](5).
If you know what you are doing, you can set TC_EXPERT=Yes and
Shorewall 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
shorewall-tcpri[29](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|A_DROP|A_REJECT]
Determines the disposition of TCP packets that fail the
checks enabled by the
tcpflags interface option (see
shorewall-interfaces[20](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.
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 iptables.
TCP_FLAGS_LOG_LEVEL=[log-level[:log-tag]]
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
shorewall-providers[9](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 shorewall-tcrules[12](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 rtrules 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.
TRACK_RULES={Yes|No|File}
Added in Shorewall 4.5.20. If set to
Yes, causes
the compiler to add a comment to iptables rules to indicate the file name and
line number of the configuration entry that generated the rule. If set to
No (the default), then no such comments are added.
Setting this option to Yes requires the Comments capability
in iptables and kernel.
Beginning with Shorewall 5.0.5, the option may also be set to
File. That setting causes similar comments to be added to the
.iptables-restore-input file, which is normally created in
/var/lib/shorewall.
UNTRACKED_DISPOSITION=[ACCEPT|A_ACCEPT|A_DROP|A_REJECT|DROP|REJECT|CONTINUE]
Added in Shorewall 4.5.13. Shorewall has traditionally
passed UNTRACKED packets through the NEW section of shorewall-rules[8]
(5). When a packet in UNTRACKED state fails to match any rule in the UNTRACKED
section, the packet is disposed of based on this setting. The default value is
CONTINUE for compatibility with earlier versions.
UNTRACKED_LOG_LEVEL=log-level[:log-tag]
Added in Shorewall 4.5.13. Packets in the UNTRACKED state
that do not match any rule in the UNTRACKED section of
shorewall-rules[8] (5) are logged at this level. The default value is
empty which means no logging is performed.
USE_DEFAULT_RT=[Yes|No]
When set to 'Yes', this option causes the Shorewall
multi-ISP feature to create a 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 default.
When USE_DEFAULT_RT=Yes:
1.Both the DUPLICATE and the COPY columns in
providers[9](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.If running Shorewall 5.1.0 or earlier or if
BALANCE_PROVIDERS=Yes (Shorewall 5.1.1 or later), then the balance
provider option is assumed unless the fallback, loose,
load or tproxy option is specified.
4.Packets are sent through the main routing table by a
rule with priority 999. In shorewall-rtrules[30](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..if n .sp
Note
detect may be specified for interfaces whose configuration is managed by
dhcpcd. Shorewall will use dhcpcd's database to find the interface'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).
Prior to Shorewall 4.6.0, if USE_DEFAULT_RT was not set or if it
was set to the empty string then USE_DEFAULT_RT=No was assumed. Beginning
with Shorewall 4.6.0, the default is USE_DEFAULT_RT=Yes and use of
USE_DEFAULT_RT=No is deprecated.
Warning
The
enable,
disable and
reenable commands do not work
correctly when USE_DEFAULT_RT=No.
USE_NFLOG_SIZE=[Yes|No]
Added in Shorewall 5.1.5. The second parameter to the
NFLOG target specifies how many bytes of the packet to copy to the log; if
omitted or if supplied as zero, the entire packet is copied. This feature has
traditionally been implemented using the --nflog-range option to the NFLOG
iptables target. Unfortuntely, the --nflog-range option never worked (the
entire packet was always copied). To deal with this issue, the Netfilter team:
•Added a warning message when --nflog-range is
used
•Added --nflog-size which works like --nflog-range
was intended to work.
When USE_NFLOG_SIZE=Yes, Shorewall will attempt to use the new
--nflog-size feature. If that feature is not available in the running kernel
and ip[6]tables, an error is raised.
When USE_NFLOG_SIZE is not supplied, USE_NFLOG_SIZE=No is assumed.
When USE_NFLOG_SIZE is added by shorewall update, it is added with setting
No.
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
interface'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.
USE_RT_NAMES=[Yes|No]
Added in Shorewall 4.5.15. When set to 'Yes', Shorewall
will use routing table (provider) names in the generated script rather than
table numbers. When set to 'No' (the default), routing table numbers will be
used.
Caution
If you set USE_RT_NAMES=Yes and KEEP_RT_TABLES=Yes, then you must insure that
all of your providers have entries in /etc/iproute2/rt_tables as well as the
following entries:
255 local
254 main
253 default
250 balance
0 unspec
Without these entries, the firewall will fail to start.
VERBOSE_MESSAGES=[Yes|No]
Added in Shorewall 5.0.9. When Yes (the default),
messages produced by the ?INFO and ?WARNING directives include the filename
and linenumber of the directive. When set to No, that additional information
is omitted. The setting may be overridden on a directive by directive basis by
following ?INFO or ?WARNING with '!' (no intervening white space).
VERBOSITY=[number]
Shorewall 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 Shorewall-3.2.0
behavior)
If not specified, then 2 is assumed.
WARNOLDCAPVERSION=[Yes|No]
Added in Shorewall 4.5.12. When set to Yes (the
default), the compiler issues a warning when it finds a capabilities file that
doesn't specify all of the capabilities supported by the compiler. When
WARNOLDCAPVERSION is set to No, no warning is issued.
WORKAROUNDS=[Yes|No]
Added in Shorewall 4.6.11. Over time, there have been a
number of changes in Shorewall that work around defects in other products such
as iptables and ipset. When WORKAROUNDS=Yes, these workarounds are enabled;
when WORKAROUNDS=No, they are disabled. If not specified or if specified as
empty, WORKAROUNDS=Yes is assumed.
Warning
Do not set WORKAROUNDS=Yes if you need to be able to use Shorewall-generated
scripts (such as created by the
save command) built by Shorewall 4.4.7
or older.
ZERO_MARKS=[Yes|No]
Added in Shorewall 5.0.12, this is a workaround for an
issue where packet marks are not zeroed by the kernel. It should be set to No
(the default) unless you find that incoming packets are being mis-routed for
no apparent reasons.
Caution
Do not set this option to Yes if you have IPSEC software running on the firewall
system.
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'. Beginning
with Shorewall 4.6.0, the default is '-' (e.g., fw-net); prior to that
release, the default was '2' (e.g., fw2net).