SHOREWALL.CONF(5)SHOREWALL.CONF(5)NAMEshorewall.conf - Shorewall global configuration file
SYNOPSIS
/etc/shorewall/shorewall.conf
DESCRIPTION
This file sets options that apply to Shorewall as a whole.
The file consists of Shell comments (lines beginning with ´#´), blank
lines and assignment statements (variable=value). If the value contains
shell metacharacters or white-space, then it must be enclosed in
quotes. Example: MACLIST_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 Shorewall also uses that term.
Valid levels are:
7 debug
6 info
5 notice
4 warning
3 err
2 crit
1 alert
0 emerg
For most Shorewall logging, a level of 6 (info) is appropriate.
Shorewall log messages are generated by NetFilter and are logged using
facility ´kern´ and the level that you specifify. If you are unsure of
the level to choose, 6 (info) is a safe bet. You may specify levels by
name or by number.
If you have built your kernel with ULOG and/or NFLOG target support,
you may also specify a log level of ULOG and/or NFLOG (must be all
caps). Rather than log its messages to syslogd, Shorewall will direct
netfilter to log the messages via the ULOG or NFLOG target which will
send them to a process called ´ulogd´. ulogd is available with most
Linux distributions (although it probably isn´t installed by default).
Ulogd is also available from
http://www.netfilter.org/projects/ulogd/index.html and can be
configured to log all Shorewall messages to their own log file
The following options may be set in shorewall.conf.
ACCEPT_DEFAULT={action|macro|none}
DROP_DEFAULT={action|macro|none}
REJECT_DEFAULT={action|macro|none}
QUEUE_DEFAULT={action|macro|none}
NFQUEUE_DEFAULT={action|macro|none}
In earlier Shorewall versions, a "default action" for DROP and
REJECT policies was specified in the file
/usr/share/shorewall/actions.std.
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) 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 shorewall-policy[1](5).
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.
ADD_IP_ALIASES=[Yes|No]
This parameter determines whether Shorewall automatically adds the
external address(es) in shorewall-nat[3](5). If the variable is set
to Yes or yes then Shorewall automatically adds these aliases. If
it is set to No or no, you must add these aliases yourself using
your distribution´s network configuration tools.
If this variable is not set or is given an empty value
(ADD_IP_ALIASES="") then ADD_IP_ALIASES=Yes is assumed.
Warning
Addresses added by ADD_IP_ALIASES=Yes are deleted and re-added
during shorewall restart. As a consequence, connections using those
addresses may be severed.
ADD_SNAT_ALIASES=[Yes|No]
This parameter determines whether Shorewall automatically adds the
SNAT ADDRESS in shorewall-masq[4](5). If the variable is set to Yes
or yes then Shorewall automatically adds these addresses. If it is
set to No or no, you must add these addresses yourself using your
distribution´s network configuration tools.
If this variable is not set or is given an empty value
(ADD_SNAT_ALIASES="") then ADD_SNAT_ALIASES=No is assumed.
Warning
Addresses added by ADD_SNAT_ALIASES=Yes are deleted and re-added
during shorewall restart. As a consequence, connections using those
addresses may be severed.
ADMINISABSENTMINDED=[Yes|No]
The value of this variable affects Shorewall´s stopped state. When
ADMINISABSENTMINDED=No, only traffic to/from those addresses listed
in shorewall-routestopped[5](5) is accepted when Shorewall is
stopped. When ADMINISABSENTMINDED=Yes, in addition to traffic
to/from addresses in shorewall-routestopped[5](5), connections that
were active when Shorewall stopped continue to work and all new
connections from the firewall system itself are allowed. If this
variable is not set or is given the empty value then
ADMINISABSENTMINDED=No is assumed.
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´.
The setting of the AUTOMAKE option is ignored if the start or
restart command includes a directory name (e.g., shorewall restart
/etc/shorewall.new).
AUTOMAKE=[Yes|No]
If set, the behavior of the ´start´ command is changed; 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.
BIGDPORTLISTS=[Yes|No]
Setting this option to ´Yes´ allows you to include arbitrarily long
destination port lists in all configuration files.
BLACKLIST_DISPOSITION=[DROP|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.
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.
BLACKLISTNEWONLY={Yes|No}
When set to Yes or yes, blacklists are only consulted for new
connections. When set to No or no, blacklists are consulted for
every packet (will slow down your firewall noticably if you have
large blacklists). If the BLACKLISTNEWONLY option is not set or is
set to the empty value then BLACKLISTNEWONLY=No is assumed.
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 Shorewall won´t clear the current
traffic control rules during [re]start. 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[6](5). If not specified, CLEAR_TC=Yes is assumed.
CONFIG_PATH=[directory[:directory]...]
Specifies where configuration files other than shorewall.conf may
be found. CONFIG_PATH is specifies as a list of directory names
separated by colons (":"). When looking for a configuration file
other than shorewall.conf:
· If the command is "try" or a "<configuration directory>" was
specified in the command (e.g., shorewall check ./gateway) then
the directory given in the command is searched first.
· Next, each directory in the CONFIG_PATH setting is searched in
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.
Note that the setting in /usr/share/shorewall/configpath is
always used to locate shorewall.conf.
DELETE_THEN_ADD={Yes|No}
If set to Yes (the default value), entries in the
/etc/shorewall/route_stopped files cause an ´ip rule del´ command
to be generated in addition to an ´ip rule add´ command. Setting
this option to No, causes the ´ip rule del´ command to be omitted.
DETECT_DNAT_IPADDRS=[Yes|No]
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]
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.
DONT_LOAD=[module[,module]...]
Causes Shorewall 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 shorewall drop, shorewall reject, shorewall
logdrop and shorewall 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.
EXPORTPARAMS={Yes|No}
It is quite difficult to code a ´params´ file that assigns other
than constant values such that it works correctly with Shorewall
Lite. The EXPORTPARAMS option works around this problem. When
EXPORTPARAMS=No, the ´params´ file is not copied to the compiler
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 using Shorewall Lite.
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
´loc2net´ chain.
If you set FASTACCEPT=Yes, then ESTABLISHED/RELEATED packets are
accepted early in the INPUT, FORWARD and OUTPUT chains. If you set
FASTACCEPT=Yes then you may not include rules in the ESTABLISHED or
RELATED sections of shorewall-rules[7](5).
Note
FASTACCEPT=Yes is incompatible with BLACKLISTNEWONLY=No.
HIGH_ROUTE_MARKS={Yes|No}
Prior to version 3.2.0, it was not possible to use connection
marking in shorewall-tcrules[6](5) if you had a multi-ISP
configuration that uses the track option.
You may set HIGH_ROUTE_MARKS=Yes in to effectively divide the
packet mark and connection mark into two mark fields.
Note
From Shorewall 2.5.0 onward, this option is deprecated in favor of
the PROVIDER_OFFSET option.
The width of the fields are determined by the setting of
WIDE_TC_MARKS. If 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 shorewall-zones[8](5)). Normally, you want to have
a set of special rules for the subzone and if a connection doesn´t
match any of those subzone-specific rules then you want the parent
zone rules and policies to be applied; see shorewall-nesting[9](5).
With IMPLICIT_CONTINUE=Yes, that happens automatically.
If IMPLICIT_CONTINUE=No or if IMPLICIT_CONTINUE is not set, then
subzones are not subject to this special treatment. With
IMPLICIT_CONTINUE=Yes, an implicit CONTINUE policy may be
overridden by including an explicit policy (one that does not
specify "all" in either the SOURCE or the DEST columns).
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 parameter determines whether Shorewall enables or disables
IPV4 Packet Forwarding (/proc/sys/net/ipv4/ip_forward). Possible
values are:
On or on
packet forwarding will be enabled.
Off or off
packet forwarding will be disabled.
Keep or keep
Shorewall will neither enable nor disable packet forwarding.
If this variable is not set or is given an empty value
(IP_FORWARD="") then IP_FORWARD=On is assumed.
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.
IPTABLES=[pathname]
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.
KEEP_RT_TABLES={Yes|No}
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, refresh,
restore on restart command.
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/helpers and those that are actually used. When
not set, or set to the empty value, LOAD_HELPERS_ONLY=No is
assumed.
LOG_MARTIANS=[Yes|No|Keep]
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[10](5).
The value Keep causes Shorewall to ignore the option. If the option
is set to Yes, then martians are logged on all interfaces. If the
option is set to No, then martian logging is disabled on all
interfaces except those specified in shorewall-interfaces[10](5).
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:
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/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
http://www.shorewall.net/shorewall_logging.html.
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.
LOGBURST=[burst]
LOGRATE=[rate/{minute|second}]
These parameters set the match rate and initial burst size for
logged packets. Please see iptables(8) for a description of the
behavior of these parameters (the iptables option --limit is set by
LOGRATE and --limit-burst is set by LOGBURST). If both parameters
are set empty, no rate-limiting will occur. 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]
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.
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[11](5) can be improved by setting the
MACLIST_TTL variable in shorewall.conf[12](5).
If your iptables and kernel support the "Recent Match" (see the
output of "shorewall check" near the top), you can cache the
results of a ´maclist´ file lookup and thus reduce the overhead
associated with MAC Verification.
When a new connection arrives from a ´maclist´ interface, the
packet passes through then list of entries for that interface in
shorewall-maclist[11](5). If there is a match then the source IP
address is added to the ´Recent´ set for that interface. Subsequent
connection attempts from that IP address occurring within
$MACLIST_TTL seconds will be accepted without having to scan all of
the entries. After $MACLIST_TTL from the first accepted connection
request from an IP address, the next connection request from that
IP address will be checked against the entire list.
If MACLIST_TTL is not specified or is specified as empty (e.g,
MACLIST_TTL="" or is specified as zero then ´maclist´ lookups will
not be cached).
MAPOLDACTIONS=[Yes|No]
This option is included for compatibility with old Shorewall
configuration. New installs should always have MAPOLDACTIONS=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
/sbin/shorewall show mangle command; if a FORWARD chain is
displayed then your kernel will support this option. If this option
is not specified or if it is given the empty value (e.g.,
MARK_IN_FORWARD_CHAIN="") then MARK_IN_FORWARD_CHAIN=No is assumed.
MODULE_SUFFIX=["extension ..."]
The value of this option determines the possible file extensions of
kernel modules. The default value is "o gz ko o.gz".
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
-r`/kernel/net/ipv4/netfilter" in versions of Shorewall prior to
3.2.4 and "/lib/modules/`uname
-r`/kernel/net/ipv4/netfilter:/lib/modules/`uname
-r`/kernel/net/ipv4/netfilter" in later versions.
MULTICAST=[Yes|No]
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 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
restart command.
NULL_ROUTE_RFC1918=[Yes|No]
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[10](5)), this option ensures that packets
with an RFC1918 source address are only accepted from interfaces
having known routes to networks using such addresses.
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.
· Optimization category 1 - Traditionally, Shorewall has created
rules for the complete matrix of host groups defined by the
zones, interfaces and hosts files[13]. Any traffic that didn´t
correspond to an element of that matrix was rejected in one of
the built-in chains. When the matrix is sparse, this results in
lots of largely useless rules.
These extra rules can be eliminated by setting 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.
· 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.
· 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.
· Optimization category 8 - Added in Shorewall 4.4.9. When set,
causes chains with duplicate rules to be collapsed into a
single chain.
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 Shorewall searches directories for
executable files.
PKTTYPE={Yes|No}
This option is included for compatibility with older Shorewall
releases. Its setting has no effect.
RCP_COMMAND="command"
RSH_COMMAND="command"
Eariler generations of Shorewall Lite required that remote root
login via ssh be enabled in order to use the load and reload
commands. Beginning with release 3.9.5, you may define an
alternative means for accessing the remote firewall system. In that
release, two new options were added to shorewall.conf:.IP "" 4
RSH_COMMAND
RCP_COMMAND The default values for these are as follows:.IP ""
4 RSH_COMMAND: ssh ${root}@${system} ${command}
RCP_COMMAND: scp ${files}
${root}@${system}:${destination} Shell variables
that will be set when the commands are envoked are as
follows:.IP "" 4 root - root user. Normally
root but may be overridden using the ´-r´
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.
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.
RESTOREFILE=filename
Specifies the simple name of a file in /var/lib/shorewall to be
used as the default restore script in the shorewall save, shorewall
restore, shorewall forget and shorewall -f start commands.
RETAIN_ALIASES={Yes|No}
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 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[10](5).
SAVE_IPSETS={Yes|No}
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.
SHOREWALL_SHELL=[pathname]
This option is used to specify the shell program to be used to run
the Shorewall compiler and to interpret the compiled script. If not
specified or specified as a null value, /bin/sh is assumed. Using a
light-weight shell such as ash or dash can significantly improve
performance.
SMURF_LOG_LEVEL=[log-level]
Specifies the logging level for smurf packets (see the nosmurfs
option in shorewall-interfaces[10](5)). If set to the empty value (
SMURF_LOG_LEVEL="" ) then smurfs are not logged.
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, 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 Shorewall to work
with your distribution´s initscripts. For RedHat and OpenSuSE, this
should be set to /var/lock/subsys/shorewall. For Debian, the value
is /var/lock/shorewall and in LEAF it is /var/run/shorwall.
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_ENABLED=[Yes|No|Internal|Simple]
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[14](5) and
shorewall-tcpri[15](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.
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[16](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[15](5). The map
consists of 16 space-separated digits with values 1, 2 or 3. The
first entry corresponds to Linux priority 9, the second to Linux
priority 1, the third to Linux Priority 2, 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
shorewall-interfaces[10](5)) and must have a value of ACCEPT
(accept the packet), REJECT (send an RST response) or DROP (ignore
the packet). If not set or if set to the empty value (e.g.,
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
shorewall-providers[16](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[6](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 route_rules 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]
When set to ´Yes´, this option causes the Shorewall multi-ISP
feature to create a different set of routing rules which are
resilient to changes in the main routing table. Such changes can
occur for a number of reasons, VPNs going up and down being an
example. The idea is to send packets through the main table prior
to applying any of the Shorewall-generated routing rules. So
changes to the main table will affect the routing of packets by
default.
When USE_DEFAULT_RT=Yes:
1. Both the DUPLICATE and the COPY columns in providers[16](5)
file must remain empty (or contain "-").
2. The default route is added to the the ´default´ table rather
than to the main table.
3. balance is assumed unless loose is specified.
4. Packets are sent through the main routing table by a rule with
priority 999. In routing_rules[17](5), the range 1-998 may be
used for inserting rules that bypass the main table.
5. All provider gateways must be specified explicitly in the
GATEWAY column. detect may not be specified..sp
Note
detect may be specified for interfaces whose configuration is
managed by dhcpcd. Shorewall will use dhcpcd´s database to find
the interfaces´s gateway.
6. You should disable all default route management outside of
Shorewall. If a default route is added to the main table while
Shorewall is started, then all policy routing will stop working
(except for those routing rules in the priority range 1-998).
If USE_DEFAULT_RT is not set or if it is set to the empty
string then USE_DEFAULT_RT=No is assumed.
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.
WIDE_TC_MARKS={Yes|No}
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).
Note
From Shorewall 2.5.0 onware, this option is deprecated in favor of
the TC_BITS option.
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/shorewall/shorewall.conf
SEE ALSOshorewall(8), shorewall-accounting(5), shorewall-actions(5),
shorewall-blacklist(5), shorewall-hosts(5), shorewall-interfaces(5),
shorewall-ipsec(5), shorewall-maclist(5), shorewall-masq(5),
shorewall-nat(5), shorewall-netmap(5), shorewall-params(5),
shorewall-policy(5), shorewall-providers(5), shorewall-proxyarp(5),
shorewall-route_rules(5), shorewall-routestopped(5),
shorewall-rules(5), shorewall-tcclasses(5), shorewall-tcdevices(5),
shorewall-tcinterfaces(5), shorewall-tcpri(5), shorewall-tcrules(5),
shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)NOTES
1. shorewall-policy
shorewall-policy.html
2. shorewall-accounting
shorewall-accounting.html
3. shorewall-nat
shorewall-nat.html
4. shorewall-masq
shorewall-masq.html
5. shorewall-routestopped
shorewall-routestopped.html
6. shorewall-tcrules
shorewall-tcrules.html
7. shorewall-rules
shorewall-rules.html
8. shorewall-zones
shorewall-zones.html
9. shorewall-nesting
shorewall-nesting.html
10. shorewall-interfaces
shorewall-interfaces.html
11. shorewall-maclist
shorewall-maclist.html
12. shorewall.conf
shorewall.conf.html
13. the complete matrix of host groups defined by the zones, interfaces
and hosts files
../ScalabilityAndPerformance.html
14. shorewall-tcinterfaces
shorewall-tcinterfaces.html
15. shorewall-tcpri
shorewall-tcpri.html
16. shorewall-providers
shorewall-providers.html
17. routing_rules
shorewall-routing_rules.html
05/07/2010 SHOREWALL.CONF(5)
