shorewall_code/STABLE2/shorewall.conf

##############################################################################
#  /etc/shorewall/shorewall.conf V2.2 - Change the following variables to
#  match your setup
#
#  This program is under GPL [http://www.gnu.org/copyleft/gpl.htm]
#
#  This file should be placed in /etc/shorewall
#
#  (c) 1999,2000,2001,2002,2003,2004 - Tom Eastep (teastep@shorewall.net)
##############################################################################
#                      S T A R T U P   E N A B L E D
##############################################################################
# Once you have configured Shorewall, you may change the setting of
# this variable to 'Yes'

STARTUP_ENABLED=No

##############################################################################
#                              L O G G I N G
##############################################################################
#
# General note about log levels. 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 target support, you may also
# specify a log level of ULOG (must be all caps). Rather than log its
# messages to syslogd, Shorewall will direct netfilter to log the messages
# via the ULOG target which will send them to a process called 'ulogd'.
# ulogd is available from http://www.gnumonks.org/projects/ulogd and can be
# configured to log all Shorewall message to their own log file
################################################################################
#
# LOG FILE LOCATION
#
# This variable tells the /sbin/shorewall program where to look for Shorewall
# log messages. If not set or set to an empty string (e.g., LOGFILE="") then
# /var/log/messages is assumed.
#
# WARNING: The LOGFILE variable simply tells the 'shorewall' program where to
#          look for Shorewall messages.It does NOT control the destination for
#          these messages. For information about how to do that, see
#
#              http://www.shorewall.net/shorewall_logging.html

LOGFILE=/var/log/messages

#
# LOG FORMAT
#
# Shell 'printf' Formatting template for the --log-prefix value in log messages
# generated by Shorewall to identify Shorewall log messages. The supplied
# template is expected to accept either two or three arguments; the first is
# the chain name, the second (optional) is the logging rule number within that
# chain and the third is the ACTION specifying the disposition of the packet
# being logged. You must use the %d formatting type for the rule number; if your
# template does not contain %d then the rule number will not be included.
#
# If you want to integrate Shorewall with fireparse, then set LOGFORMAT as:
#
#	LOGFORMAT="fp=%s:%d a=%s "
#
# If not specified or specified as empty (LOGFORMAT="") then the value
# "Shorewall:%s:%s:" is assumed.
# 
# CAUTION: /sbin/shorewall uses the leading part of the LOGFORMAT string (up 
# to but not including the first '%') to find log messages in the 'show log',
# 'status' and 'hits' commands. This part should not be omitted (the 
# LOGFORMAT should not begin with "%") and the leading part should be
# sufficiently unique for /sbin/shorewall to identify Shorewall messages.

LOGFORMAT="Shorewall:%s:%s:"

#
# LOG FORMAT Continued
#
# 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.
#

LOGTAGONLY=No

#
# LOG RATE LIMITING
#
# The next two variables can be used to control the amount of log output
# generated. LOGRATE is expressed as a number followed by an optional
# `/second',  `/minute', `/hour', or `/day' suffix and specifies the maximum
# rate at which a particular message will occur. LOGBURST determines the
# maximum initial burst size that will be logged. If set empty, the default
# value of 5 will be used.
#
# If BOTH variables are set empty then logging will not be rate-limited.
#
# 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 which passes without
# matching a packet, one of the bursts will be regained; if no packets hit
# the rule for 30 seconds, the burst will be fully recharged; back where
# we started.
#

LOGRATE=
LOGBURST=

#
# LOG ALL NEW
#
# This option should only be used when you are trying to analyze a problem.
# It causes all packets in the Netfilter NEW state to be logged as the 
# first rule in each builtin chain. To use this option, set LOGALLNEW to 
# the log level that you want these packets logged at (e.g.,
# LOGALLNEW=debug).
#

LOGALLNEW=

#
# BLACKLIST LOG LEVEL
#
# Set this variable to the syslogd level that you want blacklist packets logged
# (beware of DOS attacks resulting from such logging). If not set, no logging
# of blacklist packets occurs.
#
# See the comment at the top of this section for a description of log levels
#
BLACKLIST_LOGLEVEL=

#
# LOGGING 'New not SYN' rejects
#
# This variable only has an effect when NEWNOTSYN=No (see below).
#
# When a TCP packet that does not have the SYN flag set and the ACK and RST
# flags clear then unless the packet is part of an established connection,
# it will be rejected by the firewall. If you want these rejects logged,
# then set LOGNEWNOTSYN to the syslog log level at which you want them logged.
#
# See the comment at the top of this section for a description of log levels
#
# Example: LOGNEWNOTSYN=debug


LOGNEWNOTSYN=info

#
# MAC List Log Level
#
# Specifies the logging level for connection requests that fail MAC
# verification. If set to the empty value (MACLIST_LOG_LEVEL="") then
# such connection requests will not be logged.
#
# See the comment at the top of this section for a description of log levels
#

MACLIST_LOG_LEVEL=info

#
# TCP FLAGS Log Level
#
# Specifies the logging level for packets that fail TCP Flags
# verification. If set to the empty value (TCP_FLAGS_LOG_LEVEL="") then
# such packets will not be logged.
#
# See the comment at the top of this section for a description of log levels
#

TCP_FLAGS_LOG_LEVEL=info

#
# RFC1918 Log Level
#
# Specifies the logging level for packets that fail RFC 1918
# verification. If set to the empty value (RFC1918_LOG_LEVEL="") then
# RFC1918_LOG_LEVEL=info is assumed.
#
# See the comment at the top of this section for a description of log levels
#

RFC1918_LOG_LEVEL=info

#
# SMURF Log Level
#
# Specifies the logging level for smurf packets dropped by the
#'nosmurfs' interface option in /etc/shorewall/interfaces and in
# /etc/shorewall/hosts. If set to the empty value ( SMURF_LOG_LEVEL=""
# ) then dropped smurfs are not logged. 

#
# See the comment at the top of this section for a description of log levels
#

SMURF_LOG_LEVEL=info

#
# BOGON Log Level
#
# Specifies the logging level for bogon packets dropped by the
#'nobogons' interface option in /etc/shorewall/interfaces and in
# /etc/shorewall/hosts. If set to the empty value
# ( BOGON_LOG_LEVEL="" ) then packets whose TARGET is 'logdrop'
# in /usr/share/shorewall/bogons are logged at the 'info' level.
#
# See the comment at the top of this section for a description of log levels
#

BOGON_LOG_LEVEL=info

#
# MARTIAN LOGGING
#
# Setting LOG_MARTIANS=Yes will enable kernel logging of all received packets
# that have impossible source IP addresses. This logging may be enabled 
# on individual interfaces by using the 'logmartians' option in
# /etc/shorewall/interfaces.
#

LOG_MARTIANS=No
################################################################################
#       L O C A T I O N   O F   F I L E S   A N D   D I R E C T O R I E S
################################################################################
#
# IPTABLES
#
# Full path to iptables executable Shorewall uses to build the firewall. If 
# not specified or if specified with an empty value (e.g., IPTABLES="") then
# the iptables executable located via the PATH setting below is used.
#
IPTABLES=

#
# PATH - Change this if you want to change the order in which Shorewall
#        searches directories for executable files.
#
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:/usr/local/sbin

#
# SHELL
#
# The firewall script is normally interpreted by /bin/sh. If you wish to change
# the shell used to interpret that script, specify the shell here.

SHOREWALL_SHELL=/bin/sh

# SUBSYSTEM LOCK FILE
#
# Set this to the name of the lock file expected by your init scripts. For
# RedHat, this should be /var/lock/subsys/shorewall. If your init scripts don't
# use lock files, set this to "".
#

SUBSYSLOCK=/var/lock/subsys/shorewall

#
# SHOREWALL TEMPORARY STATE DIRECTORY
#
# This is the directory where the firewall maintains state information while
# it is running
#

STATEDIR=/var/lib/shorewall

#
# KERNEL MODULE DIRECTORY
#
# If your netfilter kernel modules are in a directory other than
# /lib/modules/$(uname -r)/kernel/net/ipv4/netfilter then specify that
# directory in this variable. Example: MODULESDIR=/etc/modules.

MODULESDIR=

#
# CONFIGURATION SEARCH PATH
#
# This option holds a list of directory names separated by colons
# (":"). Shorewall will search each directory in turn when looking for a
# configuration file. When processing a 'try' command or a command
# containing the "-c" option, Shorewall will automatically add the
# directory specified in the command to the front of this list.
#
# If not specified or specified as null ("CONFIG_PATH=""),
# CONFIG_PATH=/etc/shorewall:/usr/share/shorewall is assumed.

CONFIG_PATH=/etc/shorewall:/usr/share/shorewall

#
# RESTORE SCRIPT
#
# This option determines the script to be run in the following cases:
#
#	shorewall -f start
#	shorewall restore
#	shorewall save
#	shorewall forget
#	Failure of shorewall start or shorewall restart
#
# The value of the option must be the name of an executable file in the
# directory /var/lib/shorewall. If this option is not set or if it is
# set to the empty value (RESTOREFILE="") then RESTOREFILE=restore is
# assumed.

RESTOREFILE=
################################################################################
#                       F I R E W A L L   O P T I O N S
################################################################################

# NAME OF THE FIREWALL ZONE
#
# Name of the firewall zone -- if not set or if set to an empty string, "fw"
# is assumed.
#
FW=fw

#
# ENABLE IP FORWARDING
#
# If you say "On" or "on" here, IPV4 Packet Forwarding is enabled. If you
# say "Off" or "off", packet forwarding will be disabled. You would only want
# to disable packet forwarding if you are installing Shorewall on a
# standalone system or if you want all traffic through the Shorewall system
# to be handled by proxies.
#
# If you set this variable to "Keep" or "keep", Shorewall will neither
# enable nor disable packet forwarding.
#
IP_FORWARDING=On

#
# AUTOMATICALLY ADD NAT IP ADDRESSES
#
# If you say "Yes" or "yes" here, Shorewall will automatically add IP addresses
# for each NAT external address that you give in /etc/shorewall/nat. If you say
# "No" or "no", you must add these aliases youself.
#
ADD_IP_ALIASES=Yes

#
# AUTOMATICALLY ADD SNAT IP ADDRESSES
#
# If you say "Yes" or "yes" here, Shorewall will automatically add IP addresses
# for each SNAT external address that you give in /etc/shorewall/masq. If you say
# "No" or "no", you must add these aliases youself. LEAVE THIS SET TO "No" unless
# you are sure that you need it -- most people don't!!!
#
ADD_SNAT_ALIASES=No

#
# RETAIN EXISTING ALIASES/IP ADDRESSES
#
# Normally, when ADD_IP_ALIASES=Yes and/or ADD_SNAT_ALIASES=Yes then Shorewall
# will first delete the address then re-add it. This is to ensure that the
# address is added with the specified label. Unfortunately, this can cause
# problems if it results in the deletion of the last IP address on an
# interface because then all routes through the interface are automatically 
# removed.
#
# You can cause Shorewall to retain existing addresses by setting
# RETAIN_ALIASES=Yes. 
#
RETAIN_ALIASES=No

#
# ENABLE TRAFFIC SHAPING
#
# If you say "Yes" or "yes" here, Traffic Shaping is enabled in the firewall. If
# you say "No" or "no" then traffic shaping is not enabled. If you enable traffic
# shaping you must have iproute[2] installed (the "ip" and "tc" utilities) and
# you must enable packet mangling above.
#
TC_ENABLED=No

#
# Clear Traffic Shapping/Control
#
# If this option is set to 'No' then Shorewall won't clear the current
# traffic control rules during [re]start. This setting is intended
# for use by people that prefer to configure traffic shaping when
# the network interfaces come up rather than when the firewall
# is started. If that is what you want to do, set TC_ENABLED=Yes and
# CLEAR_TC=No and do not supply an /etc/shorewall/tcstart file. That
# way, your traffic shaping rules can still use the 'fwmark'
# classifier based on packet marking defined in /etc/shorewall/tcrules.
#
# If omitted, CLEAR_TC=Yes is assumed.

CLEAR_TC=Yes

#
# Mark Packets in the forward chain
#
# When processing the tcrules file, Shorewall normally marks packets in the
# PREROUTING chain. To cause Shorewall to use the FORWARD chain instead, set
# this to "Yes". If not specified or if set to the empty value (e.g.,
# MARK_IN_FORWARD_CHAIN="") then MARK_IN_FORWARD_CHAIN=No is assumed.
#
# Marking packets in the FORWARD chain has the advantage that inbound
# packets destined for Masqueraded/SNATed local hosts have had their destination
# address rewritten so they can be marked based on their destination. When
# packets are marked in the PREROUTING chain, packets destined for
# Masqueraded/SNATed local hosts still have a destination address corresponding
# to the firewall's external interface.
#
# Note: Older kernels do not support marking packets in the FORWARD chain and
#       setting this variable to Yes may cause startup problems.

MARK_IN_FORWARD_CHAIN=No

#
# MSS CLAMPING
#
# Set this variable to "Yes" or "yes" if you want the TCP "Clamp MSS to PMTU"
# option. This option is most commonly required when your internet
# interface is some variant of PPP (PPTP or PPPoE). Your kernel must
# have CONFIG_IP_NF_TARGET_TCPMSS set.
#
# [From the kernel help:
#
#    This option adds a `TCPMSS' target, which allows you to alter the
#    MSS value of TCP SYN packets, to control the maximum size for that
#    connection (usually limiting it to your outgoing interface's MTU
#    minus 40).
#
#    This is used to overcome criminally braindead ISPs or servers which
#    block ICMP Fragmentation Needed packets.  The symptoms of this
#    problem are that everything works fine from your Linux
#    firewall/router, but machines behind it can never exchange large
#    packets:
#        1) Web browsers connect, then hang with no data received.
#	 2) Small mail works fine, but large emails hang.
#	 3) ssh works fine, but scp hangs after initial handshaking.
# ]
#
# If left blank, or set to "No" or "no", the option is not enabled.
#
# You may also set this option to a numeric value in which case Shorewall will
# set up a rule to modify the MSS value in SYN packets to the value that
# you specify.
#
# Example:
#
#	CLAMPMSS=1400
#
CLAMPMSS=No

#
# ROUTE FILTERING
#
# Set this variable to "Yes" or "yes" if you want kernel route filtering on all
# interfaces started while Shorewall is started (anti-spoofing measure).
#
# If this variable is not set or is set to the empty value, "No" is assumed.
# Regardless of the setting of ROUTE_FILTER, you can still enable route filtering
# on individual interfaces using the 'routefilter' option in the
# /etc/shorewall/interfaces file.

ROUTE_FILTER=No

# DNAT IP ADDRESS DETECTION
#
# Normally when Shorewall encounters the following rule:
#
#	DNAT	net	loc:192.168.1.3	tcp	80
#
# it will forward TCP port 80 connections from the net to 192.168.1.3
# REGARDLESS OF THE ORIGINAL DESTINATION ADDRESS. This behavior is
# convenient for two reasons:
#
#	a) If the the network interface has a dynamic IP address, the
#	   firewall configuration will work even when the address
#	   changes.
#
#	b) It saves having to configure the IP address in the rule
#	   while still allowing the firewall to be started before the
#	   internet interface is brought up.
#
# This default behavior can also have a negative effect. If the
# internet interface has more than one IP address then the above
# rule will forward connection requests on all of these addresses;
# that may not be what is desired.
#
# By setting DETECT_DNAT_IPADDRS=Yes, rules such as the above will apply
# only if the original destination address is the primary IP address of
# one of the interfaces associated with the source zone. Note that this
# requires all interfaces to the source zone to be up when the firewall
# is [re]started.

DETECT_DNAT_IPADDRS=No

#
# MUTEX TIMEOUT
#
# 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.

MUTEX_TIMEOUT=60

#
# NEWNOTSYN
#
# TCP connections are established using the familiar three-way "handshake":
#
#	CLIENT			SERVER
#
#	SYN-------------------->
#            <------------------SYN,ACK
#       ACK-------------------->
#
# The first packet in that exchange (packet with the SYN flag on and the ACK
# and RST flags off) is referred to in Netfilter terminology as a "syn" packet.
# A packet is said to be NEW if it is not part of or related to an already
# established connection.
#
# The NEWNOTSYN option determines the handling of non-SYN packets (those with
# SYN off or with ACK or RST on) that are not associated with an already
# established connection.
# 
# If NEWNOTSYN is set to "No" or "no", then non-SYN packets that are not
# part of an already established connection will be dropped by the
# firewall. The setting of LOGNEWNOTSYN above determines if these packets are
# logged before they are dropped.
#
# If NEWNOTSYN is set to "Yes" or "yes" then such packets will not be
# dropped but will pass through the normal rule/policy processing.
#
# Users with a High-availability setup with two firewall's and one acting
# as a backup should set NEWNOTSYN=Yes. Users with asymmetric routing may
# also need to select NEWNOTSYN=Yes.
#
# The behavior of NEWNOTSYN=Yes may also be enabled on a per-interface basis 
# using the 'newnotsyn' option in /etc/shorewall/interfaces and on a
# network or host basis using the same option in /etc/shorewall/hosts.

#
# I find that NEWNOTSYN=No tends to result in lots of "stuck"
# connections because any network timeout during TCP session tear down
# results in retries being dropped (Netfilter has removed the
# connection from the conntrack table but the end-points haven't
# completed shutting down the connection).  I therefore have chosen
# NEWNOTSYN=Yes as the default value.

NEWNOTSYN=Yes

#
# FOR ADMINS THAT REPEATEDLY SHOOT THEMSELVES IN THE FOOT
#
# Normally, when a "shorewall stop" command is issued or an error occurs during
# the execution of another shorewall command, Shorewall puts the firewall into
# a state where only traffic to/from the hosts listed in
# /etc/shorewall/routestopped is accepted. 
#
# When performing remote administration on a Shorewall firewall, it is
# therefore recommended that the IP address of the computer being used for
# administration be added to the firewall's /etc/shorewall/routestopped file.
#
# Some administrators have a hard time remembering to do this with the result
# that they get to drive across town in the middle of the night to restart
# a remote firewall (or worse, they have to get someone out of bed to drive 
# across town to restart a very remote firewall).
#
# For those administrators, we offer ADMINISABSENTMINDED=Yes. With this setting,
# when the firewall enters the 'stopped' state:
#
# All traffic that is part of or related to established connections is still
# allowed and all OUTPUT traffic is allowed. This is in addition to traffic
# to and from hosts listed in /etc/shorewall/routestopped.
#
# If this variable is not set or it is set to the null value then
# ADMINISABSENTMINDED=No is assumed.
#
ADMINISABSENTMINDED=Yes

#
# BLACKLIST Behavior
#
# Shorewall offers two types of blacklisting:
#
#	- static blacklisting through the /etc/shorewall/blacklist file together
#	  with the 'blacklist' interface option.
#	- dynamic blacklisting using the 'drop', 'reject' and 'allow' commands.
#
# The following variable determines whether the blacklist is checked for each
# packet or for each new connection.
#
#	BLACKLISTNEWONLY=Yes	Only consult blacklists for new connection
#				requests
#
#	BLACKLISTNEWONLY=No	Consult blacklists for all packets.
#
# If the BLACKLISTNEWONLY option is not set or is set to the empty value then
# BLACKLISTNEWONLY=No is assumed.
#
BLACKLISTNEWONLY=Yes

#
# Users with a large blacklist find that "shorwall [re]start" takes a long
# time and that new connections are disabled during that time. By setting
# DELAYBLACKLISTLOAD=Yes, you can cause Shorewall to enable new connections
# before loading the blacklist.

DELAYBLACKLISTLOAD=No

# MODULE NAME SUFFIX
#
# When loading a module named in /etc/shorewall/modules, Shorewall normally
# looks in the MODULES DIRECTORY (see MODULESDIR above) for files whose names
# end in ".o", ".ko", ".gz", "o.gz" or "ko.gz" . If your distribution uses a
# different naming convention then you can specify the suffix (extension) for
# module names in this variable.
#
# To see what suffix is used by your distribution:
#
#     ls /lib/modules/$(uname -r)/kernel/net/ipv4/netfilter
#
# All of the file names listed should have the same suffix (extension). Set
# MODULE_SUFFIX to that suffix.
#
# Examples: 
#
#	If all file names end with ".kzo" then set MODULE_SUFFIX="kzo"
#	If all file names end with ".kz.o" then set MODULE_SUFFIX="kz.o"
#

MODULE_SUFFIX=

#
# DISABLE IPV6
#
# Distributions (notably SuSE) are beginning to ship with IPV6
# enabled. If you are not using IPV6, you are at risk of being
# exploited by users who do. Setting DISABLE_IPV6=Yes will cause
# Shorewall to disable IPV6 traffic to/from and through your 
# firewall system. This requires that you have ip6tables installed.

DISABLE_IPV6=Yes

#
# BRIDGING
#
# If you wish to control traffic through a bridge (see http://bridge.sf.net),
# then set BRIDGING=Yes. Your kernel must have the physdev match option 
# enabled; that option is available at the above URL for 2.4 kernels and
# is included as a standard part of the 2.6 series kernels. If not
# specified or specified as empty (BRIDGING="") then "No" is assumed.
#

BRIDGING=No

#
# DYNAMIC ZONES
#
# If you need to be able to add and delete hosts from zones dynamically then
# set DYNAMIC_ZONES=Yes. Otherwise, set DYNAMIC_ZONES=No.

DYNAMIC_ZONES=No

#
# USE PKTTYPE MATCH 
#
# Some users have reported problems with the PKTTYPE match extension not being
# able to match certain broadcast packets. If you set PKTTYPE=No then Shorewall
# will use IP addresses to detect broadcasts rather than pkttype. If not given 
# or if given as empty (PKTTYPE="") then PKTTYPE=Yes is assumed.

PKTTYPE=Yes

#
# DROP INVALID PACKETS
#
# Netfilter classifies packets relative to its connection tracking table into
# four states:
#
#	NEW - thes packet initiates a new connection
#	ESTABLISHED - thes packet is part of an established connection
#	RELATED - thes packet is related to an established connection; it may
#	          establish a new connection
#	INVALID - the packet does not related to the table in any sensible way.
#
# Recent 2.6 kernels include code that evaluates TCP packets based on TCP 
# Window analysis. This can cause packets that were previously classified as 
# NEW or ESTABLISHED to be classified as INVALID.
#
# The new kernel code can be disabled by including this command in your
# /etc/shorewall/init file:
#
# echo 1 > /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_be_liberal
#
# Additional kernel logging about INVALID TCP packets may be obtained by
# adding this command to /etc/shorewall/init:
#
#  echo 1 > /proc/sys/net/ipv4/netfilter/ip_conntrack_log_invalid
#
# Traditionally, Shorewall has dropped INVALID TCP packets early. The DROPINVALID
# option allows INVALID packets to be passed through the normal rules chains by
# setting DROPINVALID=No.
#
# If not specified or if specified as empty (e.g., DROPINVALID="") then
# DROPINVALID=Yes is assumed.

DROPINVALID=No
################################################################################
#                       P A C K E T   D I S P O S I T I O N
################################################################################
#
# BLACKLIST DISPOSITION
#
# Set this variable to the action that you want to perform on packets from
# Blacklisted systems. Must be DROP or REJECT. If not set or set to empty,
# DROP is assumed.
#

BLACKLIST_DISPOSITION=DROP

#
# MAC List Disposition
#
# This variable determines the disposition of connection requests arriving
# on interfaces that have the 'maclist' option and that are from a device
# that is not listed for that interface in /etc/shorewall/maclist. Valid
# values are ACCEPT, DROP and REJECT. If not specified or specified as
# empty (MACLIST_DISPOSITION="") then REJECT is assumed

MACLIST_DISPOSITION=REJECT

#
# TCP FLAGS Disposition
#
# This variable determins the disposition of packets having an invalid
# combination of TCP flags that are received on interfaces having the
# 'tcpflags' option specified in /etc/shorewall/interfaces or in
# /etc/shorewall/hosts. If not specified or specified as empty
# (TCP_FLAGS_DISPOSITION="") then DROP is assumed.

TCP_FLAGS_DISPOSITION=DROP

#LAST LINE -- DO NOT REMOVE