Add an (optional) basic firewall configuration to setup2hd

The firewall will be configured and installed only when you use setup2hd
to install the Live OS to your hard drive.
The scripts are not particular to Slackware Live; you can easily copy
the resulting files /usr/sbin/myfwconfig, /etc/rc.d/rc.firewall
and /var/lib/pkgtools/setup/setup.firewall out of the installed system
and use them anywhere on a Slackware-compatible OS.

- The 'myfwconfig' script will ask a few simple questions and generate the
ipv4 and ipv6 configuration in /etc/firewall/.
- The 'rc.firewall' script will load/save its iptables/ip6tables
  configuration from /etc/firewall/ files.
- The 'setup.firewall' script is a convenient way to call the firewall
  configurator from pkgtools or during Slackware's installation to harddisk.

1 files changed, 704 insertions, 0 deletions

diff --git a/setup2hd/SeTfirewall.tpl b/setup2hd/SeTfirewall.tpl
new file mode 100644
index 0000000..144794f
--- /dev/null
+++ b/setup2hd/SeTfirewall.tpl
@@ -0,0 +1,704 @@
+#!/bin/bash
+
+# ------------------------------------------------------------------------------
+# Configure a basic firewall,
+# by generating a set of iptables rules (ipv4 and ipv6),
+# and saving those to /etc/firewall/ipv4 and /etc/firewall/ipv6 .
+# The accompanying script /etc/rc.d/rc.firewall will restore these configs.
+#
+# This script and rc.firewall are part of liveslak,
+# a project by Eric Hameleers, see https://download.liveslak.org/
+#
+# Iptables ruleset handling courtesy of Easy Firewall Generator for IPTables,
+# Copyright 2002 Timothy Scott Morizot
+# ------------------------------------------------------------------------------
+
+# The script accepts one parameter: the target filesystem:
+DESTDIR="$1"
+
+# This tmp directory is only writable by root:
+TMP=${TMP:-"/var/log/setup/tmp"}
+if [ ! -d $TMP ]; then
+  mkdir -p $TMP
+fi
+
+# The script defaults to curses dialog but Xdialog is a good alternative:
+DIALOG=${DIALOG:-"dialog"}
+
+# The iptables tools we use:
+IPT="/usr/sbin/iptables"
+IP6T="/usr/sbin/ip6tables"
+IPTS="/usr/sbin/iptables-save"
+IP6TS="/usr/sbin/ip6tables-save"
+IPTR="/usr/sbin/iptables-restore"
+IP6TR="/usr/sbin/ip6tables-restore"
+
+# Localhost Interface
+LO_IFACE="lo"
+LO_IP="127.0.0.1"
+LO_IP6="::1"
+
+# The default gateway device will be our primary candidate to firewall:
+GWDEV=$(/sbin/ip route show |grep ^default |cut -d' ' -f5)
+
+# Generate a list of network devices, minus the default gateway and loopback:
+AVAILDEV=$(ls --indicator-style=none /sys/class/net/ |sed -e "s/${GWDEV}//" -e "s/lo//")
+
+# Store all network interfaces in an associative array:
+declare -A NETDEVARR
+NETDEVARR=( [$GWDEV]=on )
+for INDEV in $AVAILDEV ; do NETDEVARR+=( [$INDEV]=off ) ; done
+unset INDEV
+
+# Store network services in another array:
+declare -A SERVARR=( 
+  ['SSH']=off
+  ['RSYNC']=off
+  ['GIT']=off
+  ['HTTP']=off
+  ['HTTPS']=off
+  ['SMTP']=off
+  ['SMPTS']=off
+  ['IMAP']=off
+  ['IMAPS']=off
+  ['NTP']=off
+)
+
+# Store the list of custom ports/port ranges:
+CUSTOM_TCP_LIST=""
+CUSTOM_UDP_LIST=""
+
+# Will we auto-configure a restrictive firewall?
+AUTOCONFIG="YES"
+
+# User pressing ESC will change the default choice in the 1st dialog:
+DEFAULTNO=""
+
+# Loop over the configuration until the user is done:
+MAINSELECT="start"
+while [ "$MAINSELECT" != "done" ]; do
+  if [ "$MAINSELECT" = "start" ]; then
+    ${DIALOG} --backtitle "@UDISTRO@ (@LIVEDE@) Basic Firewall Setup" \
+      --title "CONFIGURE FIREWALL" ${DEFAULTNO} \
+      --yesno "Would you like to protect the system with a basic firewall?\n\n\
+You can either block all external connections,
+or you can expose specific TCP/UDP ports.\n\n\
+DHCP will never be blocked." 11 68
+    if [ $? != 0 ]; then
+      # Not needed.
+      exit 0
+    else
+      DEFAULTNO=""
+    fi
+    MAINSELECT="devices"
+  fi
+
+  if [ "$MAINSELECT" = "devices" ]; then
+    # Populate the network device checklist for the dialog:
+    NETDEVLIST="$(for I in ${!NETDEVARR[@]};do echo $I ${NETDEVARR[$I]};done)"
+    unset I
+    ${DIALOG} --backtitle "@UDISTRO@ (@LIVEDE@) Basic Firewall Setup" \
+      --title "PICK INTERFACES" \
+      --stdout --separate-output \
+      --no-items \
+      --ok-label "Next" --no-cancel --extra-button --extra-label "Previous" \
+      --checklist "\
+Select the network interface(s) exposed to the outside world.\n\
+Your default gateway is pre-selected.\n\
+Un-selected interfaces will accept all incoming traffic." 13 68 5 $NETDEVLIST \
+    > $TMP/SeTnics
+    RETVAL=$?
+    # Zero out the array values and re-enable only the ones we got returned:
+    for INDEV in ${!NETDEVARR[@]} ; do NETDEVARR[$INDEV]=off ; done
+    for INDEV in $(cat $TMP/SeTnics) ; do  NETDEVARR[$INDEV]=on ; done
+    unset INDEV
+    case "$RETVAL" in
+      0) MAINSELECT="autoselect" ;;
+      3) MAINSELECT="start" ;;
+      *) MAINSELECT="start" ; DEFAULTNO="--defaultno" ;;
+    esac
+    rm -f $TMP/SeTnics
+  fi
+
+  if [ "$MAINSELECT" = "autoselect" ]; then
+    ${DIALOG} --backtitle "@UDISTRO@ (@LIVEDE@) Basic Firewall Setup" \
+      --title "ALL CLOSED?" \
+      --yesno "Do you want to block all incoming external connections?\n\
+If 'no', then you will be able to specify ports that need to be open." 7 68
+    RETVAL=$?
+    case "$RETVAL" in
+      0) AUTOCONFIG="YES"
+         MAINSELECT="done" ;;
+      1) AUTOCONFIG="NO"
+         MAINSELECT="services" ;;
+      *) MAINSELECT="start" ; DEFAULTNO="--defaultno" ;;
+    esac
+  fi
+
+  if [ "$MAINSELECT" = "services" ]; then
+    # Populate the services checklist for the dialog:
+    ${DIALOG} --backtitle "@UDISTRO@ (@LIVEDE@) Basic Firewall Setup" \
+      --title "OPEN PORTS" \
+      --stdout --separate-output \
+      --ok-label "Next" --no-cancel --extra-button --extra-label "Previous" \
+      --checklist "\
+Select the service ports you want to remain open for the outside world.\n\
+You can enter more ports or portranges in the next dialog." 19 68 13 \
+SSH    'SSH (port 22)'                             ${SERVARR['SSH']} \
+RSYNC  'RSYNC (port 873)'                          ${SERVARR['RSYNC']} \
+GIT    'GIT (port 9418)'                           ${SERVARR['GIT']} \
+HTTP   'Web Server (HTTP port 80)'                 ${SERVARR['HTTP']} \
+HTTPS  'Secure Web Server (HTTPS port 443)'        ${SERVARR['HTTPS']} \
+SMTP   'Receiving Email (SMTP port 25)'            ${SERVARR['SMTP']} \
+SMTPS  'Secure Receiving Email (SMPTS port 587)'   ${SERVARR['SMPTS']} \
+IMAP   'IMAP Email Server (IMAP port 143)'         ${SERVARR['IMAP']} \
+IMAPS  'Secure IMAP Email Server (IMAPS port 993)' ${SERVARR['IMAPS']} \
+NTP    'Time Server (NTP port 123)'                ${SERVARR['NTP']} \
+    > $TMP/SeTservices
+    RETVAL=$?
+    # Zero out the array values and re-enable only the ones we got returned:
+    for INSRV in ${!SERVARR[@]} ; do SERVARR[$INSRV]=off ; done
+    for INSRV in $(cat $TMP/SeTservices) ; do  SERVARR[$INSRV]=on ; done
+    unset INSRV
+    case $RETVAL in
+      0) MAINSELECT="customports" ;;
+      3) MAINSELECT="autoselect" ;;
+      *) MAINSELECT="start" ; DEFAULTNO="--defaultno" ;;
+    esac
+    rm -f $TMP/SeTservices
+  fi
+
+  if [ "$MAINSELECT" = "customports" ]; then
+    ${DIALOG} --backtitle "@UDISTRO@ (@LIVEDE@) Basic Firewall Setup" \
+      --title "CUSTOM PORTS" \
+      --stdout \
+      --ok-label "Next" --no-cancel --extra-button --extra-label "Previous" \
+      --form "\
+Enter additional ports or port ranges.\n\
+Port ranges consist of two numbers separated by a colon (example: 3000:3011).\n\
+Separate multiple entries with commas,\n\
+for example: 22,465,3000:3011,6660:6669,7000" \
+13 68 2 \
+"TCP ports/portranges:"  1 1 "$CUSTOM_TCP_LIST" 1 25 40 0 \
+"UDP ports/portranges:"  2 1 "$CUSTOM_UDP_LIST" 2 25 40 0 \
+    > $TMP/SeTcustomports
+    RETVAL=$?
+    CUSTOM_TCP_LIST=$(head -1 $TMP/SeTcustomports)
+    CUSTOM_UDP_LIST=$(tail -1 $TMP/SeTcustomports)
+    case $RETVAL in
+      0) MAINSELECT="confirm" ;;
+      3) MAINSELECT="services" ;;
+      *) MAINSELECT="start" ; DEFAULTNO="--defaultno" ;;
+    esac
+    rm -f $TMP/SeTcustomports
+  fi
+
+  if [ "$MAINSELECT" = "confirm" ]; then
+    # Collect all service ports that need to be remotely accessible.
+    # TCP:
+    TCP_LIST=""
+    if [ "${SERVARR['HTTP']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 80"
+    fi
+    if [ "${SERVARR['HTTPS']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 443"
+    fi
+    if [ "${SERVARR['SMTP']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 25"
+    fi
+    if [ "${SERVARR['SMTPS']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 587"
+    fi
+    if [ "${SERVARR['IMAP']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 143"
+    fi
+    if [ "${SERVARR['IMAPS']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 993"
+    fi
+    if [ "${SERVARR['SSH']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 22"
+    fi
+    if [ "${SERVARR['GIT']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 9418"
+    fi
+    if [ "${SERVARR['RSYNC']}" = "on" ]; then
+      TCP_LIST="$TCP_LIST 873"
+    fi
+    TCP_LIST=$(echo $TCP_LIST | sed 's/^ *//g' | tr ' ' ',')
+    # UDP:
+    UDP_LIST=""
+    if [ "${SERVARR['NTP']}" = "on" ]; then
+      UDP_LIST="$UDP_LIST 123"
+    fi
+    if [ "${SERVARR['RSYNC']}" = "on" ]; then
+      UDP_LIST="$UDP_LIST 873"
+    fi
+    UDP_LIST=$(echo $UDP_LIST | sed 's/^ *//g' | tr ' ' ',')
+
+    TCP_LIST=$(echo $TCP_LIST $CUSTOM_TCP_LIST | sed 's/^ *//g' | tr ' ' ',')
+    UDP_LIST=$(echo $UDP_LIST $CUSTOM_UDP_LIST | sed 's/^ *//g' | tr ' ' ',')
+    DEV_LIST=$(for INDEV in ${!NETDEVARR[@]} ; do if [ "${NETDEVARR[$INDEV]}" = "on" ]; then echo -n $INDEV ; fi ; done)
+
+    ${DIALOG} --backtitle "@UDISTRO@ (@LIVEDE@) Basic Firewall Setup" \
+      --title "CONFIRM CONFIGURATION" \
+      --yes-label "Generate" --no-label "Redo" \
+      --yesno "These are the ports you configured. Are you OK with them?\n\n\
+Press 'Generate' to generate the firewall configuration.\n\
+Else press 'Redo' to re-do the setup.\n\n\
+Firewalled interface(s): $DEV_LIST \n\
+TCP Ports: $TCP_LIST \n\
+UDP Ports: $UDP_LIST" 12 68
+    RETVAL=$?
+    case $RETVAL in
+      0) MAINSELECT="done" ;;
+      1) MAINSELECT="devices" ;;
+      *) MAINSELECT="start" ; DEFAULTNO="--defaultno" ;;
+    esac
+  fi
+
+done
+
+# ------------------------------------------------------------------------------
+# End of configuration, let's get to work.
+# ------------------------------------------------------------------------------
+
+#
+# Flush Any Existing Rules or Chains
+#
+
+${DIALOG} --backtitle "@UDISTRO@ (@LIVEDE@) Basic Firewall Setup" \
+  --infobox "Configuring your firewall ..." 4 68
+
+# Reset Default Policies
+$IPT -P INPUT ACCEPT
+$IPT -P FORWARD ACCEPT
+$IPT -P OUTPUT ACCEPT
+$IPT -t nat -P PREROUTING ACCEPT
+$IPT -t nat -P POSTROUTING ACCEPT
+$IPT -t nat -P OUTPUT ACCEPT
+$IPT -t mangle -P PREROUTING ACCEPT
+$IPT -t mangle -P OUTPUT ACCEPT
+#
+$IP6T -P INPUT ACCEPT
+$IP6T -P FORWARD ACCEPT
+$IP6T -P OUTPUT ACCEPT
+$IP6T -t mangle -P PREROUTING ACCEPT
+$IP6T -t mangle -P OUTPUT ACCEPT
+
+# Flush all rules
+$IPT -F
+$IPT -t nat -F
+$IPT -t mangle -F
+#
+$IP6T -F
+$IP6T -t mangle -F
+
+# Erase all non-default chains
+$IPT -X
+$IPT -t nat -X
+$IPT -t mangle -X
+#
+$IP6T -X
+$IP6T -t mangle -X
+
+#
+# Rules Configuration
+#
+# Filter Table
+#
+
+# Set Policies
+$IPT -P INPUT DROP
+$IPT -P OUTPUT DROP
+$IPT -P FORWARD DROP
+#
+$IP6T -P INPUT DROP
+$IP6T -P OUTPUT DROP
+$IP6T -P FORWARD DROP
+
+#
+# User-Specified Chains
+#
+# Create user chains to reduce the number of rules each packet must traverse.
+#
+
+# Create a chain to filter INVALID packets
+$IPT -N bad_packets
+$IP6T -N bad_packets
+
+# Create another chain to filter bad tcp packets
+$IPT -N bad_tcp_packets
+$IP6T -N bad_tcp_packets
+
+# Create separate chains for icmp, tcp (incoming and outgoing),
+# and incoming udp packets.
+$IPT -N icmp_packets
+$IP6T -N icmp_packets
+
+# Used for UDP packets inbound from the Internet
+$IPT -N udp_inbound
+$IP6T -N udp_inbound
+
+# Used to block outbound UDP services from internal network
+# Default to allow all
+$IPT -N udp_outbound
+$IP6T -N udp_outbound
+
+# Used to allow inbound services if desired
+# Default fail except for established sessions
+$IPT -N tcp_inbound
+$IP6T -N tcp_inbound
+
+# Used to block outbound services from internal network
+# Default to allow all
+$IPT -N tcp_outbound
+$IP6T -N tcp_outbound
+
+#
+# Populate User Chains
+#
+# bad_packets chain
+#
+
+# Drop INVALID packets immediately
+$IPT -A bad_packets -p ALL -m state --state INVALID -j DROP
+$IP6T -A bad_packets -p ALL -m state --state INVALID -j DROP
+
+# Then check the tcp packets for additional problems
+$IPT -A bad_packets -p tcp -j bad_tcp_packets
+$IP6T -A bad_packets -p tcp -j bad_tcp_packets
+
+# All good, so return
+$IPT -A bad_packets -p ALL -j RETURN
+$IP6T -A bad_packets -p ALL -j RETURN
+
+# bad_tcp_packets chain
+#
+# All tcp packets will traverse this chain.
+# Every new connection attempt should begin with
+# a syn packet.  If it doesn't, it is likely a
+# port scan.  This drops packets in state
+# NEW that are not flagged as syn packets.
+$IPT -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j DROP
+$IP6T -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j DROP
+$IPT -A bad_tcp_packets -p tcp --tcp-flags ALL NONE -j DROP
+$IP6T -A bad_tcp_packets -p tcp --tcp-flags ALL NONE -j DROP
+$IPT -A bad_tcp_packets -p tcp --tcp-flags ALL ALL -j DROP
+$IP6T -A bad_tcp_packets -p tcp --tcp-flags ALL ALL -j DROP
+$IPT -A bad_tcp_packets -p tcp --tcp-flags ALL FIN,URG,PSH -j DROP
+$IP6T -A bad_tcp_packets -p tcp --tcp-flags ALL FIN,URG,PSH -j DROP
+$IPT -A bad_tcp_packets -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP
+$IP6T -A bad_tcp_packets -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP
+$IPT -A bad_tcp_packets -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
+$IP6T -A bad_tcp_packets -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
+$IPT -A bad_tcp_packets -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
+$IP6T -A bad_tcp_packets -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
+
+# All good, so return
+$IPT -A bad_tcp_packets -p tcp -j RETURN
+$IP6T -A bad_tcp_packets -p tcp -j RETURN
+
+# icmp_packets chain
+#
+# This chain is for inbound (from the Internet) icmp packets only.
+# Type 8 (Echo Request) is not accepted by default
+# Enable it if you want remote hosts to be able to reach you.
+# 11 (Time Exceeded) is the only one accepted
+# that would not already be covered by the established
+# connection rule.  Applied to INPUT on the external interface.
+# 
+# See: http://www.ee.siue.edu/~rwalden/networking/icmp.html
+# for more info on ICMP types.
+#
+# Note that the stateful settings allow replies to ICMP packets.
+# These rules allow new packets of the specified types.
+
+# ICMP packets should fit in a Layer 2 frame, thus they should
+# never be fragmented.  Fragmented ICMP packets are a typical sign
+# of a denial of service attack.
+$IPT -A icmp_packets --fragment -p icmp -j DROP
+$IP6T -A icmp_packets -p ipv6-icmp -m ipv6header --header frag --soft -j DROP
+
+# Echo - uncomment to allow your system to be pinged.
+# $IPT -A icmp_packets -p icmp -s 0/0 --icmp-type 8 -j ACCEPT
+# $IP6T -A icmp_packets -p ipv6-icmp -s 0/0 --icmpv6-type 8 -j ACCEPT
+
+# By default, however, drop pings without logging. Blaster
+# and other worms have infected systems blasting pings.
+# Comment the line below if you want pings logged, but it
+# will likely fill your logs.
+$IPT -A icmp_packets -p icmp -s 0/0 --icmp-type 8 -j DROP
+$IP6T -A icmp_packets -p ipv6-icmp -s 0/0 --icmpv6-type 8 -j DROP
+
+# Time Exceeded
+$IPT -A icmp_packets -p icmp -s 0/0 --icmp-type 11 -j ACCEPT
+$IP6T -A icmp_packets -p ipv6-icmp -s 0/0 --icmpv6-type 11 -j ACCEPT
+
+# Not matched, so return so it will be logged
+$IPT -A icmp_packets -p icmp -j RETURN
+$IP6T -A icmp_packets -p ipv6-icmp -j RETURN
+
+# TCP & UDP
+# Identify ports at:
+#    http://www.chebucto.ns.ca/~rakerman/port-table.html
+#    http://www.iana.org/assignments/port-numbers
+
+# udp_inbound chain
+#
+# This chain describes the inbound UDP packets it will accept.
+# It's applied to INPUT on the external or Internet interface.
+# Note that the stateful settings allow replies.
+# These rules are for new requests.
+# It drops netbios packets (windows) immediately without logging.
+
+# Drop netbios calls
+# Please note that these rules do not really change the way the firewall
+# treats netbios connections.  Connections from the localhost and
+# internal interface (if one exists) are accepted by default.
+# Responses from the Internet to requests initiated by or through
+# the firewall are also accepted by default.  To get here, the
+# packets would have to be part of a new request received by the
+# Internet interface.  You would have to manually add rules to
+# accept these.  I added these rules because some network connections,
+# such as those via cable modems, tend to be filled with noise from
+# unprotected Windows machines.  These rules drop those packets
+# quickly and without logging them.  This prevents them from traversing
+# the whole chain and keeps the log from getting cluttered with
+# chatter from Windows systems.
+$IPT -A udp_inbound -p udp -s 0/0 --dport 137 -j DROP
+$IPT -A udp_inbound -p udp -s 0/0 --dport 138 -j DROP
+$IP6T -A udp_inbound -p udp -s 0/0 --dport 137 -j DROP
+$IP6T -A udp_inbound -p udp -s 0/0 --dport 138 -j DROP
+
+# Ident requests (Port 113) must have a REJECT rule rather than the
+# default DROP rule.  This is the minimum requirement to avoid
+# long delays while connecting.  Also see the tcp_inbound rule.
+$IPT -A udp_inbound -p udp -s 0/0 --dport 113 -j REJECT
+$IP6T -A udp_inbound -p udp -s 0/0 --dport 113 -j REJECT
+
+# A more sophisticated configuration could accept the ident requests.
+# $IPT -A udp_inbound -p udp -s 0/0 --dport 113 -j ACCEPT
+# $IP6T -A udp_inbound -p udp -s 0/0 --dport 113 -j ACCEPT
+
+# IPv4 only:
+# Allow DHCP client request packets inbound from external network
+$IPT -A udp_inbound -p udp -s 0/0 --source-port 68 --dport 67 \
+   -j ACCEPT
+# Dynamic Address
+# If DHCP, the initial request is a broadcast. The response
+# doesn't exactly match the outbound packet.  This explicitly
+# allow the DHCP ports to alleviate this problem.
+# If you receive your dynamic address by a different means, you
+# can probably comment this line.
+$IPT -A udp_inbound -p udp -s 0/0 --source-port 67 --dport 68 \
+   -j ACCEPT
+
+# Open the custom UDP ports if they have been configured:
+if [ -n "$UDP_LIST" ]; then 
+  $IPT -A INPUT -p udp -m multiport --dport $UDP_LIST -j ACCEPT
+  $IP6T -A INPUT -p udp -m multiport --dport $UDP_LIST -j ACCEPT
+fi
+
+# Not matched, so return for logging
+$IPT -A udp_inbound -p udp -j RETURN
+$IP6T -A udp_inbound -p udp -j RETURN
+
+# udp_outbound chain
+#
+# This chain is used with a private network to prevent forwarding for
+# UDP requests on specific protocols.  Applied to the FORWARD rule from
+# the internal network.  Ends with an ACCEPT
+
+
+# No match, so ACCEPT
+$IPT -A udp_outbound -p udp -s 0/0 -j ACCEPT
+$IP6T -A udp_outbound -p udp -s 0/0 -j ACCEPT
+
+# tcp_inbound chain
+#
+# This chain is used to allow inbound connections to the
+# system/gateway.  Use with care.  It defaults to none.
+# It's applied on INPUT from the external or Internet interface.
+
+# Ident requests (Port 113) must have a REJECT rule rather than the
+# default DROP rule.  This is the minimum requirement to avoid
+# long delays while connecting.  Also see the tcp_inbound rule.
+$IPT -A tcp_inbound -p tcp -s 0/0 --dport 113 -j REJECT
+$IP6T -A tcp_inbound -p tcp -s 0/0 --dport 113 -j REJECT
+
+# A more sophisticated configuration could accept the ident requests.
+# $IPT -A tcp_inbound -p tcp -s 0/0 --dport 113 -j ACCEPT
+# $IP6T -A tcp_inbound -p tcp -s 0/0 --dport 113 -j ACCEPT
+
+# Open the requested TCP service ports if they have been configured:
+if [ -n "$TCP_LIST" ]; then 
+  $IPT -A INPUT -p tcp -m multiport --dport $TCP_LIST -j ACCEPT
+  $IP6T -A INPUT -p tcp -m multiport --dport $TCP_LIST -j ACCEPT
+fi
+
+# Not matched, so return so it will be logged
+$IPT -A tcp_inbound -p tcp -j RETURN
+$IP6T -A tcp_inbound -p tcp -j RETURN
+
+# tcp_outbound chain
+#
+# This chain is used with a private network to prevent forwarding for
+# requests on specific protocols.  Applied to the FORWARD rule from
+# the internal network.  Ends with an ACCEPT
+
+# No match, so ACCEPT
+$IPT -A tcp_outbound -p tcp -s 0/0 -j ACCEPT
+$IP6T -A tcp_outbound -p tcp -s 0/0 -j ACCEPT
+
+#
+# INPUT Chain
+#
+# Allow all on localhost interface
+$IPT -A INPUT -p ALL -i $LO_IFACE -j ACCEPT
+$IP6T -A INPUT -p ALL -i $LO_IFACE -j ACCEPT
+
+# Allow all on other internal interfaces:
+for INDEV in ${!NETDEVARR[@]} ; do
+  if [ "${NETDEVARR[$INDEV]}" = "off" ] ; then
+    $IPT -A INPUT -p ALL -i $INDEV -j ACCEPT
+    $IP6T -A INPUT -p ALL -i $INDEV -j ACCEPT
+  fi
+done
+unset INDEV
+
+# Drop bad packets
+$IPT -A INPUT -p ALL -j bad_packets
+$IP6T -A INPUT -p ALL -j bad_packets
+
+# DOCSIS compliant cable modems
+# Some DOCSIS compliant cable modems send IGMP multicasts to find
+# connected PCs.  The multicast packets have the destination address
+# 224.0.0.1.  You can accept them.  If you choose to do so,
+# Uncomment the rule to ACCEPT them and comment the rule to DROP
+# them  The firewall will drop them here by default to avoid
+# cluttering the log.  The firewall will drop all multicasts
+# to the entire subnet (224.0.0.1) by default.  To only affect
+# IGMP multicasts, change '-p ALL' to '-p 2'.  Of course,
+# if they aren't accepted elsewhere, it will only ensure that
+# multicasts on other protocols are logged.
+# Drop them without logging.
+$IPT -A INPUT -p ALL -d 224.0.0.1 -j DROP
+# The rule to accept the packets.
+# $IPT -A INPUT -p ALL -d 224.0.0.1 -j ACCEPT
+
+# Inbound Internet Packet Rules
+
+for INDEV in ${!NETDEVARR[@]} ; do
+  if [ "${NETDEVARR[$INDEV]}" = "on" ] ; then
+    # Accept Established Connections
+    $IPT -A INPUT -p ALL -i $INDEV -m state --state ESTABLISHED,RELATED \
+         -j ACCEPT
+    $IP6T -A INPUT -p ALL -i $INDEV -m state --state ESTABLISHED,RELATED \
+         -j ACCEPT
+
+    # Route the rest to the appropriate user chain
+    $IPT -A INPUT -p tcp -i $INDEV -j tcp_inbound
+    $IP6T -A INPUT -p tcp -i $INDEV -j tcp_inbound
+    $IPT -A INPUT -p udp -i $INDEV -j udp_inbound
+    $IP6T -A INPUT -p udp -i $INDEV -j udp_inbound
+    $IPT -A INPUT -p icmp -i $INDEV -j icmp_packets
+    $IP6T -A INPUT -p ipv6-icmp -i $INDEV -j icmp_packets
+  fi
+done
+unset INDEV
+
+# Drop without logging broadcasts that get this far.
+# Cuts down on log clutter.
+# Comment this line if testing new rules that impact
+# broadcast protocols.
+$IPT -A INPUT -m pkttype --pkt-type broadcast -j DROP
+$IP6T -A INPUT -m pkttype --pkt-type broadcast -j DROP
+
+# Log packets that still don't match
+$IPT -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \
+    --log-prefix "INPUT packet died: "
+$IP6T -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \
+    --log-prefix "INPUT packet ipv6 died: "
+
+#
+# FORWARD Chain
+#
+# Used if forwarding for a private network
+
+#
+# OUTPUT Chain
+#
+# Generally trust the firewall on output
+
+# However, invalid icmp packets need to be dropped
+# to prevent a possible exploit.
+$IPT -A OUTPUT -m state -p icmp --state INVALID -j DROP
+$IP6T -A OUTPUT -m state -p ipv6-icmp --state INVALID -j DROP
+
+# Localhost
+$IPT -A OUTPUT -p ALL -s $LO_IP -j ACCEPT
+$IP6T -A OUTPUT -p ALL -s $LO_IP6 -j ACCEPT
+$IPT -A OUTPUT -p ALL -o $LO_IFACE -j ACCEPT
+$IP6T -A OUTPUT -p ALL -o $LO_IFACE -j ACCEPT
+
+# Allow all on other internal interfaces:
+for OUTDEV in ${!NETDEVARR[@]} ; do
+  if [ "${NETDEVARR[$OUTDEV]}" = "off" ] ; then
+    $IPT -A OUTPUT -p ALL -o $OUTDEV -j ACCEPT
+    $IP6T -A OUTPUT -p ALL -o $OUTDEV -j ACCEPT
+  fi
+done
+unset OUTDEV
+
+# To internet
+for OUTDEV in ${!NETDEVARR[@]} ; do
+  if [ "${NETDEVARR[$OUTDEV]}" = "on" ] ; then
+    $IPT -A OUTPUT -p ALL -o $OUTDEV -j ACCEPT
+    $IP6T -A OUTPUT -p ALL -o $OUTDEV -j ACCEPT
+  fi
+done
+
+# Log packets that still don't match
+$IPT -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \
+    --log-prefix "OUTPUT packet died: "
+$IP6T -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \
+    --log-prefix "OUTPUT packet ipv6 died: "
+
+#
+# nat table
+#
+# The nat table is where network address translation occurs if there
+# is a private network.  If the gateway is connected to the Internet
+# with a static IP, snat is used.  If the gateway has a dynamic address,
+# masquerade must be used instead.  There is more overhead associated
+# with masquerade, so snat is better when it can be used.
+# The nat table has a builtin chain, PREROUTING, for dnat and redirects.
+# Another, POSTROUTING, handles snat and masquerade.
+
+#
+# PREROUTING chain
+#
+
+#
+# POSTROUTING chain
+#
+
+
+#
+# mangle table
+#
+# The mangle table is used to alter packets.  It can alter or mangle them in
+# several ways.  For the purposes of this generator, we only use its ability
+# to alter the TTL in packets.  However, it can be used to set netfilter
+# mark values on specific packets.  Those marks could then be used in another
+# table like filter, to limit activities associated with a specific host, for
+# instance.  The TOS target can be used to set the Type of Service field in
+# the IP header.  Note that the TTL target might not be included in the
+# distribution on your system.  If it is not and you require it, you will
+# have to add it.  That may require that you build from source.
+
+# Save the firewall configuration so that 'rc.firewall' can load it:
+mkdir -p $DESTDIR/etc/firewall
+${IPTS} > $DESTDIR/etc/firewall/ipv4
+${IP6TS} > $DESTDIR/etc/firewall/ipv6
+