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 #!/bin/sh
 #
 # Generated iptables firewall script for the Linux 2.4 kernel and later.
 # Script generated by Easy Firewall Generator for IPTables 1.15
 # copyright 2002 Timothy Scott Morizot
 # Modified for Slackware Linux by Eric Hameleers <[email protected]>
 #
 # This generator is adapted from the original to work on Slackware Linux.
 # Basically, I corrected the path name to the iptables* commands
 # and re-wrote this comment.
 #
 # It can be executed with the typical start and stop arguments.
 # If used with stop, it will stop after flushing the firewall.
 # The save and restore arguments will save or restore the rules
 # from the /etc/sysconfig/iptables file.  The save and restore
 # arguments are included to preserve compatibility with
 # Redhat's or Fedora's init.d script if you prefer to use it.
 
 # You may want to save this script as /etc/rc.d/rc.firewall
 # and make it executable, like this:
 #   chmod +x /etc/rc.d/rc.firewall
 # Slackware Linux will then automatically run this script
 # with the "start" parameter.
 
 ###############################################################################
 #
 # Local Settings
 #
 
 # sysctl location.  If set, it will use sysctl to adjust the kernel parameters.
 # If this is set to the empty string (or is unset), the use of sysctl
 # is disabled.
 
 SYSCTL="/sbin/sysctl -w"
 
 # To echo the value directly to the /proc file instead
 # SYSCTL=""
 
 # IPTables Location - adjust if needed
 
 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"
 
 # Internet Interface
 INET_IFACE="+"
 
 # Localhost Interface
 
 LO_IFACE="lo"
 LO_IP="127.0.0.1"
 LO_IP6="::1"
 
 # Save and Restore arguments handled here
 if [ "$1" = "save" ]
 then
 	echo -n "Saving firewall to /etc/sysconfig/iptables ... "
 	$IPTS > /etc/sysconfig/iptables
 	$IP6TS > /etc/sysconfig/ip6tables
 	echo "done"
 	exit 0
 elif [ "$1" = "restore" ]
 then
 	echo -n "Restoring firewall from /etc/sysconfig/iptables ... "
 	$IPTR < /etc/sysconfig/iptables
 	$IP6TR < /etc/sysconfig/ip6tables
 	echo "done"
 	exit 0
 fi
 
 ###############################################################################
 #
 # Load Modules
 #
 
 echo "Loading kernel modules ..."
 
 # You should uncomment the line below and run it the first time just to
 # ensure all kernel module dependencies are OK.  There is no need to run
 # every time, however.
 
 # /sbin/depmod -a
 
 # Unless you have kernel module auto-loading disabled, you should not
 # need to manually load each of these modules.  Other than ip_tables,
 # ip_conntrack, and some of the optional modules, I've left these
 # commented by default.  Uncomment if you have any problems or if
 # you have disabled module autoload.  Note that some modules must
 # be loaded by another kernel module.
 
 # core netfilter module
 # /sbin/modprobe ip_tables
 
 # the stateful connection tracking module
 # /sbin/modprobe ip_conntrack
 
 # filter table module
 # /sbin/modprobe iptable_filter
 
 # mangle table module
 # /sbin/modprobe iptable_mangle
 
 # nat table module
 # /sbin/modprobe iptable_nat
 
 # LOG target module
 # /sbin/modprobe ipt_LOG
 
 # This is used to limit the number of packets per sec/min/hr
 # /sbin/modprobe ipt_limit
 
 # masquerade target module
 # /sbin/modprobe ipt_MASQUERADE
 
 # filter using owner as part of the match
 # /sbin/modprobe ipt_owner
 
 # REJECT target drops the packet and returns an ICMP response.
 # The response is configurable.  By default, connection refused.
 # /sbin/modprobe ipt_REJECT
 
 # This target allows packets to be marked in the mangle table
 # /sbin/modprobe ipt_mark
 
 # This target affects the TCP MSS
 # /sbin/modprobe ipt_tcpmss
 
 # This match allows multiple ports instead of a single port or range
 # /sbin/modprobe multiport
 
 # This match checks against the TCP flags
 # /sbin/modprobe ipt_state
 
 # This match catches packets with invalid flags
 # /sbin/modprobe ipt_unclean
 
 # The ftp nat module is required for non-PASV ftp support
 /sbin/modprobe ip_nat_ftp
 
 # the module for full ftp connection tracking
 /sbin/modprobe ip_conntrack_ftp
 
 # the module for full irc connection tracking
 /sbin/modprobe ip_conntrack_irc
 
 
 ###############################################################################
 #
 # Kernel Parameter Configuration
 #
 # See http://ipsysctl-tutorial.frozentux.net/chunkyhtml/index.html
 # for a detailed tutorial on sysctl and the various settings
 # available.
 
 # Required to enable IPv4 forwarding.
 # Redhat users can try setting FORWARD_IPV4 in /etc/sysconfig/network to true
 # Alternatively, it can be set in /etc/sysctl.conf
 #if [ "$SYSCTL" = "" ]
 #then
 #    echo "1" > /proc/sys/net/ipv4/ip_forward
 #else
 #    $SYSCTL net.ipv4.ip_forward="1"
 #fi
 
 # This enables dynamic address hacking.
 # This may help if you have a dynamic IP address \(e.g. slip, ppp, dhcp\).
 #if [ "$SYSCTL" = "" ]
 #then
 #    echo "1" > /proc/sys/net/ipv4/ip_dynaddr
 #else
 #    $SYSCTL net.ipv4.ip_dynaddr="1"
 #fi
 
 # This enables SYN flood protection.
 # The SYN cookies activation allows your system to accept an unlimited
 # number of TCP connections while still trying to give reasonable
 # service during a denial of service attack.
 if [ "$SYSCTL" = "" ]
 then
     echo "1" > /proc/sys/net/ipv4/tcp_syncookies
 else
     $SYSCTL net.ipv4.tcp_syncookies="1"
 fi
 
 # This enables source validation by reversed path according to RFC1812.
 # In other words, did the response packet originate from the same interface
 # through which the source packet was sent?  It's recommended for single-homed
 # systems and routers on stub networks.  Since those are the configurations
 # this firewall is designed to support, I turn it on by default.
 # Turn it off if you use multiple NICs connected to the same network.
 if [ "$SYSCTL" = "" ]
 then
     echo "1" > /proc/sys/net/ipv4/conf/all/rp_filter
 else
     $SYSCTL net.ipv4.conf.all.rp_filter="1"
 fi
 
 # This option allows a subnet to be firewalled with a single IP address.
 # It's used to build a DMZ.  Since that's not a focus of this firewall
 # script, it's not enabled by default, but is included for reference.
 # See: http://www.sjdjweis.com/linux/proxyarp/
 #if [ "$SYSCTL" = "" ]
 #then
 #    echo "1" > /proc/sys/net/ipv4/conf/all/proxy_arp
 #else
 #    $SYSCTL net.ipv4.conf.all.proxy_arp="1"
 #fi
 
 # The following kernel settings were suggested by Alex Weeks. Thanks!
 
 # This kernel parameter instructs the kernel to ignore all ICMP
 # echo requests sent to the broadcast address.  This prevents
 # a number of smurfs and similar DoS nasty attacks.
 if [ "$SYSCTL" = "" ]
 then
     echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
 else
     $SYSCTL net.ipv4.icmp_echo_ignore_broadcasts="1"
 fi
 
 # This option can be used to accept or refuse source routed
 # packets.  It is usually on by default, but is generally
 # considered a security risk.  This option turns it off.
 if [ "$SYSCTL" = "" ]
 then
     echo "0" > /proc/sys/net/ipv4/conf/all/accept_source_route
     echo "0" > /proc/sys/net/ipv6/conf/all/accept_source_route
 else
     $SYSCTL net.ipv4.conf.all.accept_source_route="0"
     $SYSCTL net.ipv6.conf.all.accept_source_route="0"
 fi
 
 # This option can disable ICMP redirects.  ICMP redirects
 # are generally considered a security risk and shouldn't be
 # needed by most systems using this generator.
 #if [ "$SYSCTL" = "" ]
 #then
 #    echo "0" > /proc/sys/net/ipv4/conf/all/accept_redirects
 #else
 #    $SYSCTL net.ipv4.conf.all.accept_redirects="0"
 #fi
 
 # However, we'll ensure the secure_redirects option is on instead.
 # This option accepts only from gateways in the default gateways list.
 if [ "$SYSCTL" = "" ]
 then
     echo "1" > /proc/sys/net/ipv4/conf/all/secure_redirects
 else
     $SYSCTL net.ipv4.conf.all.secure_redirects="1"
 fi
 
 # This option logs packets from impossible addresses.
 if [ "$SYSCTL" = "" ]
 then
     echo "1" > /proc/sys/net/ipv4/conf/all/log_martians
 else
     $SYSCTL net.ipv4.conf.all.log_martians="1"
 fi
 
 
 ###############################################################################
 #
 # Flush Any Existing Rules or Chains
 #
 
 echo "Flushing Tables ..."
 
 # Reset Default Policies
 $IPT -P INPUT ACCEPT
 $IP6T -P INPUT ACCEPT
 $IPT -P FORWARD ACCEPT
 $IP6T -P FORWARD ACCEPT
 $IPT -P OUTPUT ACCEPT
 $IP6T -P OUTPUT ACCEPT
 $IPT -t nat -P PREROUTING ACCEPT
 $IP6T -t nat -P PREROUTING ACCEPT
 $IPT -t nat -P POSTROUTING ACCEPT
 $IP6T -t nat -P POSTROUTING ACCEPT
 $IPT -t nat -P OUTPUT ACCEPT
 $IP6T -t nat -P OUTPUT ACCEPT
 $IPT -t mangle -P PREROUTING ACCEPT
 $IP6T -t mangle -P PREROUTING ACCEPT
 $IPT -t mangle -P OUTPUT ACCEPT
 $IP6T -t mangle -P OUTPUT ACCEPT
 
 # Flush all rules
 $IPT -F
 $IP6T -F
 $IPT -t nat -F
 $IP6T -t nat -F
 $IPT -t mangle -F
 $IP6T -t mangle -F
 
 # Erase all non-default chains
 $IPT -X
 $IP6T -X
 $IPT -t nat -X
 $IP6T -t nat -X
 $IPT -t mangle -X
 $IP6T -t mangle -X
 
 if [ "$1" = "stop" ]
 then
 	echo "Firewall completely flushed!  Now running with no firewall."
 	exit 0
 fi
 
 ###############################################################################
 #
 # Rules Configuration
 #
 
 ###############################################################################
 #
 # Filter Table
 #
 ###############################################################################
 
 # Set Policies
 
 $IPT -P INPUT DROP
 $IP6T -P INPUT DROP
 $IPT -P OUTPUT DROP
 $IP6T -P OUTPUT DROP
 $IPT -P FORWARD DROP
 $IP6T -P FORWARD DROP
 
 ###############################################################################
 #
 # User-Specified Chains
 #
 # Create user chains to reduce the number of rules each packet
 # must traverse.
 
 echo "Create and populate custom rule chains ..."
 
 # 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
 
 # GRE tunneling for PPTP VPN - inbound
 $IPT -N gre_inbound
 
 # GRE tunneling - outbound
 $IPT -N gre_outbound
 
 # OSPF - inbound
 $IPT -N ospf_inbound
 $IP6T -N ospf_inbound
 
 # OSPF - outbound
 $IPT -N ospf_outbound
 $IP6T -N ospf_outbound
 
 ###############################################################################
 #
 # Populate User Chains
 #
 
 # bad_packets chain
 #
 
 # Drop INVALID packets immediately
 $IPT -A bad_packets -p ALL -m conntrack --ctstate INVALID -j LOG \
     --log-prefix "Invalid packet: "
 $IP6T -A bad_packets -p ALL -m conntrack --ctstate INVALID -j LOG \
     --log-prefix "Invalid packet: "
 
 $IPT -A bad_packets -p ALL -m conntrack --ctstate INVALID -j DROP
 $IP6T -A bad_packets -p ALL -m conntrack --ctstate 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 conntrack --ctstate NEW -j LOG \
     --log-prefix "New not syn: "
 $IP6T -A bad_tcp_packets -p tcp ! --syn -m conntrack --ctstate NEW -j LOG \
     --log-prefix "New not syn: "
 $IPT -A bad_tcp_packets -p tcp ! --syn -m conntrack --ctstate NEW -j DROP
 $IP6T -A bad_tcp_packets -p tcp ! --syn -m conntrack --ctstate NEW -j DROP
 
 $IPT -A bad_tcp_packets -p tcp --tcp-flags ALL NONE -j LOG \
     --log-prefix "Stealth scan: "
 $IP6T -A bad_tcp_packets -p tcp --tcp-flags ALL NONE -j LOG \
     --log-prefix "Stealth scan: "
 $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 LOG \
     --log-prefix "Stealth scan: "
 $IP6T -A bad_tcp_packets -p tcp --tcp-flags ALL ALL -j LOG \
     --log-prefix "Stealth scan: "
 $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 LOG \
     --log-prefix "Stealth scan: "
 $IP6T -A bad_tcp_packets -p tcp --tcp-flags ALL FIN,URG,PSH -j LOG \
     --log-prefix "Stealth scan: "
 $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 LOG \
     --log-prefix "Stealth scan: "
 $IP6T -A bad_tcp_packets -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j LOG \
     --log-prefix "Stealth scan: "
 $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 LOG \
     --log-prefix "Stealth scan: "
 $IP6T -A bad_tcp_packets -p tcp --tcp-flags SYN,RST SYN,RST -j LOG \
     --log-prefix "Stealth scan: "
 $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 LOG \
     --log-prefix "Stealth scan: "
 $IP6T -A bad_tcp_packets -p tcp --tcp-flags SYN,FIN SYN,FIN -j LOG \
     --log-prefix "Stealth scan: "
 $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 LOG \
     --log-prefix "ICMP Fragment: "
 $IPT -A icmp_packets --fragment -p ICMP -j DROP
 
 # Echo - uncomment to allow your system to be pinged.
 # Uncomment the LOG command if you also want to log PING attempts
 #
 # $IPT -A icmp_packets -p ICMP -s 0/0 --icmp-type 8 -j LOG \
 #    --log-prefix "Ping detected: "
 # $IP6T -A icmp_packets -p icmpv6 -s 0/0 --icmpv6-type 128 -j LOG \
 #    --log-prefix "Ping detected: "
  $IPT -A icmp_packets -p ICMP -s 0/0 --icmp-type 8 -j ACCEPT
  $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 128 -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 icmpv6 -s 0/0 --icmpv6-type 128 -j DROP
 
 # Time Exceeded
 $IPT -A icmp_packets -p ICMP -s 0/0 --icmp-type 11 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 3 -j ACCEPT
 
 # additional ICMPv6
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 1 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 2 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 4 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 130 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 131 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 132 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 134 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 135 -j ACCEPT
 $IP6T -A icmp_packets -p icmpv6 -s ::/0 --icmpv6-type 136 -j ACCEPT
 
 # Not matched, so return so it will be logged
 $IPT -A icmp_packets -p ICMP -j RETURN
 $IP6T -A icmp_packets -p icmpv6 -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 --destination-port 137 -j DROP
 $IPT -A udp_inbound -p UDP -s 0/0 --destination-port 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 --destination-port 113 -j REJECT
 $IP6T -A udp_inbound -p UDP -s ::/0 --destination-port 113 -j REJECT
 
 # A more sophisticated configuration could accept the ident requests.
 # $IPT -A udp_inbound -p UDP -s 0/0 --destination-port 113 -j ACCEPT
 # $IP6T -A udp_inbound -p UDP -s 0/0 --destination-port 113 -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 --source-port 67 -s 0/0 --destination-port 68 \
      -j ACCEPT
 $IP6T -A udp_inbound -p UDP --source-port 547 -s fe80::/10 --destination-port 546 -d fe80::/10 \
      -j ACCEPT
 #$IP6T -A udp_inbound -p UDP -s ::/0 --destination-port 547 \
 #     -j ACCEPT
 
 # mDNS
 $IPT -A udp_inbound -p UDP -s 0/0 --destination-port 5353 \
      -j ACCEPT
 $IP6T -A udp_inbound -p UDP -s ::/0 --destination-port 5353 \
      -j ACCEPT
 
 # SNMP
 $IPT -A udp_inbound -p UDP -s 0/0 --destination-port 161 -j ACCEPT
 $IPT -A udp_inbound -p UDP -s 0/0 --destination-port 162 -j ACCEPT
 $IP6T -A udp_inbound -p UDP -s ::/0 --destination-port 161 -j ACCEPT
 $IP6T -A udp_inbound -p UDP -s ::/0 --destination-port 162 -j ACCEPT
 
 # TFTP
 $IPT -A udp_inbound -p UDP -s 0/0 --destination-port 69 -j ACCEPT
 $IP6T -A udp_inbound -p UDP -s ::/0 --destination-port 69 -j ACCEPT
 
 # cups
 $IPT -A udp_inbound -p UDP -s 0/0 --destination-port 631 -j ACCEPT
 $IP6T -A udp_inbound -p UDP -s 0/0 --destination-port 631 -j ACCEPT
 
 # 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 -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 --destination-port 113 -j REJECT
 $IP6T -A tcp_inbound -p TCP -s ::/0 --destination-port 113 -j REJECT
 
 # A more sophisticated configuration could accept the ident requests.
 # $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 113 -j ACCEPT
 # $IP6T -A tcp_inbound -p TCP -s 0/0 --destination-port 113 -j ACCEPT
 
 # sshd rate-limiting
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 22 -m state \
 	        --state NEW -m recent --update --seconds 600 --hitcount 5 -j LOG \
 		    --log-prefix "sshd rate-limit: "
 $IP6T -A tcp_inbound -p TCP -s ::/0 --destination-port 22 -m state \
 	        --state NEW -m recent --update --seconds 600 --hitcount 5 -j LOG \
 		    --log-prefix "sshd rate-limit: "
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 22 -m state \
 	        --state NEW -m recent --update --seconds 600 --hitcount 5 -j DROP
 $IP6T -A tcp_inbound -p TCP -s ::/0 --destination-port 22 -m state \
 	        --state NEW -m recent --update --seconds 600 --hitcount 5 -j DROP
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 22 -m state \
 	        --state NEW -m recent --set
 $IP6T -A tcp_inbound -p TCP -s ::/0 --destination-port 22 -m state \
 	        --state NEW -m recent --set
 
 # sshd
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 22 -j ACCEPT
 $IP6T -A tcp_inbound -p TCP -s ::/0 --destination-port 22 -j ACCEPT
 
 # vnc-zero
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 5900 -j ACCEPT
 $IP6T -A tcp_inbound -p TCP -s ::/0 --destination-port 5900 -j ACCEPT
 
 # vnc-daniel
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 5901 -j ACCEPT
 $IP6T -A tcp_inbound -p TCP -s ::/0 --destination-port 5901 -j ACCEPT
 
 # cups
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 631 -j ACCEPT
 $IP6T -A tcp_inbound -p TCP -s 0/0 --destination-port 631 -j ACCEPT
 
 # httpd
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 80 -j ACCEPT
 $IP6T -A tcp_inbound -p TCP -s 0/0 --destination-port 80 -j ACCEPT
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 443 -j ACCEPT
 $IP6T -A tcp_inbound -p TCP -s 0/0 --destination-port 443 -j ACCEPT
 
 # rsyncd
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 873 -j ACCEPT
 $IP6T -A tcp_inbound -p TCP -s 0/0 --destination-port 873 -j ACCEPT
 
 # pleroma
 $IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 4000 -j ACCEPT
 $IP6T -A tcp_inbound -p TCP -s 0/0 --destination-port 4000 -j ACCEPT
 
 # 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 -j ACCEPT
 
 # gre_inbound
 
 $IPT -A gre_inbound -p gre -s 0/0 -d 0/0 -j ACCEPT
 
 # gre_outbound
 
 $IPT -A gre_outbound -p gre -s 0/0 -d 0/0 -j ACCEPT
 
 # ospf_inbound
 $IPT -A ospf_inbound -p ospf -s 0/0 -d 0/0 -j ACCEPT
 $IP6T -A ospf_inbound -p ospf -s ::/0 -d ::/0 -j ACCEPT
 
 # ospf_outbound
 $IPT -A ospf_outbound -p ospf -s 0/0 -d 0/0 -j ACCEPT
 $IP6T -A ospf_outbound -p ospf -s ::/0 -d ::/0 -j ACCEPT
 
 ###############################################################################
 #
 # INPUT Chain
 #
 
 echo "Process 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
 
 # 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
 $IP6T -A INPUT -p ALL -d ff02::1 -j ACCEPT
 
 
 # Inbound Internet Packet Rules
 
 # Accept Established Connections
 $IPT -A INPUT -p ALL -i $INET_IFACE -m conntrack --ctstate ESTABLISHED,RELATED \
      -j ACCEPT
 $IP6T -A INPUT -p ALL -i $INET_IFACE -m conntrack --ctstate ESTABLISHED,RELATED \
      -j ACCEPT
 
 # Route the rest to the appropriate user chain
 $IPT -A INPUT -p TCP -i $INET_IFACE -j tcp_inbound
 $IP6T -A INPUT -p TCP -i $INET_IFACE -j tcp_inbound
 $IPT -A INPUT -p UDP -i $INET_IFACE -j udp_inbound
 $IP6T -A INPUT -p UDP -i $INET_IFACE -j udp_inbound
 $IPT -A INPUT -p ICMP -i $INET_IFACE -j icmp_packets
 $IP6T -A INPUT -p icmpv6 -i $INET_IFACE -j icmp_packets
 $IPT -A INPUT -p gre -i $INET_IFACE -j gre_inbound
 $IPT -A INPUT -p ospf -i $INET_IFACE -j ospf_inbound
 $IP6T -A INPUT -p ospf -i $INET_IFACE -j ospf_inbound
 
 # 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 died: "
 
 ###############################################################################
 #
 # FORWARD Chain
 #
 
 echo "Process FORWARD chain ..."
 
 # Used if forwarding for a private network
 
 
 ###############################################################################
 #
 # OUTPUT Chain
 #
 
 echo "Process OUTPUT chain ..."
 
 # Generally trust the firewall on output
 
 # However, invalid icmp packets need to be dropped
 # to prevent a possible exploit.
 $IPT -A OUTPUT -p icmp -m conntrack --ctstate INVALID -j DROP
 $IP6T -A OUTPUT -p icmpv6 -m conntrack --ctstate 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
 
 # To internet
 $IPT -A OUTPUT -p ALL -o $INET_IFACE -j ACCEPT
 $IP6T -A OUTPUT -p ALL -o $INET_IFACE -j ACCEPT
 
 # 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 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.
 
 echo "Load rules for nat table ..."
 
 ###############################################################################
 #
 # 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.
 
 echo "Load rules for mangle table ..."