#!/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 ..."