#!/bin/sh
#
# Example for iptables
# 
#

SYSCTL="/sbin/sysctl -w" 

IPT="/sbin/iptables"
IPTS="/sbin/iptables-save"
IPTR="/sbin/iptables-restore"

INET_IFACE="eth0"

LOCAL_IFACE="eth1"
LOCAL_IP="192.168.1.1"
LOCAL_NET="192.168.1.0/24"
LOCAL_BCAST="192.168.1.255"

LO_IFACE="lo"
LO_IP="127.0.0.1"

if [ "$1" = "save" ]
then
  echo -n "Salvando firewall em /etc/sysconfig/iptables ... "
  $IPTS > /etc/sysconfig/iptables
  echo "done"
  exit 0
elif [ "$1" = "restore" ]
then
  echo -n "Restaurando firewall de /etc/sysconfig/iptables ... "
  $IPTR < /etc/sysconfig/iptables
  echo "done"
  exit 0
fi

# Carrega os " kernel modules "
echo "Aguarde, carregando modulos do kernel !!!!"

/sbin/modprobe ip_tables
/sbin/modprobe ip_conntrack
/sbin/modprobe iptable_filter
/sbin/modprobe iptable_mangle
/sbin/modprobe iptable_nat
/sbin/modprobe ipt_LOG
/sbin/modprobe ipt_limit
/sbin/modprobe ipt_MASQUERADE
/sbin/modprobe ipt_owner
/sbin/modprobe ipt_REJECT
/sbin/modprobe ipt_mark
/sbin/modprobe ipt_tcpmss
/sbin/modprobe multiport
/sbin/modprobe ipt_state
/sbin/modprobe ipt_unclean
/sbin/modprobe ip_nat_ftp
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_conntrack_irc


if [ "$SYSCTL" = "" ]
then
    echo "1" > /proc/sys/net/ipv4/ip_forward
else
    $SYSCTL net.ipv4.ip_forward="1"
fi

if [ "$SYSCTL" = "" ]
then
    echo "1" > /proc/sys/net/ipv4/ip_dynaddr
else
    $SYSCTL net.ipv4.ip_dynaddr="1"
fi

if [ "$SYSCTL" = "" ]
then
    echo "1" > /proc/sys/net/ipv4/conf/all/rp_filter
else
    $SYSCTL net.ipv4.conf.all.rp_filter="1"
fi

echo "Aguarde ..."

$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

$IPT -F
$IPT -t nat -F
$IPT -t mangle -F

$IPT -X
$IPT -t nat -X
$IPT -t mangle -X

if [ "$1" = "stop" ]
then
  echo "Flushed "
  exit 0
fi


$IPT -P INPUT DROP
$IPT -P OUTPUT DROP
$IPT -P FORWARD DROP


$IPT -N bad_packets
$IPT -N bad_tcp_packets
$IPT -N icmp_packets
$IPT -N udp_inbound
$IPT -N udp_outbound
$IPT -N tcp_inbound
$IPT -N tcp_outbound


$IPT -A bad_packets -p ALL -m state --state INVALID -j LOG \
    --log-prefix "Invalid packet:"
$IPT -A bad_packets -p ALL -m state --state INVALID -j DROP

$IPT -A bad_packets -p tcp -j bad_tcp_packets

$IPT -A bad_packets -p ALL -j RETURN

$IPT -A bad_tcp_packets -p tcp -i $LOCAL_IFACE -j RETURN


$IPT -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j LOG \
    --log-prefix "New not syn:"
$IPT -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j DROP

# All good, so return
$IPT -A bad_tcp_packets -p tcp -j RETURN

$IPT -A icmp_packets -p ICMP -j RETURN

$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

$IPT -A udp_inbound -p UDP -s 0/0 --source-port 67 --destination-port 68 \
     -j ACCEPT

$IPT -A udp_inbound -p UDP -j RETURN

$IPT -A udp_outbound -p UDP -s 0/0 -j ACCEPT
$IPT -A tcp_inbound -p TCP -j RETURN

$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 194 -j REJECT
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 6667 -j REJECT

$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 23 -j REJECT

$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 22 -j REJECT

# RETIRAR
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 80 -j REJECT

# RETIRAR SE FOR O CASO
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 443 -j REJECT

$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 21 -j REJECT

$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 20 -j REJECT


$IPT -A tcp_outbound -p TCP -s 0/0 -j ACCEPT


echo "INPUTs"

$IPT -A INPUT -p ALL -i $LO_IFACE -j ACCEPT

$IPT -A INPUT -p ALL -j bad_packets


$IPT -A INPUT -p ALL -i $LOCAL_IFACE -s $LOCAL_NET -j ACCEPT
$IPT -A INPUT -p ALL -i $LOCAL_IFACE -d $LOCAL_BCAST -j ACCEPT
$IPT -A INPUT -p UDP -i $LOCAL_IFACE --source-port 68 --destination-port 67 \
     -j ACCEPT
/
$IPT -A INPUT -p ALL -i $INET_IFACE -m state --state ESTABLISHED,RELATED \
     -j ACCEPT


$IPT -A INPUT -p TCP -i $INET_IFACE -j tcp_inbound
$IPT -A INPUT -p UDP -i $INET_IFACE -j udp_inbound
$IPT -A INPUT -p ICMP -i $INET_IFACE -j icmp_packets

$IPT -A INPUT -p ALL -d 255.255.255.255 -j DROP


$IPT -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \
     --log-prefix "INPUT packet died: "

echo "FORWARDs"

$IPT -A FORWARD -p tcp -i $LOCAL_IFACE -j tcp_outbound
$IPT -A FORWARD -p udp -i $LOCAL_IFACE -j udp_outbound
$IPT -A FORWARD -p ALL -i $LOCAL_IFACE -j ACCEPT
$IPT -A FORWARD -i $INET_IFACE -m state --state ESTABLISHED,RELATED \
     -j ACCEPT

$IPT -A FORWARD -m limit --limit 3/minute --limit-burst 3 -j LOG \
     --log-prefix "FORWARD packet died: "

echo "OUTPUT"

$IPT -A OUTPUT -m state -p icmp --state INVALID -j DROP

$IPT -A OUTPUT -p ALL -s $LO_IP -j ACCEPT
$IPT -A OUTPUT -p ALL -o $LO_IFACE -j ACCEPT

$IPT -A OUTPUT -p ALL -s $LOCAL_IP -j ACCEPT
$IPT -A OUTPUT -p ALL -o $LOCAL_IFACE -j ACCEPT

$IPT -A OUTPUT -p ALL -o $INET_IFACE -j ACCEPT

$IPT -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG \
     --log-prefix "pacote OUTPUT morto: "

$IPT -t nat -A PREROUTING -p tcp --destination-port 80 \
     -j REDIRECT --to-ports 8080

$IPT -t nat -A POSTROUTING -o $INET_IFACE -j MASQUERADE