#!/bin/sh

SYSCTL="/sbin/sysctl -w"

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

# Internet Interface
INET_IFACE="eth0"
INET_ADDRESS="109.121.200.222"

# Local Interface Information
LOCAL_IFACE="eth1"
LOCAL_IP="192.168.0.1"
LOCAL_NET="192.168.0.0/24"
LOCAL_BCAST="192.168.0.255"

#Clients Interface Information
CLIENT_IFACE="eth2"
CLIENT_IP="192.168.142.1"
CLIENT_NET="192.168.142.0/24"
CLIENT_BCAST="192.168.142.255"


# Localhost Interface
LO_IFACE="lo"
LO_IP="127.0.0.1"

if [ "$1" = "save" ]
then
	echo -n "Saving firewall to /etc/sysconfig/iptables ... "
	$IPTS > /etc/sysconfig/iptables
	echo "done"
	exit 0
elif [ "$1" = "restore" ]
then
	echo -n "Restoring firewall from /etc/sysconfig/iptables ... "
	$IPTR < /etc/sysconfig/iptables
	echo "done"
	exit 0
fi

echo "Loading kernel modules ..."

# core netfilter module
/sbin/modprobe ip_tables
/sbin/modprobe ip_conntrack
/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/tcp_syncookies
else
    $SYSCTL net.ipv4.tcp_syncookies="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

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

if [ "$SYSCTL" = "" ]
then
    echo "0" > /proc/sys/net/ipv4/conf/all/accept_source_route
else
    $SYSCTL net.ipv4.conf.all.accept_source_route="0"
fi

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

if [ "$SYSCTL" = "" ]
then
    echo "0" > /proc/sys/net/ipv4/conf/all/log_martians
else
    $SYSCTL net.ipv4.conf.all.log_martians="0"
fi


echo "Flushing Tables ..."
$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

# Flush all rules
$IPT -F
$IPT -t nat -F
$IPT -t mangle -F

# Erase all non-default chains
$IPT -X
$IPT -t nat -X
$IPT -t mangle -X

if [ "$1" = "stop" ]
then
	echo "Firewall completely flushed!  Now running with no firewall."
	exit 0
fi

# Set Policies
$IPT -P INPUT DROP
$IPT -P OUTPUT DROP
$IPT -P FORWARD DROP


echo "set traffic control"
/etc/rc.d/rc.ipclient

echo "Create and populate custom rule chains ..."
$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 -i $INET_IFACE -s $LOCAL_NET -j LOG --log-prefix "Illegal source: "
$IPT -A bad_packets -p ALL -i $INET_IFACE -s $LOCAL_NET -j DROP
$IPT -A bad_packets -p ALL -i $INET_IFACE -s $CLIENT_NET -j LOG --log-prefix "Illegal source: "
$IPT -A bad_packets -p ALL -i $INET_IFACE -s $CLIENT_NET -j DROP

$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

# All good, so return
$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 -i $CLIENT_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
$IPT -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
$IPT -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
$IPT -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
$IPT -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

$IPT -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
$IPT -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

$IPT -A bad_tcp_packets -p tcp -j RETURN

$IPT -A icmp_packets --fragment -p ICMP -j LOG  --log-prefix "ICMP Fragment: "
$IPT -A icmp_packets --fragment -p ICMP -j DROP

$IPT -A icmp_packets -p ICMP -s 0/0 --icmp-type 8 -j DROP

$IPT -A icmp_packets -p ICMP -s 0/0 --icmp-type 11 -j ACCEPT

# Not matched, so return so it will be logged
$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

# Not matched, so return for logging
$IPT -A udp_inbound -p UDP -j RETURN

# No match, so ACCEPT
$IPT -A udp_outbound -p UDP -s 0/0 -j ACCEPT

while read IP; do
#WEBMIN
$IPT -A tcp_inbound -p TCP -s $IP --destination-port 10000 -j ACCEPT
#SNORT
$IPT -A tcp_inbound -p TCP -s $IP --destination-port 3000 -j ACCEPT
#MYSQL
$IPT -A FORWARD -p tcp -i $INET_IFACE -s $IP --destination-port 1020 --destination 192.168.0.3 -j ACCEPT
$IPT -A FORWARD -p tcp -i $INET_IFACE -s $IP --destination-port 22 --destination 192.168.0.3 -j ACCEPT
$IPT -A FORWARD -p tcp -i $INET_IFACE -s $IP --destination-port 2222 --destination 192.168.0.7 -j ACCEPT
done < /etc/rc.d/allowed_ips.conf

# HTTP
$IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 80 -j ACCEPT
# Email Server (SMTP)
$IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 25 -j ACCEPT
# Email Server (POP3)
$IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 110 -j ACCEPT
# Email Server (IMAP4)
$IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 143 -j ACCEPT
#PPTP
$IPT -A tcp_inbound -p TCP -s 0/0 --destination-port 1723 -j ACCEPT

#ECHOLINK
$IPT -A FORWARD -p udp -i $INET_IFACE --destination-port 5198 --destination 192.168.0.200 -j ACCEPT
$IPT -A FORWARD -p udp -i $INET_IFACE --destination-port 5199 --destination 192.168.0.200 -j ACCEPT
$IPT -A FORWARD -p tcp -i $INET_IFACE --destination-port 5200 --destination 192.168.0.200 -j ACCEPT

# Not matched, so return so it will be logged
$IPT -A tcp_inbound -p TCP -j RETURN

# No match, so ACCEPT
$IPT -A tcp_outbound -p TCP -s 0/0 -j ACCEPT

echo "Process INPUT chain ..."

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

# Drop bad packets
$IPT -A INPUT -p ALL -j bad_packets
$IPT -A INPUT -p ALL -d 224.0.0.1 -j DROP

# Rules for the private network (accessing gateway system itself)
$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 ALL -i $CLIENT_IFACE -s $CLIENT_NET -j ACCEPT
$IPT -A INPUT -p ALL -i $CLIENT_IFACE -d $CLIENT_BCAST -j ACCEPT
$IPT -A INPUT -p ALL -i ppp+ -s $LOCAL_NET -j ACCEPT
$IPT -A INPUT -p ALL -i ppp+ -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 UDP -i $CLIENT_IFACE --source-port 68 --destination-port 67 -j ACCEPT
# Accept Established Connections
$IPT -A INPUT -p ALL -i $INET_IFACE -m state --state ESTABLISHED,RELATED  -j ACCEPT

# Route the rest to the appropriate user chain
$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

# Drop without logging broadcasts that get this far.
$IPT -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: "


echo "Process FORWARD chain ..."

# Drop bad packets
$IPT -A FORWARD -p ALL -j bad_packets

# Accept TCP packets we want to forward from internal sources
$IPT -A FORWARD -p tcp -i $LOCAL_IFACE -j tcp_outbound
$IPT -A FORWARD -p tcp -i $CLIENT_IFACE -j tcp_outbound
$IPT -A FORWARD -p tcp -i ppp+ -j tcp_outbound

# Accept UDP packets we want to forward from internal sources
$IPT -A FORWARD -p udp -i $LOCAL_IFACE -j udp_outbound
$IPT -A FORWARD -p udp -i $CLIENT_IFACE -j udp_outbound
$IPT -A FORWARD -p udp -i ppp+ -j udp_outbound

# If not blocked, accept any other packets from the internal interface
$IPT -A FORWARD -p ALL -i $LOCAL_IFACE -j ACCEPT
$IPT -A FORWARD -p ALL -i $CLIENT_IFACE -j ACCEPT
$IPT -A FORWARD -p ALL -i ppp+ -j ACCEPT

# Deal with responses from the internet
$IPT -A FORWARD -i $INET_IFACE -m state --state ESTABLISHED,RELATED -j ACCEPT

# Log packets that still don't match
$IPT -A FORWARD -m limit --limit 3/minute --limit-burst 3 -j LOG --log-prefix "FORWARD packet died: "

echo "Process OUTPUT chain ..."
$IPT -A OUTPUT -m state -p icmp --state INVALID -j DROP

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

# To internal network
$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 -s $CLIENT_IP -j ACCEPT
$IPT -A OUTPUT -p ALL -o $CLIENT_IFACE -j ACCEPT
$IPT -A OUTPUT -p ALL -o ppp+ -j ACCEPT

# To internet
$IPT -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: "

echo "Load rules for nat table ..."
$IPT -t nat -A PREROUTING -i $LOCAL_IFACE -p tcp -s $LOCAL_NET --dport 25 -j DNAT --to-destination $LOCAL_IP:25
$IPT -t nat -A PREROUTING -i $LOCAL_IFACE -p tcp -s $LOCAL_NET --dport 587 -j DNAT --to-destination $LOCAL_IP:587

#NAT ECHOLINK
$IPT -t nat -A PREROUTING -p udp -i $INET_IFACE --destination-port 5198 -j DNAT --to-destination 192.168.0.200
$IPT -t nat -A PREROUTING -p udp -i $INET_IFACE --destination-port 5199 -j DNAT --to-destination 192.168.0.200
$IPT -t nat -A PREROUTING -p tcp -i $INET_IFACE --destination-port 5200 -j DNAT --to-destination 192.168.0.200
$IPT -A FORWARD -i $INET_IFACE -d 192.168.0.200 -p tcp --dport 5200 -j tcp_inbound

#NAT ALLOWED IPS
while read IP; do
$IPT -t nat -A PREROUTING -p tcp -i $INET_IFACE --destination-port 9913 -j DNAT --to-destination 192.168.0.3:1020
$IPT -t nat -A PREROUTING -p tcp -i $INET_IFACE --destination-port 22 -j DNAT --to-destination 192.168.0.3:22
$IPT -t nat -A PREROUTING -p tcp -i $INET_IFACE --destination-port 2222 -j DNAT --to-destination 192.168.0.7:22
done < /etc/rc.d/allowed_ips.conf

$IPT -t nat -A POSTROUTING -o $INET_IFACE -j SNAT --to-source $INET_ADDRESS

echo "Load rules for mangle table ..."