Land's NAT.sh

[yehlu]

#!/bin/sh
#
# NAT.sh - Initial SIMPLE IP Firewall script for Linux 2.4.x and iptables
#

###########################################################################
#
# 1. Configuration options.
#

#
# 1.1 Internet Configuration.
#

INET_IP="192.168.91.23"
INET_IFACE="eth0"
INET_BROADCAST="192.168.91.255"

#
# 1.1.1 DHCP
#

#
# 1.1.2 PPPoE
#

#
# 1.2 Local Area Network configuration.
#
# your LAN's IP range and localhost IP. /24 means to only use the first 24
# bits of the 32 bit IP address. the same as netmask 255.255.255.0
#

LAN_IP="172.16.0.1"
LAN_IP_RANGE="172.16.0.0/16"
LAN_IFACE="eth1"

#
# 1.3 DMZ Configuration.
#

#
# 1.4 Localhost Configuration.
#

LO_IFACE="lo"
LO_IP="127.0.0.1"

#
# 1.5 IPTables Configuration.
#

IPTABLES="/sbin/iptables"

#
# 1.6 Other Configuration.
#

###########################################################################
#
# 2. Module loading.
#

#
# Needed to initially load modules
#

/sbin/depmod -a

#
# 2.1 Required modules
#

/sbin/modprobe ip_tables
/sbin/modprobe ip_nat_ftp
/sbin/modprobe ip_conntrack
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_conntrack_irc
/sbin/modprobe iptable_filter
/sbin/modprobe iptable_mangle
/sbin/modprobe iptable_nat
/sbin/modprobe ipt_LOG
/sbin/modprobe ipt_limit
/sbin/modprobe ipt_state

#
# 2.2 Non-Required modules
#

#/sbin/modprobe ipt_owner
#/sbin/modprobe ipt_REJECT
#/sbin/modprobe ipt_MASQUERADE
#/sbin/modprobe ip_nat_irc

###########################################################################
#
# 3. /proc set up.
#

#
# 3.1 Required proc configuration
#

echo "1" > /proc/sys/net/ipv4/ip_forward

#
# 3.2 Non-Required proc configuration
#

#echo "1" > /proc/sys/net/ipv4/conf/all/rp_filter
#echo "1" > /proc/sys/net/ipv4/conf/all/proxy_arp
#echo "1" > /proc/sys/net/ipv4/ip_dynaddr

###########################################################################
#
# 4. rules set up.
#

######
# 4.1 Filter table
#

#
# 4.1.1 Set policies
#

$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP

#
# 4.1.2 Create userspecified chains
#

#
# Create chain for bad tcp packets
#

$IPTABLES -N bad_tcp_packets

#
# Create separate chains for ICMP, TCP and UDP to traverse
#

$IPTABLES -N allowed
$IPTABLES -N tcp_packets
$IPTABLES -N udp_packets
$IPTABLES -N icmp_packets

#
# Create separate chains for MAC address checking
#

$IPTABLES -N check_mac

#
# Create separate chains for FDG rules
#

$IPTABLES -N fdg_packets

#
# Create separate chains for OSA rules
#

$IPTABLES -N osa_packets

#
# 4.1.3 Create content in userspecified chains
#

#
# bad_tcp_packets chain
#

$IPTABLES -A bad_tcp_packets -p tcp --tcp-flags SYN,ACK SYN,ACK -m state --state NEW -j REJECT --reject-with tcp-reset
$IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j LOG --log-prefix "New not syn: "
$IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j DROP

#
# allowed chain
#

$IPTABLES -A allowed -p TCP --syn -j ACCEPT
$IPTABLES -A allowed -p TCP -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A allowed -p TCP -j LOG --log-prefix "DROP in allowed chain: "
$IPTABLES -A allowed -p TCP -j DROP

#
# TCP rules
#

#FTP
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 20 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 21 -j allowed
#SSH
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 22 -j allowed
#Telnet
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 23 -j allowed
#SMTP
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 25 -j allowed
#DNS
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 53 -j allowed
#HTTP
#$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 80 -j allowed
#POP3
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 110 -j allowed
#IMAP2
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 143 -j allowed
#IMAP3
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 220 -j allowed
#LDAP
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 389 -j allowed
#HTTPS
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 443 -j allowed
#LDAPS
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 636 -j allowed
#RSYNC
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 873 -j allowed
#FTPS
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 989:990 -j allowed
#TELNETS
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 992 -j allowed
#IMAPS
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 993 -j allowed
#POP3S
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 995 -j allowed
#PPTP
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 1723 -j allowed
#CVS
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 2401 -j allowed
#Yahoo Messenger
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 5050 -j allowed
#ICQ
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 5140 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 5190 -j allowed
#MSN
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 569 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 1863 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 5190 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 6901 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 6891:6900 -j allowed
#EPC
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 3389 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 8000 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 2000 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 1433:1434 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 1444 -j allowed

#
# UDP ports
#

#$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 123 -j ACCEPT
#DNS
$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 53 -j ACCEPT
#Check Secure Client
$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 500 -j ACCEPT
$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 2746 -j ACCEPT
#ICQ
$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 4000 -j ACCEPT
$IPTABLES -A udp_packets -p UDP -s 0/0 --destination-port 2074 -j ACCEPT

#
# In Microsoft Networks you will be swamped by broadcasts. These lines
# will prevent them from showing up in the logs.
#

$IPTABLES -A udp_packets -p UDP -i $INET_IFACE -d $INET_BROADCAST --destination-port 135:139 -j DROP
$IPTABLES -A udp_packets -p UDP -i $INET_IFACE -d 255.255.255.255 --destination-port 135:139 -j DROP

#
# If we get DHCP requests from the Outside of our network, our logs will
# be swamped as well. This rule will block them from getting logged.
#

$IPTABLES -A udp_packets -p UDP -i $INET_IFACE -d 255.255.255.255 --destination-port 67:68 -j DROP

#
# ICMP rules
#

$IPTABLES -A icmp_packets -j LOG --log-prefix "kick in icmp Chain: "
$IPTABLES -A icmp_packets -p ICMP -s 0/0 --icmp-type 8 -j ACCEPT
$IPTABLES -A icmp_packets -p ICMP -s 0/0 --icmp-type 11 -j ACCEPT
$IPTABLES -A icmp_packets -j LOG --log-prefix "End Of ECMP Chain: "

#
# MAC address checking
#
#X24
$IPTABLES -A check_mac -m mac --mac-source 22:BE:12:AC:F4:21 -j fdg_packets
#land-nb X30
$IPTABLES -A check_mac -m mac --mac-source 00:09:6b:d0:bd:1f -j fdg_packets
#$IPTABLES -A check_mac -m mac --mac-source 00:09:6b:d0:bd:1f -j osa_packets
$IPTABLES -A check_mac -j LOG --log-prefix "DROP in check_mac Chain: "
$IPTABLES -A check_mac -j DROP

#
# FDG special rules
#
$IPTABLES -A fdg_packets -j LOG --log-prefix "Kick in fdg_packets Chain: "
$IPTABLES -A fdg_packets -p tcp -s 0/0 --dport 569 -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "DROP MSN 569: "
$IPTABLES -A fdg_packets -p tcp -s 0/0 --dport 1863 -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "DROP MSN 1863: "
$IPTABLES -A fdg_packets -p udp -s 0/0 --dport 5190 -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "DROP MSN 5190: "
$IPTABLES -A fdg_packets -p tcp -s 0/0 --dport 6901 -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "DROP MSN 6901: "
$IPTABLES -A fdg_packets -p tcp -s 0/0 --dport 6891:6900 -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "DROP MSN 6891:6900: "
$IPTABLES -A fdg_packets -p tcp -s 0/0 --dport 569 -j REJECT
$IPTABLES -A fdg_packets -p udp -s 0/0 --dport 1863 -j REJECT
$IPTABLES -A fdg_packets -p tcp -s 0/0 --dport 1863 -j REJECT
$IPTABLES -A fdg_packets -p udp -s 0/0 --dport 5190 -j REJECT
$IPTABLES -A fdg_packets -p udp -s 0/0 --dport 6901 -j REJECT
$IPTABLES -A fdg_packets -p tcp -s 0/0 --dport 6891:6900 -j REJECT
$IPTABLES -A fdg_packets -j osa_packets

#
# OSA golebol rules
#
$IPTABLES -A osa_packets -j LOG --log-prefix "Kick in osa_packets Chain: "
$IPTABLES -A osa_packets -p TCP -i $LAN_IFACE -j tcp_packets
$IPTABLES -A osa_packets -p UDP -i $LAN_IFACE -j udp_packets
$IPTABLES -A osa_packets -p ICMP -i $LAN_IFACE -j icmp_packets
$IPTABLES -A osa_packets -p TCP -j LOG --log-prefix "DROP in osa chain: "
$IPTABLES -A osa_packets -p ALL -j DROP

#
# 4.1.4 INPUT chain
#

#
# Bad TCP packets we don't want.
#

$IPTABLES -A INPUT -p tcp -j bad_tcp_packets

#
# Rules for special networks not part of the Internet
#

#$IPTABLES -A INPUT -p ALL -i $LAN_IFACE -s $LAN_IP_RANGE -j LOG --log-prefix "log by me: "
#$IPTABLES -A INPUT -p ALL -i $LAN_IFACE -s $LAN_IP_RANGE -j ACCEPT
$IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $LO_IP -j ACCEPT
$IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $LAN_IP -j ACCEPT
$IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $INET_IP -j ACCEPT

#
# Special rule for DHCP requests from LAN, which are not caught properly
# otherwise.
#

$IPTABLES -A INPUT -p UDP -i $LAN_IFACE --dport 67 --sport 68 -j ACCEPT

#
# Rules for incoming packets from the internet.
#

$IPTABLES -A INPUT -p ALL -d $INET_IP -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A INPUT -p TCP -i $INET_IFACE -j tcp_packets
$IPTABLES -A INPUT -p UDP -i $INET_IFACE -j udp_packets
$IPTABLES -A INPUT -p ICMP -i $INET_IFACE -j icmp_packets

#
# If you have a Microsoft Network on the outside of your firewall, you may
# also get flooded by Multicasts. We drop them so we do not get flooded by
# logs
#

$IPTABLES -A INPUT -i $INET_IFACE -d 224.0.0.0/8 -j DROP

#
# Log weird packets that don't match the above.
#

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

#
# 4.1.5 FORWARD chain
#

#
# Bad TCP packets we don't want
#

$IPTABLES -A FORWARD -p tcp -j bad_tcp_packets

#
# Accept the packets we actually want to forward
#
#$IPTABLES -A FORWARD -i $LAN_IFACE -j ACCEPT
$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -i $LAN_IFACE -j check_mac

#
# Log weird packets that don't match the above.
#

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

#
# 4.1.6 OUTPUT chain
#

#
# Bad TCP packets we don't want.
#

$IPTABLES -A OUTPUT -p tcp -j bad_tcp_packets

#
# Special OUTPUT rules to decide which IP's to allow.
#

$IPTABLES -A OUTPUT -p ALL -s $LO_IP -j ACCEPT
$IPTABLES -A OUTPUT -p ALL -s $LAN_IP -j ACCEPT
$IPTABLES -A OUTPUT -p ALL -s $INET_IP -j ACCEPT

#
# Log weird packets that don't match the above.
#

$IPTABLES -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "IPT OUTPUT packet died: "

##############################################################################################################
# 4.2 nat table
#

#
# 4.2.1 Set policies
#

#
# 4.2.2 Create user specified chains
#

#
# 4.2.3 Create content in user specified chains
#

#
# 4.2.4 PREROUTING chain
#

#
# 4.2.5 POSTROUTING chain
#

#
# Enable simple IP Forwarding and Network Address Translation
#

$IPTABLES -t nat -A POSTROUTING -o $INET_IFACE -j SNAT --to-source $INET_IP

#
# 4.2.6 OUTPUT chain
##############################################################################################################

##############################################################################################################
# 4.3 mangle table
#

#
# 4.3.1 Set policies
#

#
# 4.3.2 Create user specified chains
#

#
# 4.3.3 Create content in user specified chains
#

#
# 4.3.4 PREROUTING chain
#

#
# 4.3.5 INPUT chain
#

#
# 4.3.6 FORWARD chain
#

#
# 4.3.7 OUTPUT chain
#

#
# 4.3.8 POSTROUTING chain
##############################################################################################################