#!/bin/sh
#
# rc.firewall-iptables FWVER=0.76
#
#               Initial SIMPLE IP Masquerade test for 2.6 / 2.4 kernels
#               using IPTABLES.  
#
#               Once IP Masquerading has been tested, with this simple 
#               ruleset, it is highly recommended to use a stronger 
#               IPTABLES ruleset either given later in this HOWTO or 
#               from another reputable resource.
#
#
#
# Log:
#       0.76 - Added comments on why the default policy is ACCEPT
#       0.75 - Added more kernel modules to the comments section
#       0.74 - the ruleset now uses modprobe vs. insmod
#       0.73 - REJECT is not a legal policy yet; back to DROP
#       0.72 - Changed the default block behavior to REJECT not DROP
#       0.71 - Added clarification that PPPoE users need to use
#              "ppp0" instead of "eth0" for their external interface
#       0.70 - Added commented option for IRC nat module
#            - Added additional use of environment variables 
#            - Added additional formatting
#       0.63 - Added support for the IRC IPTABLES module
#       0.62 - Fixed a typo on the MASQ enable line that used eth0
#              instead of $EXTIF
#       0.61 - Changed the firewall to use variables for the internal
#              and external interfaces.
#       0.60 - 0.50 had a mistake where the ruleset had a rule to DROP
#              all forwarded packets but it didn't have a rule to ACCEPT
#              any packets to be forwarded either
#            - Load the ip_nat_ftp and ip_conntrack_ftp modules by default
#       0.50 - Initial draft
#

echo -e "\n\nLoading simple rc.firewall-iptables version $FWVER..\n"


# The location of the iptables and kernel module programs
#
#   If your Linux distribution came with a copy of iptables, 
#   most likely all the programs will be located in /sbin.  If 
#   you manually compiled iptables, the default location will
#   be in /usr/local/sbin
#
# ** Please use the "whereis iptables" command to figure out 
# ** where your copy is and change the path below to reflect 
# ** your setup
#
IPTABLES=/sbin/iptables
IPT=/sbin/iptables
#IPTABLES=/usr/local/sbin/iptables
DEPMOD=/sbin/depmod
MODPROBE=/sbin/modprobe


#Setting the EXTERNAL and INTERNAL interfaces for the network
#
#  Each IP Masquerade network needs to have at least one
#  external and one internal network.  The external network
#  is where the natting will occur and the internal network
#  should preferably be addressed with a RFC1918 private address
#  scheme.
#
#  For this example, "eth0" is external and "eth1" is internal"
#
#
#  NOTE:  If this doesnt EXACTLY fit your configuration, you must 
#         change the EXTIF or INTIF variables above. For example: 
#
#            If you are a PPPoE or analog modem user:
#
#               EXTIF="ppp0" 
#
#
EXT2IF="eth2"
EXTIF="ppp0"
INTIF="eth1"
echo "   External Interface:  $EXTIF"
echo "   Internal Interface:  $INTIF"


#======================================================================
#== No editing beyond this line is required for initial MASQ testing ==


echo -en "   loading modules: "

# Need to verify that all modules have all required dependencies
#
echo "  - Verifying that all kernel modules are ok"
$DEPMOD -a

# With the new IPTABLES code, the core MASQ functionality is now either
# modular or compiled into the kernel.  This HOWTO shows ALL IPTABLES
# options as MODULES.  If your kernel is compiled correctly, there is
# NO need to load the kernel modules manually.  
#
#  NOTE: The following items are listed ONLY for informational reasons.
#        There is no reason to manual load these modules unless your
#        kernel is either mis-configured or you intentionally disabled
#        the kernel module autoloader.
#

# Upon the commands of starting up IP Masq on the server, the
# following kernel modules will be automatically loaded:
#
# NOTE:  Only load the IP MASQ modules you need.  All current IP MASQ 
#        modules are shown below but are commented out from loading.
# ===============================================================

echo "----------------------------------------------------------------------"

#Load the main body of the IPTABLES module - "iptable"
#  - Loaded automatically when the "iptables" command is invoked
#
#  - Loaded manually to clean up kernel auto-loading timing issues
#
#echo -en "ip_tables, "
#$MODPROBE ip_tables


#Load the IPTABLES filtering module - "iptable_filter" 
#  - Loaded automatically when filter policies are activated


#Load the stateful connection tracking framework - "ip_conntrack"
#
# The conntrack  module in itself does nothing without other specific 
# conntrack modules being loaded afterwards such as the "ip_conntrack_ftp"
# module
#
#  - This module is loaded automatically when MASQ functionality is 
#    enabled 
#
#  - Loaded manually to clean up kernel auto-loading timing issues
#
#echo -en "ip_conntrack, "
#$MODPROBE ip_conntrack


#Load the FTP tracking mechanism for full FTP tracking
#
# Enabled by default -- insert a "#" on the next line to deactivate
#
#echo -en "ip_conntrack_ftp, "
#$MODPROBE ip_conntrack_ftp


#Load the IRC tracking mechanism for full IRC tracking
#
# Enabled by default -- insert a "#" on the next line to deactivate
#
#echo -en "ip_conntrack_irc, "
#$MODPROBE ip_conntrack_irc


#Load the general IPTABLES NAT code - "iptable_nat"
#  - Loaded automatically when MASQ functionality is turned on
# 
#  - Loaded manually to clean up kernel auto-loading timing issues
#
#echo -en "iptable_nat, "
#$MODPROBE iptable_nat


#Loads the FTP NAT functionality into the core IPTABLES code
# Required to support non-PASV FTP.
#
# Enabled by default -- insert a "#" on the next line to deactivate
#
#echo -en "ip_nat_ftp, "
#$MODPROBE ip_nat_ftp


#Loads the IRC NAT functionality into the core IPTABLES code
# Required to support NAT of IRC DCC requests
#
# Disabled by default -- remove the "#" on the next line to activate
#
#echo -e "ip_nat_irc"
#$MODPROBE ip_nat_irc

echo "----------------------------------------------------------------------"

# Just to be complete, here is a partial list of some of the other  
# IPTABLES kernel modules and their function.  Please note that most 
# of these modules (the ipt ones) are automatically loaded by the 
# master kernel module for proper operation and don't need to be 
# manually loaded.
# --------------------------------------------------------------------
#
#    ip_nat_snmp_basic - this module allows for proper NATing of some 
#                        SNMP traffic
#
#    iptable_mangle    - this target allows for packets to be 
#                        manipulated for things like the TCPMSS 
#                        option, etc.
#
# --
#
#    ipt_mark       - this target marks a given packet for future action.
#                     This automatically loads the ipt_MARK module
#
#    ipt_tcpmss     - this target allows to manipulate the TCP MSS
#                     option for braindead remote firewalls.
#                     This automatically loads the ipt_TCPMSS module
#
#    ipt_limit      - this target allows for packets to be limited to
#                     to many hits per sec/min/hr
#
#    ipt_multiport  - this match allows for targets within a range
#                     of port numbers vs. listing each port individually
#
#    ipt_state      - this match allows to catch packets with various
#                     IP and TCP flags set/unset
#
#    ipt_unclean    - this match allows to catch packets that have invalid
#                     IP/TCP flags set
#
#    iptable_filter - this module allows for packets to be DROPped, 
#                     REJECTed, or LOGged.  This module automatically 
#                     loads the following modules:
#
#                     ipt_LOG - this target allows for packets to be 
#                               logged
#
#                     ipt_REJECT - this target DROPs the packet and returns 
#                                  a configurable ICMP packet back to the 
#                                  sender.
# 

echo -e "   Done loading modules.\n"



#CRITICAL:  Enable IP forwarding since it is disabled by default since
#
#           Redhat Users:  you may try changing the options in
#                          /etc/sysconfig/network from:
#
#                       FORWARD_IPV4=false
#                             to
#                       FORWARD_IPV4=true
#
echo "   Enabling forwarding.."
echo "1" > /proc/sys/net/ipv4/ip_forward


# Dynamic IP users:
#
#   If you get your IP address dynamically from SLIP, PPP, or DHCP, 
#   enable this following option.  This enables dynamic-address hacking
#   which makes the life with Diald and similar programs much easier.
#
#echo "   Enabling DynamicAddr.."
#echo "1" > /proc/sys/net/ipv4/ip_dynaddr


# Enable simple IP forwarding and Masquerading
#
#  NOTE:  In IPTABLES speak, IP Masquerading is a form of SourceNAT or SNAT.
#
#  NOTE #2:  The following is an example for an internal LAN address in the
#            192.168.0.x network with a 255.255.255.0 or a "24" bit subnet mask
#            connecting to the Internet on external interface "eth0".  This
#            example will MASQ internal traffic out to the Internet but not
#            allow non-initiated traffic into your internal network.
#
#            
#         ** Please change the above network numbers, subnet mask, and your 
#         *** Internet connection interface name to match your setup
#         


#Clearing any previous configuration
#
#  Unless specified, the defaults for INPUT and OUTPUT is ACCEPT
#    The default for FORWARD is DROP (REJECT is not a valid policy)
#
#   Isn't ACCEPT insecure?  To some degree, YES, but this is our testing
#   phase.  Once we know that IPMASQ is working well, I recommend you run
#   the rc.firewall-*-stronger rulesets which set the defaults to DROP but
#   also include the critical additional rulesets to still let you connect to
#   the IPMASQ server, etc.
#

# Reset policy

$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

# Rulelari Temizle

$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

# Policy leri olustur

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



echo " INPUT ayarlari "
$IPTABLES -A INPUT -p tcp --dport 22 -j ACCEPT
$IPTABLES -A INPUT -d 213.139.196.50 -p tcp -m tcp --dport 21 -j ACCEPT 
$IPTABLES -A INPUT -i eth1 -j ACCEPT
$IPTABLES -A INPUT -i lo -j ACCEPT
$IPTABLES -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

#Yonetim Ip
$IPT -A tcp_outbound -p TCP -s 10.0.1.30 --destination-port 1:65535 -j ACCEPT #HalukSafi
$IPT -A tcp_outbound -p TCP -s 10.0.1.5 --destination-port 1:65535 -j ACCEPT #EESSBS
$IPT -A tcp_outbound -p TCP -s 10.0.1.92 --destination-port 1:65535 -j ACCEPT #EESTEST

#Izin Verilenler

$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 20 -j ACCEPT
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 21 -j ACCEPT
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 25 -j ACCEPT
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 80 -j ACCEPT
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 110 -j ACCEPT
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 443 -j ACCEPT
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 8080 -j ACCEPT
#Port Bloklama
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 1:65535 -j REJECT

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

# Allow all on localhost interface
$IPT -A INPUT -p ALL -i lo -j ACCEPT

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

##  Rules for the private network (accessing gateway system itself)
$IPT -A INPUT -p ALL -i $INTIF -s 10.0.1.0/32 -j ACCEPT

# Accept Established Connections
$IPT -A INPUT -p ALL -i $EXTIF -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPT -A INPUT -p ALL -i $EXT2IF -m state --state ESTABLISHED,RELATED -j ACCEPT

# Route the rest to the appropriate user chain
$IPT -A INPUT -p TCP -i $EXTIF -j tcp_inbound
$IPT -A INPUT -p TCP -i $EXT2IF -j tcp_inbound
$IPT -A INPUT -p UDP -i $EXTIF -j udp_inbound
$IPT -A INPUT -p UDP -i $EXT2IF -j udp_inbound
$IPT -A INPUT -p ICMP -i $EXTIF -j icmp_packets
$IPT -A INPUT -p ICMP -i $EXT2IF -j icmp_packets
$IPT -A INPUT -p UDP -i $EXIF -j udp_inbound
$IPT -A INPUT -p UDP -i $EXT2IF -j udp_inbound
$IPT -A INPUT -p ICMP -i $EXTIF -j icmp_packets
$IPT -A INPUT -p ICMP -i $EXT2IF -j icmp_packets

# broadcast protocols.
$IPT -A INPUT -p ALL -d 255.255.255.255 -j DROP
$IPT -A FORWARD -p icmp -m icmp --icmp-type 8 -s 0/0 -j DROP

echo " SBS e HTTP portu yonlendirmesi yapildi"
$IPTABLES -t nat -A PREROUTING -p tcp -i ppp0 --dport 80 -j DNAT --to 10.0.1.5
$IPTABLES -A FORWARD -p TCP -i ppp0 -o eth1 -d 10.0.1.5 --dport 80 -j ACCEPT
$IPTABLES -t nat -A PREROUTING -p tcp -i eth2 --dport 80 -j DNAT --to 10.0.1.5
$IPTABLES -A FORWARD -p TCP -i eth2 -o eth1 -d 10.0.1.5 --dport 80 -j ACCEPT
$IPTABLES -t nat -A PREROUTING -p tcp -i ppp0 --dport 3389 -j DNAT --to 10.0.1.92
$IPTABLES -A FORWARD -p TCP -i ppp0 -o eth1 -d 10.0.1.92 --dport 3389 -j ACCEPT
$IPTABLES -t nat -A PREROUTING -p tcp -i ppp0 --dport 5555 -j DNAT --to 10.0.1.5
$IPTABLES -A FORWARD -p TCP -i ppp0 -o eth1 -d 10.0.1.5 --dport 5555 -j ACCEPT

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 $INTIF -j tcp_outbound

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

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

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

echo "Process OUTPUT chain ..."

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

# Localhost
$IPT -A OUTPUT -p ALL -s 127.0.0.1 -j ACCEPT
$IPT -A OUTPUT -p ALL -o lo -j ACCEPT

# To internal network
$IPT -A OUTPUT -p ALL -s 10.0.1.3 -j ACCEPT
$IPT -A OUTPUT -p ALL -o $INTIF -j ACCEPT

# To internet
$IPT -A OUTPUT -p ALL -o $EXTIF -j ACCEPT
$IPT -A OUTPUT -p ALL -o $EXT2IF -j ACCEPT


echo "   FWD: Allow all connections OUT and only existing and related ones IN"
$IPTABLES -A FORWARD -i $EXTIF -o $INTIF -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -i $EXT2IF -o $INTIF -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -i $INTIF -o $EXTIF -j ACCEPT
$IPTABLES -A FORWARD -i $INTIF -o $EXT2IF -j ACCEPT
$IPTABLES -A FORWARD -j LOG

$IPTABLES -A OUTPUT -p ALL -s 127.0.0.1 -j ACCEPT
echo "   Enabling SNAT (MASQUERADE) functionality on $EXTIF"


echo " Squid Redirect Yapildi"

$IPTABLES -t nat -A PREROUTING -i eth1 -p tcp --destination-port 80 -j REDIRECT --to-port 8080
$IPTABLES -A POSTROUTING -t nat -s 10.0.1.0/32 -o $EXTIF -j SNAT --to-source 81.213.105.100
$IPTABLES -A POSTROUTING -t nat -s 10.0.1.0/32 -o $EXT2IF -j SNAT --to-source 213.139.191.200
$IPTABLES -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

echo -e "\nrc.firewall-iptables v$FWVER done.\n"