#!/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
$IPT -A tcp_outbound -p TCP -s 10.0.1.32 --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
$IPT -A tcp_outbound -p TCP -s 0/0 --destination-port 3389 -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 81.215.105.147
$IPTABLES -A POSTROUTING -t nat -s 10.0.1.0/32 -o $EXT2IF -j SNAT --to-source 213.139.196.50
$IPTABLES -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
echo -e "\nrc.firewall-iptables v$FWVER done.\n"