Code:
#!/bin/sh
#
# rc.firewall-iptables-stronger
#
FWVER=0.88s
# An example of a stronger IPTABLES firewall with IP Masquerade
# support for 2.4.x kernels.
#
# Log:
#
# 0.88s - Updated the commands for dynamically addresses machines and
# to point to an expanded FAQ section for more information
#
# 0.87s - Removed the unused drop-and-logit chain as it was only later
# being deleted anyway
# 0.86s - Fixed a typo that had a preceeding ; instead of a #
# 0.85s - renamed from rc.firewall-2.4-stronger to rc.firewall-iptables-
# stronger to reflect this script works for all IPTABLES enabled
# platforms including 2.6.x kernels
# - fixed an incorrect /24 netmask for the INTIP variable
# - removed the unneeded SED variable
# 0.84s - Changed the defaults from 192.168.1.0 to 192.168.0.x to align
# with the rest of the IPMASQ howto
# 0.83s - Added additional comments to make PORTFW configs more obvious
# 0.82s - Added a special ICMP filter to work around a Netfilter security
# issue
# - renamed the drop-and-log-it rule to reject-and-log-it
# 0.81s - Added an additional comment in the INPUT section for NOT
# allowing all traffic in, but only select traffic
# 0.80s - Added a DISABLED ip_nat_irc kernel module section, changed the
# default of the ip_conntrack_irc to NOT load by default, and
# added additional kernel module comments
# 0.79s - ruleset now uses modprobe instead of insmod
# 0.78s - REJECT is not a legal policy yet; back to DROP
# 0.77s - Changed the default block behavior to REJECT not DROP
# 0.76s - Added a comment about the OPTIONAL WWW ruleset and a comment
# where to put optional PORTFW commands
# 0.75s - Added clarification that PPPoE users need to use
# "ppp0" instead of "eth0" for their external interface
# 0.74s - Changed the EXTIP command to work on NON-English distros
# 0.73s - Added comments in the output section that DHCPd is optional
# and changed the default settings to disabled
# 0.72s - Changed the filter from the INTNET to the INTIP to be
# stateful; moved the command VARs to the top and made the
# rest of the script to use them
# 0.70s - Added a disabled examples for allowing internal DHCP
# and external WWW access to the server
# 0.63s - Added support for the IRC module
# 0.62s - Initial version based upon the basic 2.4.x rc.firewall
echo -e "\nLoading rc.firewall-iptables-STRONGER - version $FWVER..\n"
# The location of various iptables and other shell programs
#
# If your Linux distribution came with a copy of iptables, most
# likely it is located in /sbin. If you manually compiled
# iptables, the default location is 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
IPTABLES=/sbin/iptables
#
LSMOD=/sbin/lsmod
DEPMOD=/sbin/depmod
MODPROBE=/sbin/modprobe
GREP=/bin/grep
AWK=/bin/awk
IFCONFIG=/sbin/ifconfig
#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"
#
EXTIF="wlan0"
INTIF="eth0"
echo " External Interface: $EXTIF"
echo " Internal Interface: $INTIF"
echo " ---"
# Specify your Static IP address here or let the script take care of it
# for you.
#
# If you prefer to use STATIC addresses in your firewalls, un-# out the
# static example below and # out the dynamic line. If you don't care,
# just leave this section alone.
#
# If you have a DYNAMIC IP address, the ruleset already takes care of
# this for you. Please note that the different single and double quote
# characters and the script MATTER.
#
#
# PPP and DHCP (Cablemodem and DSL ) users:
# -----------------------------------------
# PPP: If you get your TCP/IP address via DHCP, **you will need ** to
# enable the # #ed out command below underneath the PPP section AND
# replace the word "eth0" with the name of your EXTERNAL Internet
# connection (ppp0, ippp0, etc) on the lines for "ppp-ip" and "extip".
#
# DHCP and PPP users: The remote DHCP or PPP server can and will change
# IP addresses on you over time. To deal with this, users should configure
# their DHCP or PPP client to re-run the rc.firewall-* ruleset everytime
# the IP address is changed. Please see the "masq-and-dyn-addr" FAQ entry
# in the IPMASQ howto for full details on how to do this.
#
#
# Determine the external IP automatically:
# ----------------------------------------
#
# The following line will determine your external IP address. This
# line is somewhat complex and confusing but it will also work for
# all NON-English Linux distributions:
#
EXTIP="`$IFCONFIG $EXTIF | $AWK \
/$EXTIF/'{next}//{split($0,a,":");split(a[2],a," ");print a[1];exit}'`"
# For users who wish to use STATIC IP addresses:
#
# # out the EXTIP line above and un-# out the EXTIP line below
#
#EXTIP="your.static.PPP.address"
echo " External IP: $EXTIP"
echo " ---"
#*******************************************************************************
# Assign the internal TCP/IP network and IP address
#Edit this line according to ur configuration
INTNET="192.168.0.0/24" # assign your internel network
INTIP="192.168.0.1/32" # assign your eth0 IP and network
#**********************************************************************
echo " Internal Network: $INTNET"
echo " Internal IP: $INTIP"
echo " ---"
# Setting a few other local variables
#
UNIVERSE="0.0.0.0/0"
#======================================================================
#== No editing beyond this line is required for initial MASQ testing ==
# Need to verify that all modules have all required dependencies
#
echo " - Verifying that all kernel modules are ok"
$DEPMOD -a
echo -en " Loading kernel modules: "
# 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.
# ===============================================================
#Load the main body of the IPTABLES module - "ip_tables"
# - Loaded automatically when the "iptables" command is invoked
#
# - Loaded manually to clean up kernel auto-loading timing issues
#
echo -en "ip_tables, "
#
#Verify the module isn't loaded. If it is, skip it
#
if [ -z "` $LSMOD | $GREP ip_tables | $AWK {'print $1'} `" ]; then
$MODPROBE ip_tables
fi
#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, "
#
#Verify the module isn't loaded. If it is, skip it
#
if [ -z "` $LSMOD | $GREP ip_conntrack | $AWK {'print $1'} `" ]; then
$MODPROBE ip_conntrack
fi
#Load the FTP tracking mechanism for full FTP tracking
#
# Enabled by default -- insert a "#" on the next line to deactivate
#
echo -e "ip_conntrack_ftp, "
#
#Verify the module isn't loaded. If it is, skip it
#
if [ -z "` $LSMOD | $GREP ip_conntrack_ftp | $AWK {'print $1'} `" ]; then
$MODPROBE ip_conntrack_ftp
fi
#Load the IRC tracking mechanism for full IRC tracking
#
# Disabled by default -- insert a "#" on the next few lines to activate
#
# echo -en " ip_conntrack_irc, "
#
#Verify the module isn't loaded. If it is, skip it
#
# if [ -z "` $LSMOD | $GREP ip_conntrack_irc | $AWK {'print $1'} `" ]; then
# $MODPROBE ip_conntrack_irc
# fi
#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, "
#
#Verify the module isn't loaded. If it is, skip it
#
if [ -z "` $LSMOD | $GREP iptable_nat | $AWK {'print $1'} `" ]; then
$MODPROBE iptable_nat
fi
#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 -e "ip_nat_ftp"
#
#Verify the module isn't loaded. If it is, skip it
#
if [ -z "` $LSMOD | $GREP ip_nat_ftp | $AWK {'print $1'} `" ]; then
$MODPROBE ip_nat_ftp
fi
#Loads the IRC NAT functionality (for DCC) into the core IPTABLES code
#
# DISABLED by default -- delete the "#" on the next few lines to activate
#
# echo -e "ip_nat_irc"
#
#Verify the module isn't loaded. If it is, skip it
#
# if [ -z "` $LSMOD | $GREP ip_nat_irc | $AWK {'print $1'} `" ]; then
# $MODPROBE ip_nat_irc
# fi
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.
#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 the 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
echo " ---"
#############################################################################
#
# Enable Stronger 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
#
#Clearing any previous configuration
#
# Unless specified, the defaults for INPUT, OUTPUT, and FORWARD to DROP
#
# You CANNOT change this to REJECT as it isn't a vaild policy setting.
# If you want REJECT, you must explictly REJECT at the end of a giving
# INPUT, OUTPUT, or FORWARD chain
#
echo " Clearing any existing rules and setting default policy to DROP.."
$IPTABLES -P INPUT DROP
$IPTABLES -F INPUT
$IPTABLES -P OUTPUT DROP
$IPTABLES -F OUTPUT
$IPTABLES -P FORWARD DROP
$IPTABLES -F FORWARD
$IPTABLES -F -t nat
#Not needed and it will only load the unneeded kernel module
#
#$IPTABLES -F -t mangle
# Delete all User-specified chains
$IPTABLES -X
# Reset all IPTABLES counters
$IPTABLES -Z
#Configuring specific CHAINS for later use in the ruleset
#
# NOTE: Some users prefer to have their firewall silently
# "DROP" packets while others prefer to use "REJECT"
# to send ICMP error messages back to the remote
# machine. The default is "REJECT" but feel free to
# change this below.
#
# NOTE: Without the --log-level set to "info", every single
# firewall hit will goto ALL vtys. This is a very big
# pain.
#
echo " Creating a DROP chain.."
$IPTABLES -N reject-and-log-it
$IPTABLES -A reject-and-log-it -j LOG --log-level info
$IPTABLES -A reject-and-log-it -j REJECT
echo -e "\n - Loading INPUT rulesets"
#######################################################################
# INPUT: Incoming traffic from various interfaces. All rulesets are
# already flushed and set to a default policy of DROP.
#
# loopback interfaces are valid.
#
$IPTABLES -A INPUT -i lo -s $UNIVERSE -d $UNIVERSE -j ACCEPT
# local interface, local machines, going anywhere is valid
#
$IPTABLES -A INPUT -i $INTIF -s $INTNET -d $UNIVERSE -j ACCEPT
# remote interface, claiming to be local machines, IP spoofing, get lost
#
$IPTABLES -A INPUT -i $EXTIF -s $INTNET -d $UNIVERSE -j reject-and-log-it
# external interface, from any source, for ICMP traffic is valid
#
# If you would like your machine to "ping" from the Internet,
# enable this next line
#
#$IPTABLES -A INPUT -i $EXTIF -p ICMP -s $UNIVERSE -d $EXTIP -j ACCEPT
# remote interface, any source, going to the MASQ servers IP address is valid
#
# ENABLE this line if you want ALL Internet traffic to connect to your
# the various servers running on the MASQ server. This includes
# web servers, ssh servers, dns servers, etc.
#
# I DON'T recommend you enable this rule. Instead, only enable specific
# access to select server ports under the "OPTIONAL INPUT Section".
# An example of enabling HTTP (WWW) has been given below:
#
#
#$IPTABLES -A INPUT -i $EXTIF -s $UNIVERSE -d $EXTIP -j ACCEPT
##
# Allow any related traffic coming back to the MASQ server in.
#
# STATEFULLY TRACKED
$IPTABLES -A INPUT -i $EXTIF -s $UNIVERSE -d $EXTIP -m state --state \
ESTABLISHED,RELATED -j ACCEPT
# ----- Begin OPTIONAL INPUT Section -----
#
# DHCPd - Enable the following lines if you run an INTERNAL DHCPd server
#
#$IPTABLES -A INPUT -i $INTIF -p tcp --sport 68 --dport 67 -j ACCEPT
#$IPTABLES -A INPUT -i $INTIF -p udp --sport 68 --dport 67 -j ACCEPT
# HTTPd - Enable the following lines if you run an EXTERNAL WWW server
#
# NOTE: This is NOT needed for simply enabling PORTFW. This is ONLY
# for users that plan on running Apache on the MASQ server itself
#
#echo -e " - Allowing EXTERNAL access to the WWW server"
#$IPTABLES -A INPUT -i $EXTIF -m state --state NEW,ESTABLISHED,RELATED \
# -p tcp -s $UNIVERSE -d $EXTIP --dport 80 -j ACCEPT
######################################################################
#
# ----- End OPTIONAL INPUT Section -----
# Catch all rule, all other incoming is denied and logged.
#
$IPTABLES -A INPUT -s $UNIVERSE -d $UNIVERSE -j reject-and-log-it
# ---------------------------------------------------------------------
echo -e " - Loading OUTPUT rulesets"
#######################################################################
# OUTPUT: Outgoing traffic from various interfaces. All rulesets are
# already flushed and set to a default policy of DROP.
#
# Workaround bug in netfilter
# See http://www.netfilter.org/security/2002-04-02-icmp-dnat.html
#
$IPTABLES -A OUTPUT -m state -p icmp --state INVALID -j DROP
# loopback interface is valid.
#
$IPTABLES -A OUTPUT -o lo -s $UNIVERSE -d $UNIVERSE -j ACCEPT
# local interfaces, any source going to local net is valid
#
$IPTABLES -A OUTPUT -o $INTIF -s $EXTIP -d $INTNET -j ACCEPT
# local interface, MASQ server source going to the local net is valid
#
$IPTABLES -A OUTPUT -o $INTIF -s $INTIP -d $INTNET -j ACCEPT
# outgoing to local net on remote interface, stuffed routing, deny
#
$IPTABLES -A OUTPUT -o $EXTIF -s $UNIVERSE -d $INTNET -j reject-and-log-it
# anything else outgoing on remote interface is valid
#
$IPTABLES -A OUTPUT -o $EXTIF -s $EXTIP -d $UNIVERSE -j ACCEPT
# ----- Begin OPTIONAL OUTPUT Section -----
#
# DHCPd - Enable the following lines if you run an INTERNAL DHCPd server
# - Remove BOTH #s all the #s if you need this functionality.
#
#$IPTABLES -A OUTPUT -o $INTIF -p tcp -s $INTIP --sport 67 \
# -d 255.255.255.255 --dport 68 -j ACCEPT
#$IPTABLES -A OUTPUT -o $INTIF -p udp -s $INTIP --sport 67 \
# -d 255.255.255.255 --dport 68 -j ACCEPT
#
# ----- End OPTIONAL OUTPUT Section -----
# Catch all rule, all other outgoing is denied and logged.
#
$IPTABLES -A OUTPUT -s $UNIVERSE -d $UNIVERSE -j reject-and-log-it
echo -e " - Loading FORWARD rulesets"
#######################################################################
# FORWARD: Enable Forwarding and thus IPMASQ
#
# ----- Begin OPTIONAL FORWARD Section -----
#
# Put PORTFW commands here
#
# ----- End OPTIONAL FORWARD Section -----
echo " - FWD: Allow all connections OUT and only existing/related IN"
$IPTABLES -A FORWARD -i $EXTIF -o $INTIF -m state --state ESTABLISHED,RELATED \
-j ACCEPT
$IPTABLES -A FORWARD -i $INTIF -o $EXTIF -j ACCEPT
# Catch all rule, all other forwarding is denied and logged.
#
$IPTABLES -A FORWARD -j reject-and-log-it
echo " - NAT: Enabling SNAT (MASQUERADE) functionality on $EXTIF"
#
#More liberal form
#$IPTABLES -t nat -A POSTROUTING -o $EXTIF -j MASQUERADE
$IPTABLES -t nat -A POSTROUTING -o eth0 -j MASQUERADE
#
#Stricter form
$IPTABLES -t nat -A POSTROUTING -o $EXTIF -j SNAT --to $EXTIP
#######################################################################
echo -e "\nrc.firewall-iptables-stronger $FWVER done.\n"
#iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j DNAT --to 192.168.0.1:3128
#iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j REDIRECT --to-port 3128
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 3128 -j REDIRECT --to-port 8080
echo -e " Loading Squid rule loading complete\n\n"
let me know what are you doing? If any problem just post your route comand output here.
5 Cups of Ubuntu
).
Originally Posted by superprash2003
Adv Reply
Bookmarks