slack. it didn't help.. pls look at given NAT configuration n suggest me
#!/bin/sh
# IPTABLES PROXY script for the Linux 2.4 kernel.
# This script is a derivitive of the script presented in
# the IP Masquerade HOWTO page at:
#
http://www.tldp.org/HOWTO/IP-Masquer...-examples.html
# It was simplified to coincide with the configuration of
# the sample system presented in the Guides section of
#
www.aboutdebian.com
#
# This script is presented as an example for testing ONLY
# and should not be used on a production proxy server.
#
# PLEASE SET THE USER VARIABLES
# IN SECTIONS A AND B OR C
echo -e "\n\nSETTING UP IPTABLES PROXY..."
# === SECTION A
# ----------- FOR EVERYONE
# SET THE INTERFACE DESIGNATION FOR THE NIC CONNECTED TO YOUR INTERNAL NETWORK
# The default value below is for "eth0". This value
# could also be "eth1" if you have TWO NICs in your system.
# You can use the ifconfig command to list the interfaces
# on your system. The internal interface will likely have
# have an address that is in one of the private IP address
# ranges.
# Note that this is an interface DESIGNATION - not
# the IP address of the interface.
# Enter the internal interface's designation for the
# INTIF variable:
INTIF="eth0"
# SET THE INTERFACE DESIGNATION FOR YOUR "EXTERNAL" (INTERNET) CONNECTION
# The default value below is "ppp0" which is appropriate
# for a MODEM connection.
# If you have two NICs in your system change this value
# to "eth0" or "eth1" (whichever is opposite of the value
# set for INTIF above). This would be the NIC connected
# to your cable or DSL modem (WITHOUT a cable/DSL router).
# Note that this is an interface DESIGNATION - not
# the IP address of the interface.
# Enter the external interface's designation for the
# EXTIF variable:
EXTIF="ppp0"
# ! ! ! ! ! Use ONLY Section B *OR* Section C depending on
# ! ! ! ! the type of Internet connection you have.
# === SECTION B
# ----------- FOR THOSE WITH STATIC PUBLIC IP ADDRESSES
# SET YOUR EXTERNAL IP ADDRESS
# If you specified a NIC (i.e. "eth0" or "eth1" for
# the external interface (EXTIF) variable above,
# AND if that external NIC is configured with a
# static, public IP address (assigned by your ISP),
# UNCOMMENT the following EXTIP line and enter the
# IP address for the EXTIP variable:
#EXTIP="your.static.IP.address"
# === SECTION C
# ---------- DIAL-UP MODEM, AND RESIDENTIAL CABLE-MODEM/DSL (Dynamic IP) USERS
# SET YOUR EXTERNAL INTERFACE FOR DYNAMIC IP ADDRESSING
# If you get your IP address dynamically from SLIP, PPP,
# BOOTP, or DHCP, UNCOMMENT the command below.
# (No values have to be entered.)
# Note that if you are uncommenting these lines then
# the EXTIP line in Section B must be commented out.
EXTIP="`/sbin/ifconfig ppp0 | grep 'inet addr' | awk '{print $2}' | sed -e 's/.*://'`"
# -------- No more variable setting beyond this point --------
echo "Loading required stateful/NAT kernel modules..."
/sbin/depmod -a
/sbin/modprobe ip_tables
/sbin/modprobe ip_conntrack
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_conntrack_irc
/sbin/modprobe iptable_nat
/sbin/modprobe ip_nat_ftp
/sbin/modprobe ip_nat_irc
echo " Enabling IP forwarding..."
echo "1" > /proc/sys/net/ipv4/ip_forward
echo "1" > /proc/sys/net/ipv4/ip_dynaddr
echo " External interface: $EXTIF"
echo " External interface IP address is: $EXTIP"
echo " Loading proxy server rules..."
# Clearing any existing rules and setting default policy
iptables -P INPUT ACCEPT
iptables -F INPUT
iptables -P OUTPUT ACCEPT
iptables -F OUTPUT
iptables -P FORWARD DROP
iptables -F FORWARD
iptables -t nat -F
# 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 $INTIF -o $EXTIF -j ACCEPT
iptables -I FORWARD -m tcp -p tcp --dport 110 -j ACCEPT
iptables -I FORWARD -m tcp -p tcp --dport 25 -j ACCEPT
iptables -I FORWARD -m tcp -p tcp --dport 53 -j ACCEPT
iptables -A FORWARD -j DROP
# Enabling SNAT (MASQUERADE) functionality on $EXTIF
iptables -t nat -A POSTROUTING -o $EXTIF -j MASQUERADE
echo -e " Proxy server rule loading complete\n\n"
NATTING)
