--- Reply to a message ---
By: Jools Smyth 
->: a Mail 
:>: [voyager] Re: Genesis setting.

> WinRoute is kinda good also, but commercial.

Redhat does it for free with this script

#!/bin/sh
#
# Configure safe networking practices for Linux 2.4
#
# chkconfig: - 06 90
# description: Setup firewalling and network security
#              This assumes your Internet is on a PPP connection
#              and the local (trusted) LAN is eth0.
#
# To install this on a Red Hat 6.x system, save this script as
# /etc/rc.d/init.d/securenet, then run the commands
#
#   chmod 755 /etc/rc.d/init.d/securenet
#   /sbin/chkconfig --add securenet
#   /sbin/chkconfig --level 2345 securenet on
#
# The "iptables" command is available from http://netfilter.kernelnotes.org/
# An rpm-package is available from Red Hat's contrib-section
#
# Henrik St�rner, [EMAIL PROTECTED]
#

PATH=/bin:/sbin:/usr/bin:/usr/sbin


#########################################
# First setup some of the kernel features
#########################################

# Disable forwarding - this is for a standalone system.
# (For masquerading, see below).
echo "0" >/proc/sys/net/ipv4/ip_forward

# Enable syn-cookies (syn-flooding attacks)
echo "1" >/proc/sys/net/ipv4/tcp_syncookies

# Disable ICMP echo-request to broadcast addresses (Smurf amplifier)
echo "1" >/proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

# Shut off source-routing and enable IP spoof detection
# It seems that this must be done for all network interfaces
for f in /proc/sys/net/ipv4/conf/*; do
   # Drop all source-routed packets
   echo "0" >$f/accept_source_route 

   # Enable source-address verification (anti spoofing).
   # The value 2 means use Ingress filtering as per RFC 1812.
   # Overhead is a little more than the simple routing check
   # (enabled with 1) but it negligible for most home users.
   echo "2" >$f/rp_filter
done


######################
# Setup IP firewalling
######################

# Default policies
iptables -P INPUT DROP
# iptables -P INPUT ACCEPT
iptables -P FORWARD DROP
# iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT
# flush them
iptables -F INPUT
iptables -F FORWARD
iptables -F OUTPUT

# Create a common chain for the INPUT and FORWARD handling
# iptables -N block
# iptables -F block

# Allow traffic on established connections
# iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
# Allow new connections if not from the outside
# iptables -A block -m state --state NEW -i ! eth0 -j ACCEPT

# Allow new connections to our public http service
# For home users there are normally none
#
# How to do this depends on whether the service is running on the
# firewall host itself, or on another system "behind" the firewall
# (on the internal LAN, or a separate network segment - so called DMZ).
#
# The following command is needed in both cases:
# iptables -A block -m state --protocol tcp --state NEW --destination-port http -j 
ACCEPT

# If the service is running on another host (here: 192.168.11.22), you must 
# do "port forwarding" like this (no need for ipmasqadm anymore):
# iptables -t nat -A PREROUTING --protocol tcp --destination-port http -j DNAT --to 
192.168.11.22
# iptables -t nat -A PREROUTING --protocol tcp --destination-port ircd -j DNAT --to 
192.168.1.2

# Block anything else
# iptables -A block -j LOG

# Activate the new chain
# iptables -A INPUT -j block
# iptables -A FORWARD -j block


####################
# Setup Masquerading
####################


# Setup NAT for outgoing connections from the local network

### NB: This is disabled by default. If you want to use     ###
###     masquerading, just remove the "###" comment-markers ###
###     from the lines below.                               ###

iptables -t nat -F POSTROUTING
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

# enable hacks
modprobe ip_conntrack_ftp
modprobe ip_conntrack_irc
modprobe ip_nat_ftp
modprobe ip_nat_irc
# now irc and ftp works :-)

#
# NB: On Red Hat systems, forwarding is controlled in /etc/sysctl.conf !
#     You need to set net.ipv4.ip_forward=1 in this file, or the
#     command below will have no effect.
#
echo "1" >/proc/sys/net/ipv4/ip_forward


-- 

 Benny Pedersen  http://xpoint.ldnet.dk/  icq:36248146


� Have a happy Christmas ! 8)

...Injustice anywhere is a threat to justice everywhere.


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