#!/bin/sh
#
# rc.firewall - Initial SIMPLE IP Masquerade test for 2.1.x and 2.2.x kernels  
#               using IPCHAINS
#
# Load all required IP MASQ modules
#
#   NOTE:  Only load the IP MASQ modules you need.  All current IP MASQ modules
#          are shown below but are commented out from loading.
 
# Needed to initially load modules
#
/sbin/depmod -a
 
# Supports the proper masquerading of FTP file transfers using the PORT method
#
/sbin/modprobe ip_masq_ftp
 
# Supports the masquerading of RealAudio over UDP.  Without this module,
#       RealAudio WILL function but in TCP mode.  This can cause a reduction
#       in sound quality
#
#/sbin/modprobe ip_masq_raudio
 
# Supports the masquerading of IRC DCC file transfers
#
#/sbin/modprobe ip_masq_irc
 
 
# Supports the masquerading of Quake and QuakeWorld by default.  This modules is
#   for for multiple users behind the Linux MASQ server.  If you are going to  
#   play Quake I, II, and III, use the second example.
#
#   NOTE:  If you get ERRORs loading the QUAKE module, you are running an old
#   -----  kernel that has bugs in it.  Please upgrade to the newest kernel.
#
#Quake I / QuakeWorld (ports 26000 and 27000)
#/sbin/modprobe ip_masq_quake
#
#Quake I/II/III / QuakeWorld (ports 26000, 27000, 27910, 27960)
#/sbin/modprobe ip_masq_quake 26000,27000,27910,27960
 
 
# Supports the masquerading of the CuSeeme video conferencing software
#
#/sbin/modprobe ip_masq_cuseeme
 
#Supports the masquerading of the VDO-live video conferencing software
#
#/sbin/modprobe ip_masq_vdolive
 
 
#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 "1" > /proc/sys/net/ipv4/ip_forward
 
 
#CRITICAL:  Enable automatic IP defragmenting since it is disabled by default  
#           in 2.2.x kernels.  This used to be a compile-time option but the  
#           behavior was changed in 2.2.12
#
echo "1" > /proc/sys/net/ipv4/ip_always_defrag
 
 
# Dynamic IP users:
#
#   If you get your IP address dynamically from SLIP, PPP, or DHCP, enable this #   following option.  This enables dynamic-ip address hacking in IP MASQ,  
#   making the life with Diald and similar programs much easier.
#
echo "1" > /proc/sys/net/ipv4/ip_dynaddr
 
 
# Enable the LooseUDP patch which some Internet-based games require
#
#  If you are trying to get an Internet game to work through your IP MASQ box,
#  and you have set it up to the best of your ability without it working, try
#  enabling this option (delete the "#" character).  This option is disabled
#  by default due to possible internal machine UDP port scanning  
#  vunerabilities.
#
#echo "1" > /proc/sys/net/ipv4/ip_masq_udp_dloose
 
 
# MASQ timeouts
#
#   2 hrs timeout for TCP session timeouts
#  10 sec timeout for traffic after the TCP/IP "FIN" packet is received
#  160 sec timeout for UDP traffic (Important for MASQ'ed ICQ users)  
#
/sbin/ipchains -M -S 7200 10 160
 
 
# DHCP:  For people who receive their external IP address from either DHCP or  
#        BOOTP such as ADSL or Cablemodem users, it is necessary to use the  
#        following before the deny command.  The "bootp_client_net_if_name"  
#        should be replaced the name of the link that the DHCP/BOOTP server  
#        will put an address on to?  This will be something like "eth0",  
#        "eth1", etc.
#
#        This example is currently commented out.
#
#
/sbin/ipchains -A input -j ACCEPT -i eth0 -s 0/0 67 -d 0/0 68 -p udp
 
# Enable simple IP forwarding and Masquerading
#
#  NOTE:  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 interface eth0.
#
#         ** Please change this network number, subnet mask, and your Internet
#         ** connection interface name to match your internal LAN setup
#
/sbin/ipchains -P forward DENY
/sbin/ipchains -A forward -i eth0 -s 192.168.123.0/24 -j MASQ