[Siglinux] Linux networking problem

Sun, 24 Feb 2002 22:04:04 -0800

I�m running my slack box as my network connection with my cable modem.  I run two network cards with IP tables to share my connection to my windows machines.  I�m having some trouble with my new switch, and I think it�s a problem with my box but I wanted an outside opinion.  My 10BT hub works fine with my network setup, but when I put in my new 100/10 switch my network will freeze and packets just stop going through.  I�m running Linksys network cards in all my machines and I�m thinking that the problem might lay in the fact that the Linux drivers done by Linksys are just a hacked version of the tulip driver.  I�ve tried running my windows machines in all different network settings including 10BT Half Duplex and it still locks up.  I�ve also noticed that it locks up a lot when I�m doing file transfers through my samba setup, which might also be the problem.  I�m not sure really if it�s a problem with my IP tables setup or my samba setup or what.   Anyone have any ideas on where I should be focusing to fix the problem?  I will include my IP tables script down below so that can be viewed.

 

Thanks,

Kelly Shutt

 

 

 

#!/bin/sh

#

# rc.firewall - v0.50

#

#               Initial SIMPLE IP Masquerade test for 2.4.x kernels

#               using IPTABLES

#

# 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.

#

echo -e "\n\nIPMASQ *TEST* rc.firewall ruleset - v0.50\n"

 

 

# The location of the 'iptables' program

#

#   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=/usr/sbin/iptables

 

 

#======================================================================

#== 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"

/sbin/depmod -a

 

# With the new IPTABLES code, the core MASQ functionality is now either

# modular or compiled into the kernel.  This HOWTO compiles ALL IPTABLES

# options as modules.  If your kernel is compiled correctly, there is

# NO need to manually load the kernel modules.

#              

#  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:

# ===============================================================

 

#Load the main body of the IPTABLES module - "iptable"

#  - Loaded automatically when the "iptables" command is invoked

 

#Load the IPTABLES filtering module - "iptable_filter"

#  - Loaded automatically when filter policies are activated

 

#Load the geneal IPTABLES NAT code - "iptable_nat"

#  - Loaded automatically when MASQ functionality is turned on

 

#Load the SNAT IPTABLES "Masq" code - "ipt_MASQUERADE"

#  - Loaded automatically when MASQ functionality is turned on

 

#Load the stateful connection tracking framework - "ip_conntrack"

#

# This module in itself does nothing without other specific

# conntrack modules being loaded as well

#

#  - Loaded automatically when MASQ functionality is enabled

#    to properly MASQ protocols such as IRC, FTP, etc.

 

 

#Loads the OUTGOING FTP NAT functionality into the core IPTABLES code 

#

# Disabled by default -- remove the "#" on the next line to activate

/sbin/insmod ip_nat_ftp

               

 

#Load the INCOMING FTP tracking mechanism for the connection tracking

#code

#       

# Disabled by default -- remove the "#" on the next line to activate

/sbin/insmod ip_conntrack_ftp

 

 

 

#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 packet forwarding in the kernel"

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 dynamic addressing measures"

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 not not

#            allow non-initiated traffic into your internal network.

#

#  NOTE #3:  You must change "eth0" to say "ppp0" if you are a modem user.

#

#         ** Please change the above network numbers, subnet mask, and your

#         *** Internet connection interface name to match your setup 

#

echo "  - Flushing old IP Tables"

$IPTABLES -F

 

echo "  - Setting the default FORWARD policy to 'ACCEPT'"

$IPTABLES -P FORWARD ACCEPT

 

echo "  - Enabling SNAT (IPMASQ) functionality on eth0"

$IPTABLES -t nat -A POSTROUTING -o eth0 -j MASQUERADE

 

echo -e "\nDone.\n"

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