sharing internet connection in linux

parthbakshi · 03-10-2006, 09:09 AM

hi
I want to share my internet connection in linux with windows xp computers ,how am i suppose to do it ,i use suse linux 10.0

tomdkat · 03-10-2006, 10:06 AM

You'll have to make your Linux box a "proxy" of sorts. You can use iptables to provide NAT for the XP boxes. Do a search on this forum for "Internet Connection sharing" and see if you get any useful info. I found a good thread here so I imagine similar threads should exist on this forum.

EDIT: Better yet, if you look in the SuSe forum here, you might find the best answer.

Good luck!

Peace...

foo_bar_foo · 03-10-2006, 11:31 AM

OK lets say you have the windows box connected to eth0
so first allow the connection through your firewall
$IPTABLES -A INPUT -i eth0 -j ACCEPT
then just make a seperate boot script called something like ipmasq and in it or add this to the bottom of you firewll script put
this assumes dialup ppp0 so adjust too your setup

Code:

#!/bin/bash

echo "setting up IPmasquerading......"

IPTABLES='/sbin/iptables'

#All The lines below are NAT routing

# flush any old rules
$IPTABLES -F -t nat

# turn on NAT (IP masquerading for outgoing packets)
$IPTABLES -A POSTROUTING -t nat -o ppp0 -j MASQUERADE

# enable IP forwarding (of incoming packets)
echo 1 > /proc/sys/net/ipv4/ip_forward

and set the address to the Linux box in windows as the default route and there you go

jschiwal · 03-10-2006, 12:26 PM

The ip-tables script given above may not be a good idea. By flushing your tables, you will loose your firewall. You can set the routing table and enable ip_forwarding in YaST. You will want to read the SuSE documentation on how you should enable masquerading in SuSE. This also goes by the name NAT (Network Address Translation). YaST has a section on routing, which you can also reach from the interface setup (Bottom part of the screen). Masquerading is enabled in the SuSE Firewall section of YaST. Of course, read through the relevent sections of the SuSE documentation. You can click on the help (lifesaver) icon, and search for masquerading and routing. When setting up masquerading, also set up the firewall. This is very important.

We have been assuming that the Linux computer is the one connected to the internet. If this is the case, be sure that the inside facing ethernet interface's (nic card) IP address is used as the Default Gateway when setting up XP. Otherwise be sure to set the default gateway address on the linux box to the inside XP address and enable network sharing in XP.

It would be much better to use the Linux computer to interface with the internet. This is because malware is more likely to target XP then linux, and these programs know how to turn of the XP's firewall.

scottmorris · 03-10-2006, 02:52 PM

I have written an article on how to share your Internet connection. It is available from the Novell CoolSolutions website.

foo_bar_foo · 03-10-2006, 06:19 PM

Quote:

Originally Posted by jschiwal

The ip-tables script given above may not be a good idea. By flushing your tables, you will loose your firewall.

nope sorry -- not true

-F flag flushes only the selected chain in the selected table

i put no chain designation so the command flushes all the chains in the nat table.
please note the (-t nat) at the end of the command.

this stuff aint rocket science
read
man iptables

why people need a gui program to do this kind of stuff is a mystery.

tomdkat · 03-10-2006, 07:35 PM

Quote:

Originally Posted by foo_bar_foo

why people need a gui program to do this kind of stuff is a mystery.

I think it's more of a comfort thing.

I'm not opposed to doing this kind of stuff at the command line but if there was a GUI I could use, I would probably use it.

Peace...