Very Computer

Hi,

Consider me a dumbass and a linux newbie.

I want to setup linux as a router and my situation is like this drawing:

windows xp                     linux box (redhat 7.3)
1 NIC card <---cross cable---> eth1
                                eth0---straight cable--->CABLE MODEM

NOTES :
- eth0 which is connected to cable modem automatically gets ip when
redhat boots up ( i am able to access internet on linux box)
- eth1 doesnt, i used : "ifconfig eth1 up" and it got a local ip
starting with 192.x.x.x

How do I route things here so that I can use internet from windows too?

I want to be able to access internet from both machines. Will some
knowledgeable person show me the ropes. IF you could outline the
steps/commands and what have you it would be excellant. Specific
commands and explanations is what i am looking for. Thanks in advance
for the help.

Mohammad

||  windows xp                     linux box (redhat 7.3)
||  1 NIC card <---cross cable---> eth1
||                                  eth0---straight cable--->CABLE MODEM

||  - eth0 which is connected to cable modem automatically gets ip when
||  redhat boots up ( i am able to access internet on linux box)
||  - eth1 doesnt, i used : "ifconfig eth1 up" and it got a local ip
||  starting with 192.x.x.x
||
||  How do I route things here so that I can use internet from windows too?

You need to:

  * Point the XP box to the linux box as its gateway,
  * Configure masquerading (source NAT) on the linux box, and
  * Turn on routing on your linux box.

Go to the relevant HOWTOs for the details.  The NET HOWTO comes to
mind.

Good luck.                                                Vincent.

Well you need to turn ip forwarding on using the following.

echo "1" >/proc/sys/net/ipv4/ipforward - this command will need to be
entered in a boot script for re-boot permanancy

I would recommend using iptables to protect your internal network
using NAT (needed as you are using rfc1918 internal addresses) and
restricting incoming connections. I have written a newsgroup post on
how to turn off ipchains and enable iptables for Redhat, just search
on my alias - codfather.

Also visit www.netfilter.org for many useful tutorials.

codfather

IPTables:
http://www.linuxguruz.org/iptables/howto/iptables-HOWTO.html

But what you really need is:
http://www.linuxguruz.org/iptables/howto/ipnatctl-HOWTO.html