I've been reading the HOW-TO's on iptables and ip masquerading.

I have a couple of things I don't understand. In the scripts they specify an internal connection and an external connection.
specifically:
EXTIF="eth0"
INTIF="eth1"

My network device is eth0, which is my network card. I connect to the internet and my internal network with this device through my linksys router.
Where does eth1 come from? Is this just a "virtual" device?

Lets say I make the modifications to the sample script. Do I then rename this script rc.firewall?
How do I run this script a) manually or b) automatically when the system boots up?

Thanks

Your Linksys router is acts as your firewall and does you masquerading to the external network (Internet) You don't need to setup iptables if it is not being used as a gateway or firewall.

To run the script, just make sure that
#!/bin/sh
is at the top of the file, and then run it as an executable. To have it run at startup, well I don't know how Mandrake does it, but have one or your rc.* files call it. On slack I have /etc/rc.d/rc.local call rc.firewall.

eth0 and eth1 are names of individual ethernet cards. eth1 is not virtual. It's used if you have 2 network cards in your computer to make it a hub/router/firewall, whatever. Masquerading only applies to you if you have 2 network cards on the computer.

I seem to be making this more complicated than it has to be.
I'm using a linksys router set to gateway. I have port forwarding and all that set on the router.
So from what I'm reading I don't need to be going through all this.

Am I correct in thinking that all I need to do is setup my linux box to listen to port 21?
If so, do I set my host domain or primary domain to the ftp.xxxxxx.com?

So there's only 1 network card on your computer and it goes through an external router. You haveno need for port forwarding in the linux box. That's only needed if the linux machine is the router/firewall itself instead of the external one you have. You shouldn't need to do any routing configuration on your linux box.

Just goes to show you, sometimes the best answer is the simplest.


Thanks for your help