SIOCSIFADDR: Permission denied

You are running ifconfig eth1 as a regular user. You need to be superuser. The "$" at the end of the prompt indicates a regular user. A "#" indicates superuser.

Either do a sudo command or become "su -" and run the same command from there. I run a Linux firewall (Fedora core 9) and turn on forwarding so that packets will cross between the two cards.

Take a look at the "/sbin/ifup <device>" and the "/sbin/ifdown <device>" where <device>, in your case, is either eth0 or eth1. If the cards are configured, these two commands will toggle the devices on and off. I turn forwarding off/on in my iptables firewall script.

Port forwarding is turned on:

## Enable IP Forwarding
if [ -e /proc/sys/net/ipv4/ip_forward ]; then
echo "1" > /proc/sys/net/ipv4/ip_forward
else
echo "Uh oh: /proc/sys/net/ipv4/ip_forward does not exist"
echo "(That may be a problem)"
echo
fi

"wheel" is a user/group on Sun OS's (and maybe OSX). The Wheel account was/is an account that was slightly less powerful than root. I see what's happening, I think. If you add yourself to the wheel group, then you can run processes of "wheel" privilege. Do a "man pam_wheel".

I broke the kludge the Ubuntu setup for sudo and added a passwd to root. That way I can get a root terminal and use it, instead of one sudo line at a time. Apple and OSX do the same thing. The root password is never divulged. Regular users run root privileges at a lower level than the real "root".

As far as the best OS, I would pick Fedora Core 8. Fedora Core 9 is broken WRT nvidia and X Windows. Though if this firewall machine you are setting up would be "faster" if you didn't run at run level 5 or with a GUI. Bitcommander has programs to check emails and samba connections for viruses. The programs are installed as rpm's or binary shell scripts. That way email are scanned. Also files delivered via Samba are scanned. It doesn't make much point in scanning packets as they are forwarded. It is better to wait until the entire file is downloaded and collected on the disk before a scan is done. I think iptables can scan the contents of a packet for patterns, but with thousands of virus's, I don't think a machine could keep up with a large download. Iptables can block individual sites though by IP address.