FireWall - Basic knowledge.
 

Hi all,

I am new to firewall. I would like to setup a firewall in my office. The diagram is as below :

my LAN computers --> firewall (SmoothWall) --> router (BroadBand) --> internet

My firewall is a PC with SmoothWall 2.0 Express installed with Green (LAN) and Red (Internet) interface configured. I would like to know whether this setup is good for my small company. I would like to setup a www transparent proxy enabled and configured the firewall to be the gateway for my LAN. My PCs in my LAN just can't go through internet. Can you guys give some advice.

From my experience, the firewall would have the direct connection to the Internet, not your "router".
If the setup works and you are monitoring your logs, then you should be fine. I'd recommend checking into writing your own iptables based firewal, but many people like smoothwall.

I have a router to connect to internet. If possible, I don't want to replace it with a firewall PC. The firewall just forward the packet to the internet through the router. Is it possible or ...?

I was googling for the name of a book that I recommend, and found that the 1st edition is on the web.
http://www.wilyhacker.com/1e/

thanks. but i need a shorter explanation on how to setup one. What IPtables command should I use? I've used iptables before but now i'm using smoothwall. does it nat'ed packet forwarded from green interface to red interface since i've found no nat configuration.

iptablesrocks.org
netfilter.org