If you are looking for a simple guide on manually setting up a firewall using the powerful netfilter/iptables tool, this guide is a pretty good one -
*www.justlinux.com/nhf/Security/IPtables_Basics.html
There are many others out there on the internet, but this one is just right for starting out.
*www.justlinux.com/nhf/Security/IPtables_Basics.html
There are many others out there on the internet, but this one is just right for starting out.