Configuring firewalls is not easy if you don’t know what you are doing and most of us don’t have the time of the paitience to spend hours figuring out internet security. But having a badly configured firewall is worse than having no firewall ’cause it gives you a false sense of security.
Thankfully there are tools out there that allow you to configure a decent firewall without needing a degree in rocket science. Chris Lynch has written an article on Newsforge which looks at Three tools to help you configure iptables.
Check it out.