O'Reilly Network: Beyond FirewallsApr 07, 2001, 17:51 (2 Talkback[s])
(Other stories by Carl Constantine)
"So you've taken the time to set up a firewall (you have set up a firewall haven't you?). Regardless of what firewall software you're using, you have to ask, "Now what?"
"As I explained in my previous article, Securing Your Home Network With the Edge Firewall , a firewall is the first line of defense for a home network -- not the entire defense. Now you have to go through each computer on your network rigorously looking for problems and locking down everything as tight as you can. This is especially true for any server machines you may have running."
"For this article, I'm going to focus a bit on how the underlying operating system plays a role in security. I'll also talk about a couple common problems in most default Linux installs and what to do about them. Finally, I'll talk about connectivity and access control and how it affects all your systems, not just your servers."