What You'll Learn in This Chapter:
How to manage the Fedora Core 4 firewalling configuration
How to use file permissions in new ways to improve system security
How to protect the root account in several ways
How to automatically log out inactive users
In this chapter, you learn to perform some basic security-oriented optimization on your Linux system. Any Fedora Core 4 can be configured in hundreds of flexible ways to maximize security and safety from outside attacks while still permitting you, the user, to finish the work you need to finish. You should follow along with this chapter and understand the settings discussed here if you plan to use your computer on a network for any period of time.
For server systems, you should also take care to read the notes in Chapters 33, "Offering Network File Services," and 34, "Offering Web and FTP Service," about any network services you plan to provide.
If your system is to be an important network server or will be exposed to a large number of users, you should seriously consider studying Linux security in greater depth than can be presented in a single chapter in a book like this one.
Starting points from the Linux Documentation Project include these two online books:
Fedora Core 4 also includes a system called Security-Enhanced Linux (SELinux), which we don't discuss extensively here, primarily because it can make Linux systems much more difficult to work with. If you're interested in absolute maximum security, however, you should follow the instructions you find in this chapter for enabling SELinux, then visit http://www.nsa.gov/selinux/ for details on configuring and using SELinux.