Linux is an operating system that was initially created as a hobby by a young student, Linus Torvalds, at the University of Helsinki in Finland. Linus had an interest in Minix, a small UNIX system, and decided to develop a system that exceeded the Minix standards. He began his work in 1991 when he released version 0.02 and worked steadily until 1994 when version 1.0 of the Linux Kernel was released. The kernel, at the heart of all Linux systems, is developed and released under the GNU General Public License and its source code is freely available to everyone. It is this kernel that forms the base around which a Linux operating system is developed. There are now literally hundreds of companies and organizations and an equal number of individuals that have released their own versions of operating systems based on the Linux kernel.

• Use a firewall, either hardware, software or both for any and every network connection.
• Use anti-virus software and keep it up-to-date.
• Keep operating system files and application files patched and up-to-date.
• Enable shadow password support.
• Always set a password for your BIOS to disallow booting from floppy or cd-rom by changing the BIOS settings. This will block undesireable people from trying to boot your Linux system with a special boot disk and will protect you from people trying to change BIOS feature like allowing boot from floppy drive or booting the server without password prompt.
• Read the Linux Security Tips page at userlocal.com.

Links:

Visit the Linux security website

Google search for all things Linux

Linux information