Fork bombing a Linux machine as a non-root user

[M.Rudra]

On Fri, 18 Mar 2005 23:32:32 -0600, Les Mikesell <lesmikesell at gmail.com> wrote:
> They don't need physical access, but at least network access to an
> account (login/password) on the system. If you haven't set up
> accounts for others or given out your password, no one will
> be able to cause this problem.

Only we both have access on the Linux machine. Having heard Linux is
more secure was what prompted me to switch to it, but i guess i just
panicked on reading that article.
but a big thanks, to all of you for clearing my doubts. 


> If you have something important, back it up to removable media
> (CD/DVD/tape/USB hard drive, etc.) and keep it offline.  You are
> more likely to have a hardware disk problem or make an error
> yourself that damages the files than to have a security related
> problem.  Good backups will save your data either way.

At our hospital we have a proper system with Linux servers and
backups, staff use a windows-like software custom built to our
requirements.
Its the home connection that was attacked twice online so I want to
install software to secure my home machine.

This Iptable faq mentions that 2 ethernet cards are required to setup
a fire wall.
http://newbiedoc.sourceforge.net/networking/homegateway.html

Is there an alternative to iptables as i dont have 2 cards and how do
i get my kernel version? if my kernel is below 2.4 version is there
any other firewall option on Fedora.
i tried a command with this result " bash: modprobe: command not found
" ... actually most commands as a user give above result.
thanks for your time.
MR