Sidebar: Obtaining Linux
Linux has been, and still is, developed on the Internet.
Therefore, the
source is also available on the Internet. Two main ftp
servers offering
the Linux source are:
tsx-11.mit.edu:/pub/linux
sunsite.unc.edu:/pub/Linux
Downloading a Linux distribution and all the supporting
packages can be
tedious. So, I recommend buying one of the available
CD-ROM
distributions. A good CD-ROM distribution will greatly
simplify the task
of getting a complete working Linux system running.
One of the most popular Linux distributions is Slackware.
As of this
writing, the most current release is Slackware 3.0.
This release offers
a complete setup for a standalone or networked Linux
system. I used the
Slackware release as a starting point for constructing
the firewall.
Although the Slackware release simplifies the installation
process, you
still should be prepared to do a lot of tweaking and
twiddling. The
standard distribution does not come close to being a
secure firewall
setup. The slackware distribution is commonly "bundled"
with Linux
books. The Yggdrasil "Plug 'n Play" distribution
is also available at
many larger bookstores.
If you decide to use a CD-ROM distribution, check that
you have a
Linux-supported CD-ROM drive. Although drivers are available
for nearly
every drive you can imagine, the precompiled kernels
supplied with the
distribution will usually support only the most common
CD-ROM drives.
You need to be able to mount the CD-ROM using one of
these precompiled
kernels if you are to conveniently install from the
CD-ROM. If the
precompiled kernels don't support your CD-ROM, don't
panic. You may be
able to copy the necessary software packages to a DOS
partition on the
same machine and install it from there.
Also be warned that there is considerable lag between
CD-ROM mastering
and kernel development. It is unlikely that you will
find the 1.3.68
kernel mentioned here on any of the current CD-ROM distributions.
In
fact, some of the current bundled CD-ROMs are still
using a 1.0.x or
1.1.x kernel. You should check carefully before you
buy. A 1.2.x or
later kernel will be much easier to upgrade to function
as a firewall.
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