Specifications

1
Introduction
firewalls is to fend off attacks directed at your intranet as well as to regulate and
protect clients on your LAN by imposing an access policy.
The first firewall was a non-routing UNIX host connected to two different
networks: one network interface was connected to the Internet and the other one
to a private LAN. To reach the Internet from within the private network, users
had to log in to the UNIX firewall server before they could access any outside
host. To do so, they would start, for example, an X Window–based browser on
the firewall host then export the window to the display of their workstation.
With the browser hosted on the firewall, users had access to both systems at the
same time. However, you should not consider this kind of setup (called “dual
homed system”) for your own network unless you really trust all the users on
it. To understand why, remember that ninety-nine percent of all break-ins on
computer systems start with an attempt to obtain a user account on the targeted
system.
The scope of your firewall solution depends on the required degree of protection,
which may need to be in line with legal regulations in some cases and which
should be determined through a communication analysis. Information about
conducting a communication analysis yourself or obtaining consulting, training,
or support services is available in Help on page 141.
Another factor affecting the operation of a firewall is the state of its documenta-
tion. There should be a way to determine “who has changed what, when, and
how” to trace back whether changes were made by an authorized party. This
will also be quite helpful when it comes to dealing with things like certifications
and audits.
The SuSE Firewall on CD is a product covering the whole range of these issues in
all its details, from packet filtering to setting up a multiple-level firewall. Because
the package is based on Open Source programs, it is also possible to audit the
source code without too much difficulty.
SuSE Firewall on CD 2
The SuSE Firewall on CD consists of the following two product components:
1. the SuSE Live CD for Firewall
2. the SuSE Admin CD for Firewall
For the sake of simplicity, we mostly refer to these in this manual as “Live CD”
and “Admin CD”. The Live CD contains the firewall package proper, which, in
5SuSE Linux – Firewall on CD2