IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Organisation Remarks
____________________________________________________________________ .........................................
S 2.72 Requirements on a firewall
Initiation responsibility: Head of IT Section, IT Security Management
Implementation responsibility: IT Security Management, Administrators
Before purchasing a firewall, the following points should be taken into
consideration:
- It must be possible to conceal the structure of the network requiring
protection (computer number, name and mail addresses) so that no
conclusions can be drawn regarding the internal network structure and the
internal users. This can be achieved by using an application gateway, for
example, and two DNS servers.
- The firewall should be able to protect certain computers against attacks
without these computers having to be in the network requiring protection.
No user-specific filter rules have to be established for these computers.
This can be, for example, information servers connected to a dedicated
interface of a packet filter or the application gateway (multi-homed
gateway) (see also S 2.77 Secure Configuration of Other Components).
- The components must be centrally administered via a trustworthy path (e.g.
via a separate network or an encoded connection) and they must be
understandable (e.g. via a graphic interface on a separate computer).
Administration should be performed on a separate computer, i.e. the
required management platform should be on a separate computer so that no
complex and thus error-prone software, such as X-Windows, has to be on
the firewall.
- A firewall configuration which consists of at least two separate units is
recommended. The units must be arranged one after the other so that both
units must be passed for a connection between the two networks. The units
should work with different operating systems and different formats for the
description of filter rules.
The two units can, for example, be a packet filter and an application
gateway. This ensures that errors made during the administration of a
component can be intercepted by the other correctly configured
component.
____________________________________________________________________ .........................................
IT-Baseline Protection Manual: Oktober 2000