 | The firewall should be able to
support a ``deny all services except
those specifically permitted'' design
policy, even if that is not the
policy used. |
| The firewall should
support your security policy, not impose one. |
| The firewall should be
flexible; it should be able to accommodate new
services and needs if the
security policy of the organization changes. |
| The firewall should contain
advanced authentication measures or should
contain the hooks for installing
advanced authentication measures. |
| The firewall should employ filtering
techniques to permit or deny
services to specified host systems as
needed. |
| The IP filtering language should be flexible, user-friendly to
program,
and should filter on as many attributes as possible, including
source and
destination IP address, protocol type, source and destination TCP/UDP port,
and inbound and outbound interface. |
| The firewall should
use proxy services for services such as FTP and
TELNET, so that advanced
authentication measures can be employed and
centralized at the firewall. If
services such as NNTP, X, http, or gopher
are required, the firewall should
contain the corresponding proxy services. |
| The firewall should contain the
ability to centralize SMTP access, to
reduce direct SMTP connections between
site and remote systems. This
results in centralized handling of site
e-mail. |
| The firewall should accomodate public access to the site, such
that
public information servers can be protected by the firewall but can
be
segregated from site systems that do not require the public access. |
|
The firewall should contain the ability to concentrate and filter
dial-in
access. |
| The firewall should contain mechanisms for logging traffic
and
suspicious activity, and should contain mechanisms for log reduction
so
that logs are readable and understandable. |
| If the firewall requires
an operating system such as UNIX, a secured
version of the operating system
should be part of the firewall, with other
security tools as necessary to
ensure firewall host integrity. The
operating system should have all patches
installed. |
| The firewall should be developed in a manner that its strength
and
correctness is verifiable. It should be simple in design so that it can
be
understood and maintained. |
| The firewall and any corresponding
operating system should be updated
with patches and other bug fixes in a
timely manner. |
