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Firewall Protection and Content Filtering 4-1
v1.0, August 2006
Chapter 4
Firewall Protection and Content Filtering
This chapter describes how to use the content filtering features of the ProSafe VPN Firewall 200 to
protect your network. These features can be found by selecting Security from the main menu and
selecting Block Sites from the submenu of the browser interface.
About Firewall Protection and Content Filtering
The ProSafe VPN Firewall 200 provides you with Web content filtering options, plus browsing
activity reporting and instant alerts via e-mail. Parents and network administrators can establish
restricted access policies based on time-of-day, Web addresses and Web address keywords. You
can also block Internet access by applications and services, such as chat or games.
A firewall is a special category of router that protects one network (the “trusted” network, such as
your LAN) from another (the untrusted network, such as the Internet), while allowing
communication between the two. You can further segment keyword blocking to certain known
groups (see “Managing Groups and Hosts (LAN Groups)” on page 3-6 to set up LAN Groups).
A firewall incorporates the functions of a NAT (Network Address Translation) router, while
adding features for dealing with a hacker intrusion or attack, and for controlling the types of traffic
that can flow between the two networks. Unlike simple Internet sharing NAT routers, a firewall
uses a process called stateful packet inspection to protect your network from attacks and
intrusions. NAT performs a very limited stateful inspection in that it considers whether the
incoming packet is in response to an outgoing request, but true Stateful Packet Inspection goes far
beyond NAT.
Using Rules to Block or Allow Specific Kinds of Traffic
Firewall rules are used to block or allow specific traffic passing through from one side to the other.
You can configure up to 600 rules on the FVX538. Inbound rules (WAN to LAN) restrict access by
outsiders to private resources, selectively allowing only specific outside users to access specific
resources. Outbound rules (LAN to WAN) determine what outside resources local users can have
access to.