Quick Reference Guide

ProSafe VPN Firewall 200 FVX538 Reference Manual
4-2 Firewall Protection and Content Filtering
v1.0, March 2009
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.
A firewall has two default rules, one for inbound traffic and one for outbound. The default rules of
the FVX538 are:
• Inbound: Block all access from outside except responses to requests from the LAN side.
• Outbound: Allow all access from the LAN side to the outside.
The firewall rules for blocking/allowing traffic on the VPN firewall can be applied to LAN/WAN
traffic, DMZ/WAN traffic and LAN/DMZ traffic.
Services-Based Rules
The rules to block traffic are based on the traffic’s category of service.
• Outbound Rules (service blocking) – Outbound traffic is normally allowed unless the
firewall is configured to disallow it.
• Inbound Rules (port forwarding) – Inbound traffic is normally blocked by the firewall
unless the traffic is in response to a request from the LAN side. The firewall can be configured
to allow this otherwise blocked traffic.
Table 4-1. Supported FIrewall Rule Configurations
Traffic Rule Outbound Rules Inbound Rules
LAN WAN 50 50
DMZ WAN 50 50
LAN DMZ 50 50