User's Manual

Chapter 12 Packet Filter
P-660HW-Tx v3 Series User’s Guide
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• The firewall performs stateful inspection. It takes into account the state of
connections it handles so that, for example, a legitimate incoming packet can be
matched with the outbound request for that packet and allowed in. Conversely,
an incoming packet masquerading as a response to a non-existent outbound
request can be blocked.
• The firewall uses session filtering, i.e., smart rules, that enhance the filtering
process and control the network session rather than control individual packets in
a session.
• The firewall provides e-mail service to notify you of routine reports and when
alerts occur.
When To Use The Firewall
1 To prevent DoS attacks and prevent hackers cracking your network.
2 A range of source and destination IP addresses as well as port numbers can be
specified within one firewall rule making the firewall a better choice when complex
rules are required.
3 To selectively block/allow inbound or outbound traffic between inside host/
networks and outside host/networks. Remember that filters cannot distinguish
traffic originating from an inside host or an outside host by IP address.
4 The firewall performs better than filtering if you need to check many rules.
5 Use the firewall if you need routine e-mail reports about your system or need to
be alerted when attacks occur.
6 The firewall can block specific URL traffic that might occur in the future. The URL
can be saved in an Access Control List (ACL) database.