ZyXEL Communications Prestige 662HW Series, Руководство пользователя

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Prestige 662HW Series User’s Guide
Firewalls 11-11
request for that packet and allowed in. Conversely, an incoming packet masquerading as a
response to a nonexistent 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
♦ To prevent DoS attacks and prevent hackers cracking your network.
♦ 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.
♦ To selectively block/allow inbound or outbound traffic between inside host/networks and
outside host/networks. Remember that filters can not distinguish traffic originating from an
inside host or an outside host by IP address.
♦ The firewall performs better than filtering if you need to check many rules.
♦ Use the firewall if you need routine e-mail reports about your system or need to be alerted
when attacks occur.
♦ 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.