ZyXEL p-660h-61 Guida Utente

Prestige 660H Series User’s Guide 

Firewalls 

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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 nonexistent outbound request can be blocked. 

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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. 

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The firewall provides e-mail service to notify you of routine reports and when alerts occur. 

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To prevent DoS attacks and prevent hackers cracking your network. 

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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. 

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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. 

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The firewall performs better than filtering if you need to check many rules. 

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Use the firewall if you need routine e-mail reports about your system or need to be alerted 
when attacks occur. 

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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.