P-662H/HW-D Series User’s Guide
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Chapter 10 Firewalls
10.7.1 Packet Filtering:
• The router filters packets as they pass through the router’s interface according to the filter
rules you designed.
• Packet filtering is a powerful tool, yet can be complex to configure and maintain,
especially if you need a chain of rules to filter a service.
• Packet filtering only checks the header portion of an IP packet.
10.7.1.1 When To Use Filtering
• To block/allow LAN packets by their MAC addresses.
• To block/allow special IP packets which are neither TCP nor UDP, nor ICMP packets.
• To block/allow both inbound (WAN to LAN) and outbound (LAN to WAN) traffic
between the specific inside host/network "A" and outside host/network "B". If the filter
blocks the traffic from A to B, it also blocks the traffic from B to A. Filters can not
distinguish traffic originating from an inside host or an outside host by IP address.
• To block/allow IP trace route.
10.7.2 Firewall
• The firewall inspects packet contents as well as their source and destination addresses.
Firewalls of this type employ an inspection module, applicable to all protocols, that
understands data in the packet is intended for other layers, from the network layer (IP
headers) up to the application layer.
• 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.
• 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.
10.7.2.1 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.
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Страница 10: ...P 662H HW D Series User s Guide 10 Customer Support ...
Страница 24: ...P 662H HW D Series User s Guide 24 Table of Contents ...
Страница 32: ...P 662H HW D Series User s Guide 32 List of Figures ...
Страница 38: ...P 662H HW D Series User s Guide 38 List of Tables ...
Страница 64: ...P 662H HW D Series User s Guide 64 Chapter 2 Introducing the Web Configurator ...
Страница 84: ...P 662H HW D Series User s Guide 84 Chapter 4 Bandwidth Management Wizard ...
Страница 108: ...P 662H HW D Series User s Guide 108 Chapter 5 WAN Setup ...
Страница 122: ...P 662H HW D Series User s Guide 122 Chapter 6 LAN Setup ...
Страница 155: ...P 662H HW D Series User s Guide Chapter 8 DMZ 155 Figure 81 DMZ Private and Public Address Example ...
Страница 156: ...P 662H HW D Series User s Guide 156 Chapter 8 DMZ ...
Страница 188: ...P 662H HW D Series User s Guide 188 Chapter 11 Firewall Configuration Figure 97 Firewall Edit Rule ...
Страница 202: ...P 662H HW D Series User s Guide 202 Chapter 11 Firewall Configuration ...
Страница 210: ...P 662H HW D Series User s Guide 210 Chapter 12 Anti Virus Packet Scan ...
Страница 214: ...P 662H HW D Series User s Guide 214 Chapter 13 Content Filtering ...
Страница 232: ...P 662H HW D Series User s Guide 232 Chapter 14 Content Access Control ...
Страница 238: ...P 662H HW D Series User s Guide 238 Chapter 15 Introduction to IPSec ...
Страница 273: ...P 662H HW D Series User s Guide Chapter 17 Certificates 273 Figure 144 My Certificate Details ...
Страница 284: ...P 662H HW D Series User s Guide 284 Chapter 17 Certificates Figure 152 Trusted Remote Host Details ...
Страница 292: ...P 662H HW D Series User s Guide 292 Chapter 18 Static Route ...
Страница 303: ...P 662H HW D Series User s Guide Chapter 19 Bandwidth Management 303 Figure 162 Bandwidth Management Monitor ...
Страница 304: ...P 662H HW D Series User s Guide 304 Chapter 19 Bandwidth Management ...
Страница 308: ...P 662H HW D Series User s Guide 308 Chapter 20 Dynamic DNS Setup ...
Страница 332: ...P 662H HW D Series User s Guide 332 Chapter 22 Universal Plug and Play UPnP ...
Страница 338: ...P 662H HW D Series User s Guide 338 Chapter 23 System ...
Страница 344: ...P 662H HW D Series User s Guide 344 Chapter 24 Logs ...
Страница 350: ...P 662H HW D Series User s Guide 350 Chapter 25 Tools ...
Страница 363: ...P 662H HW D Series User s Guide Chapter 27 Troubleshooting 363 Figure 213 Security Setting ActiveX Controls ...
Страница 364: ...P 662H HW D Series User s Guide 364 Chapter 27 Troubleshooting ...
Страница 368: ...P 662H HW D Series User s Guide 368 Product Specifications ...
Страница 372: ...P 662H HW D Series User s Guide 372 Appendix C Wall mounting Instructions ...
Страница 408: ...P 662H HW D Series User s Guide 408 Appendix F Wireless LANs ...
Страница 420: ...P 662H HW D Series User s Guide 420 Appendix H Command Interpreter ...
Страница 436: ...P 662H HW D Series User s Guide 436 Appendix L NetBIOS Filter Commands ...
Страница 462: ...P 662H HW D Series User s Guide 462 Appendix M Internal SPTGEN ...
Страница 484: ...P 662H HW D Series User s Guide 484 Appendix P Triangle Route ...