Prestige 662HW Series User’s Guide
155
Chapter 13 Firewalls
• Upgrade your software regularly. Many older versions of software, especially web
browsers, have well known security deficiencies. When you upgrade to the latest
versions, you get the latest patches and fixes.
• If you use “chat rooms” or IRC sessions, be careful with any information you reveal to
strangers.
• If your system starts exhibiting odd behavior, contact your ISP. Some hackers will set off
hacks that cause your system to slowly become unstable or unusable.
• Always shred confidential information, particularly about your computer, before
throwing it away. Some hackers dig through the trash of companies or individuals for
information that might help them in an attack.
13.7 Packet Filtering Vs Firewall
Below are some comparisons between the Prestige’s filtering and firewall functions.
13.7.1 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.
13.7.1.1 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.
13.7.2 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.
Содержание P-662HW-63
Страница 6: ...Prestige 662HW Series User s Guide Customer Support 6...
Страница 7: ...Prestige 662HW Series User s Guide 7 Customer Support...
Страница 43: ...Prestige 662HW Series User s Guide 43 Introduction to DSL...
Страница 53: ...Prestige 662HW Series User s Guide 53 Chapter 1 Getting To Know Your Prestige...
Страница 59: ...Prestige 662HW Series User s Guide 59 Chapter 2 Introducing the Web Configurator...
Страница 77: ...Prestige 662HW Series User s Guide 77 Chapter 5 Password Setup...
Страница 89: ...Prestige 662HW Series User s Guide 89 Chapter 7 DMZ...
Страница 111: ...Prestige 662HW Series User s Guide 111 Chapter 8 Wireless LAN Setup...
Страница 127: ...Prestige 662HW Series User s Guide 127 Chapter 9 WAN Setup...
Страница 139: ...Prestige 662HW Series User s Guide 139 Chapter 10 Network Address Translation NAT Screens...
Страница 157: ...Prestige 662HW Series User s Guide 157 Chapter 13 Firewalls...
Страница 203: ...Prestige 662HW Series User s Guide 203 Chapter 16 Content Access Control...
Страница 211: ...Prestige 662HW Series User s Guide 211 Chapter 17 Anti Virus Packet Scan...
Страница 217: ...Prestige 662HW Series User s Guide 217 Chapter 18 Introduction to IPSec...
Страница 249: ...Prestige 662HW Series User s Guide 249 Chapter 20 Remote Management Configuration...
Страница 263: ...Prestige 662HW Series User s Guide 263 Chapter 21 Universal Plug and Play UPnP...
Страница 269: ...Prestige 662HW Series User s Guide 269 Chapter 22 Logs Screens...
Страница 295: ...Prestige 662HW Series User s Guide 295 Chapter 24 Maintenance...
Страница 301: ...Prestige 662HW Series User s Guide 301 Chapter 25 Introducing the SMT...
Страница 305: ...Prestige 662HW Series User s Guide 305 Chapter 26 Menu 1 General Setup...
Страница 319: ...Prestige 662HW Series User s Guide 319 Chapter 29 Wireless LAN Setup...
Страница 325: ...Prestige 662HW Series User s Guide 325 Chapter 30 Internet Access...
Страница 339: ...Prestige 662HW Series User s Guide 339 Chapter 32 Static Route Setup...
Страница 343: ...Prestige 662HW Series User s Guide 343 Chapter 33 Bridging Setup...
Страница 375: ...Prestige 662HW Series User s Guide 375 Chapter 36 Filter Configuration...
Страница 395: ...Prestige 662HW Series User s Guide 395 Chapter 39 System Information and Diagnosis...
Страница 411: ...Prestige 662HW Series User s Guide 411 Chapter 40 Firmware and Configuration File Maintenance...
Страница 417: ...Prestige 662HW Series User s Guide 417 Chapter 41 System Maintenance...
Страница 421: ...Prestige 662HW Series User s Guide 421 Chapter 42 Remote Management...
Страница 433: ...Prestige 662HW Series User s Guide 433 Chapter 44 Call Scheduling...
Страница 449: ...Prestige 662HW Series User s Guide 449 Chapter 46 SA Monitor...
Страница 453: ...Prestige 662HW Series User s Guide 453 Chapter 47 Internal SPTGEN...
Страница 459: ...Prestige 662HW Series User s Guide 459 Appendix A Pin Assignments Figure 290 Ethernet Cable Pin Assignments...
Страница 479: ...Prestige 662HW Series User s Guide 479 Appendix C IP Subnetting...
Страница 485: ...Prestige 662HW Series User s Guide 485 Appendix E Wireless LAN and IEEE 802 11...
Страница 492: ...Prestige 662HW Series User s Guide Appendix H Triangle Route 492...
Страница 493: ...Prestige 662HW Series User s Guide 493 Appendix H Triangle Route...
Страница 525: ...Prestige 662HW Series User s Guide 525 Appendix K Example Internal SPTGEN Screens...
Страница 527: ...Prestige 662HW Series User s Guide 527 Appendix L Command Interpreter...
Страница 529: ...Prestige 662HW Series User s Guide 529 Appendix M Firewall Commands...
Страница 533: ...Prestige 662HW Series User s Guide 533 Appendix N NetBIOS Filter Commands...
Страница 535: ...Prestige 662HW Series User s Guide 535 Appendix O Brute Force Password Guessing Protection...