ZyWALL 5 User’s Guide
Chapter 9 Firewalls
161
Any protocol that operates in this way must be supported on a case-by-case basis. You can use
the web configurator’s
Custom Services
feature to do this.
9.6 Guidelines For Enhancing Security With Your Firewall
1
Change the default password via SMT or web configurator.
2
Think about access control before you connect a console port to the network in any way,
including attaching a modem to the port. Be aware that a break on the console port might
give unauthorized individuals total control of the firewall, even with access control
configured.
3
Limit who can telnet into your router.
4
Don't enable any local service (such as SNMP or NTP) that you don't use. Any enabled
service could present a potential security risk. A determined hacker might be able to find
creative ways to misuse the enabled services to access the firewall or the network.
5
For local services that are enabled, protect against misuse. Protect by configuring the
services to communicate only with specific peers, and protect by configuring rules to
block packets for the services at specific interfaces.
6
Protect against IP spoofing by making sure the firewall is active.
7
Keep the firewall in a secured (locked) room.
9.7 Packet Filtering Vs Firewall
Below are some comparisons between the ZyWALL’s filtering and firewall functions.
9.7.1 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.
9.7.1.1 When To Use Filtering
1
To block/allow LAN packets by their MAC addresses.
2
To block/allow special IP packets which are neither TCP nor UDP, nor ICMP packets.
3
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 cannot
distinguish traffic originating from an inside host or an outside host by IP address.
4
To block/allow IP trace route.
Summary of Contents for ZyXEL ZyWALL 5
Page 1: ...ZyWALL 5 Internet Security Appliance User s Guide Version 3 64 3 2005 ...
Page 2: ......
Page 26: ...ZyWALL 5 User s Guide 24 ...
Page 44: ...ZyWALL 5 User s Guide 42 ...
Page 86: ...ZyWALL 5 User s Guide 84 Chapter 3 Wizard Setup ...
Page 96: ...ZyWALL 5 User s Guide 94 Chapter 4 LAN Screens ...
Page 102: ...ZyWALL 5 User s Guide 100 Chapter 5 Bridge Screens ...
Page 130: ...ZyWALL 5 User s Guide 128 Chapter 7 WAN Screens Figure 45 WAN PPPoE Encapsulation ...
Page 138: ...ZyWALL 5 User s Guide 136 Chapter 7 WAN Screens Figure 50 Dial Backup Setup ...
Page 144: ...ZyWALL 5 User s Guide 142 Chapter 7 WAN Screens ...
Page 152: ...ZyWALL 5 User s Guide 150 Chapter 8 DMZ Screens ...
Page 179: ...ZyWALL 5 User s Guide Chapter 10 Firewall Screens 177 Figure 73 My Service Rule Configuration ...
Page 220: ...ZyWALL 5 User s Guide 218 Chapter 13 Introduction to IPSec ...
Page 238: ...ZyWALL 5 User s Guide 236 Chapter 14 VPN Screens Figure 110 VPN Rules IKE Network Policy Edit ...
Page 261: ...ZyWALL 5 User s Guide Chapter 15 Certificates 259 Figure 122 My Certificate Details ...
Page 280: ...ZyWALL 5 User s Guide 278 Chapter 16 Authentication Server Figure 133 Local User Database ...
Page 317: ...ZyWALL 5 User s Guide Chapter 19 Bandwidth Management 315 ...
Page 318: ...ZyWALL 5 User s Guide 316 Chapter 19 Bandwidth Management ...
Page 352: ...ZyWALL 5 User s Guide 350 Chapter 21 Remote Management ...
Page 366: ...ZyWALL 5 User s Guide 364 Chapter 23 Logs Screens Figure 188 Log Settings ...
Page 389: ...ZyWALL 5 User s Guide Chapter 24 Maintenance 387 Figure 210 Restart Screen ...
Page 390: ...ZyWALL 5 User s Guide 388 Chapter 24 Maintenance ...
Page 416: ...ZyWALL 5 User s Guide 414 Chapter 27 WAN and Dial Backup Setup ...
Page 432: ...ZyWALL 5 User s Guide 430 Chapter 30 DMZ Setup ...
Page 492: ...ZyWALL 5 User s Guide 490 Chapter 37 System Information Diagnosis ...
Page 508: ...ZyWALL 5 User s Guide 506 Chapter 38 Firmware and Configuration File Maintenance ...
Page 520: ...ZyWALL 5 User s Guide 518 Chapter 40 Remote Management ...
Page 536: ...ZyWALL 5 User s Guide 534 Chapter 42 Troubleshooting Figure 343 Java Sun ...
Page 564: ...ZyWALL 5 User s Guide 562 Appendix C IP Subnetting ...
Page 570: ...ZyWALL 5 User s Guide 568 Appendix E PPTP ...
Page 571: ...ZyWALL 5 User s Guide 569 ...
Page 572: ...ZyWALL 5 User s Guide 570 ...
Page 590: ...ZyWALL 5 User s Guide 588 Appendix G Triangle Route ...
Page 620: ...ZyWALL 5 User s Guide 618 Appendix J Importing Certificates ...
Page 622: ...ZyWALL 5 User s Guide 620 Appendix K Command Interpreter ...
Page 628: ...ZyWALL 5 User s Guide 626 Appendix L Firewall Commands ...
Page 632: ...ZyWALL 5 User s Guide 630 Appendix M NetBIOS Filter Commands ...
Page 638: ...ZyWALL 5 User s Guide 636 Appendix O Brute Force Password Guessing Protection ...
Page 660: ...ZyWALL 5 User s Guide 658 Appendix Q Log Descriptions ...